Design process

As a starting point we derived a physical model of the flying machine, which helped us to understand the behavior of the system. For instance, as the electric ducted fans are placed farther away from the center of the vehicle, the lever arm of the thrust vectoring system increases – but so does the inertia of the system. These are conflicting requirements for high maneuverability, where one seeks to maximize the lever arm, but still keep the inertia small. The physical model helped us to find a suitable tradeoff.

In parallel, the electric ducted fan and the thrust vectoring mechanism were characterized quantitatively by doing measurements on a separate test bench. In this way, the properties of the actuation – e.g. the total thrust, the time constants of the fan, and the thrust vectoring mechanism – could all be determined experimentally.

Figure 1: The test bench for characterizing the electric ducted fan and the thrust vectoring system.

The measurements on the test bench were used to update the physical model of the flying machine and to assess its flight performance in simulations.

Figure 2: Electric ducted fan with exit nozzle and control flaps.

Key Facts

Flying Platform Website

Researchers
Michael Muehlebach
Raffaello D’Andrea

Mechanical and electrical design
Michael Egli
Marc-Andrè Corzillius

Status
Ongoing research project

Hardware design and specifications

The analysis based on the physical model was used to determine the specifications of the hardware design. The three electric ducted fans (Schübeler DS-51-DIA-HST) were aligned on an equilateral triangle of 30cm side length. A carbon fiber honeycomb structure was used to connect the fans, and a 3D printed exit nozzle was mounted on each fan (see Fig. 2) in order to increase the airflow velocity and augment the thrust vectoring capabilities. The exit nozzle also integrated the two servos that actuate the control flaps. The flaps were optimized for a high stall angle using the XFoil software package (see https://en.wikipedia.org/wiki/XFOIL). Three aluminum feet support the structure when the Flying Platform is on the ground. In total it weighs 7.6kg.

Power is delivered by six 2-cell (or alternatively three 4-cell) battery packs that have a capacity of approximately 6.6Ah. The power consumption at hover is roughly 5.3kW at 120A. A PX4 flight computer is used to run the control algorithms. Each fan delivers a maximum thrust of 4.2kg, which results in a payload of approximately 3kg.

Research on control algorithms

The Flying Platform is used for benchmarking novel control strategies that account for actuation limits. In particular, the flaps are limited to a range of approximately 18°. Control algorithms explicitly accounting for this limitation can provide larger stability margins and other performance enhancements.

We are currently investigating model predictive control algorithms. The idea is to explicitly exploit the physical model of the system – including input and state constraints – for making model-based predictions. Since these methods are computationally expensive, we seek to trade off the prediction accuracy with computational cost, and quantify the consequences of such approximations.

If you liked this article, you may also be interested in:

• Watch flying machines weave a rope bridge you can walk on
• Quadrocopter failsafe algorithm: Recovery after propeller loss
• Quadrocopters learn from prior experience to improve slalom flying

   

• Multiple tethered quadrotors performing high-g, high-speed formation maneuvers 

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Autonomous Systems Lab and Robotics Systems Lab at ETHZ:

This is what happens when a robot wishes for Christmas!

Department of Advanced Robotics (ADVR) at IIT:

Made from the many robots we built at the iCub facility and the ADVR department at ITT.

Want to watch them all? Check out the full playlist on Youtube here:

Researchers are developing an exoskeleton prototype that makes it easier to carry heavy loads. Image courtesy of Robo-Mate.

‘We’re getting sufficient power for sufficiently low weight,’ said Jan Veneman, a roboticist at Tecnalia Research and Innovation in Donostia, Spain.

Exoskeletons typically consist of a framework that covers a person’s limbs. The framework has joints alongside the person’s own skeletal joints, and these are powered by motors or springs to assist in strength or endurance.

Exoskeletons with motors are more flexible and more powerful, whereas those with springs can be made much lighter, according Konrad Stadler, an engineer at the Zurich University of Applied Sciences in Switzerland. Stadler is the technical project manager of the Robo-Mate project, and is working on an exoskeleton that could help manual workers. As part of the EU-funded project, he and his colleagues are designing different exoskeleton ‘modules’ to suit the different tasks carried out by manual workers.

In order to help stimulate innovation in manufacturing, the EU has teamed up with industry and academia in public, private partnerships such as the Partnership for Robotics in Europe and Factories of the Future.

Compression forces

‘Musculoskeletal injuries and disorders are caused by lower back compression forces, which result from the load carried and the worker’s own body weight, as well as the posture of the worker,’ says Stadler.

‘Lifting loads with outstretched arms will produce much larger compression forces in the lower back than lifting the same object close to the body.’

By slipping on a Robo-Mate exoskeleton, a worker trying to carry a heavy object with outstretched arms ought to feel more like he or she is carrying it close to the body. Stadler and colleagues are currently testing a prototype in the lab, and hope to be doing industrial tests next year.

Robo-Mate has made a prototype of an exoskeleton. Image courtesy of Robo-Mate.

But exoskeletons are not all about strength. Veneman is investigating whether exoskeletons can also be used to keep people stable as part of the EU-funded BALANCE project.

The human body normally keeps itself balanced with two mechanisms: altering the stiffness of joints, or moving hands and feet to more stable positions. ‘It is very subtle where you place your foot,’ he explained. ‘If you place it too far, or too close, you can easily lose balance.’

The aim of the BALANCE exoskeleton is to learn how the body does this naturally, and see whether the exoskeleton can assist the body to do the same thing. It is currently in the design stage, but Veneman says the prototype should offer minimal resistance to movement, so that it can follow accurately the movements of healthy and infirm people.

Give a push

Once the system understands the human body’s balancing mechanisms sufficiently well, it should be able to replicate it. In theory, you should be able to give someone wearing the BALANCE prototype a push, and the system will move the person’s feet to stop them falling over.

That will require a rather complex exoskeleton with multiple joints, and sensors that can detect instability.

A simpler exoskeleton, and one with a good chance of commercialisation in the near future, is the one being developed within the EU-funded AXO-SUIT project, which is part of the EU’s Active and Assistive Living programme to enhance quality of life for the elderly. The idea behind AXO-SUIT is to help elderly or infirm people perform basic everyday tasks, such as standing up, walking, reaching and grasping.

The technology behind AXO-SUIT is not dissimilar to that in an electric bike, says project lead coordinator Shaoping Bai of Aalborg University in Denmark. Rather than completely taking over, the motors assist action that the user is already trying to perform, such as bending down to water the plants and standing back up again.

AXO-SUIT is currently at the prototype stage. In about five years, however, Bai hopes that his group will have a commercial version costing between EUR 8 000 and EUR 10 000.

That may sound expensive, but Bai believes the exoskeleton could replace a lot of costly personal care for the elderly. ‘It would be helpful for them to maintain their quality of life while staying at home, rather than move to a care centre,’ he said.

More info

Transcript below.

In this interview, Audrow Nash speaks with Davide Scaramuzza, Assistant Professor of Robotics at the University of Zurich and leader of the Robotics and Perception Group, about autonomous unmanned vehicles (UAV) that navigate using only on-board systems—no GPS or motion capture systems.

Below are some videos of Scaramuzza’s research.

Davide Scaramuzza

Davide Scaramuzza (1980, Italian) is Assistant Professor of Robotics at the University of Zurich. He is founder and director of the Robotics and Perception Group, where he develops cutting-edge research on low-latency vision and visually-guided micro aerial vehicles. He received his PhD (2008) in Robotics and Computer Vision at ETH Zurich (with Roland Siegwart). He was Postdoc at both ETH Zurich and the University of Pennsylvania (with Vijay Kumar and Kostas Daniilidis). From 2009 to 2012, he led the European project “sFly”, which introduced the world’s first autonomous navigation of micro quadrotors in GPS-denied environments using vision as the main sensor modality. For his research contributions, he was awarded an ERC Starting Grant (2014), the IEEE Robotics and Automation Early Career Award (2014), a Google Research Award (2014). He coauthored the book “Introduction to Autonomous Mobile Robots” (MIT Press). He is author of the first open-source Omnidirectional Camera Calibration Toolbox for MATLAB, also used at NASA, Bosch, and Daimler. He is also author of the 1-point RANSAC algorithm, an effective and computationally efficient reduction of the standard 5-point RANSAC for visual odometry, when vehicle motion is non-holonomic. He is Associate Editor of the IEEE Transactions of Robotics and has numerous publications in top-ranked robotics and computer vision journals, such as PAMI, IJCV, T-RO, IJRR, JFR, AURO. His hobbies are piano and magic tricks.

Links:

• Download mp3 (13.3 MB)
• Subscribe to Robots using iTunes
• Subscribe to Robots using RSS
• Robotics and Perception Group website
• Robotics and Perception Group YouTube channel
• Robotics and Perception Group open source software

Transcript

Audrow Nash: Hi, can you introduce yourself.

Davide Scaramuzza: Yeah. My name is Davide Scaramuzza and I am an Assistant Professor at the University of Zurich where I lead the robotics and perception group. My group is about three years old now. Before that I worked at ETH and the University of Pennsylvania. In fact, I got my PhD at ETH Zurich with Professor Roland Siegwart, and then I stayed there for another three years as a post-doc and led a European project called sFLY which was the first project to demonstrate autonomous navigation of vision controlled drones without GPS.

Then I moved to the University of Pennsylvania where I worked with Professors Kostas Daniilidis and Vijay Kumar. Then, in 2012, I got my position as Assistant Professor at the University of Zurich.

Audrow Nash: Now, your research, what is the goal, what are you working towards and what’s your motivation?

Davide Scaramuzza: I’m interested in developing autonomous machines, for both air and ground, that use mainly sensors for navigation and perception. I’m particularly interested in vision because I think vision is the most powerful sense for us humans, and for insects, in general. In fact, most of the brain cortex is dedicated to processing visual images. I’m very interested in exploiting image information for navigation, interpretation, reasoning, path planning and so on.

Audrow Nash: I see. Can you talk a bit about the drone research platform that you’re using with these vision systems?

Davide Scaramuzza: Yes. Since 2009 when I started doing this European project, most of my research has been formed around drones and vision control.

Audrow Nash: Are your drones quadcopters?

Davide Scaramuzza: Yes, we use quadrotors. We assemble them from off the shelf components. Actually, we’re very happy with the air drone but we only use the frame, the motors and the motor controllers from it. We replace the rest of the electronics and put in a PX4 autopilot. We run all our control perception planning algorithms on board on an android and send it to the PX4 autopilot, which we rewrote from scratch.

Audrow Nash: This is done entirely on board the quadrotor?

Davide Scaramuzza: This is all done entirely on board.

Audrow Nash: What are some applications of quadrotor drones, eventually?

Davide Scaramuzza: Well, now you can use quadrotors for search and rescue, law enforcement, room inspection, agriculture, even package delivery. Currently, my group is investing in room inspection for nuclear facilities, like CERN or Fukushima, and reactor buildings. We also have an interest in room inspection for bridges and search and rescue operations, after an earthquake for example. All the applications where GPS is not available, basically, because this allows us to focus on computer vision and visual control tools.

Audrow Nash: Turning to drones that are not using computer vision for navigation exclusively, what other modes of drones are there?

Davide Scaramuzza: If you don’t want to let your drone fly autonomously, the only option you have is a good experienced pilot and usually they use either line-of-site or goggles, so we wirelessly stream video. The problem is that, of course, it’s very difficult to control a drone using line-of-site, especially from far away. Even with goggles it’s difficult. Then, of course, at a certain distance the communication drops so there is nothing you can do.

When this happens you need to have activated the drone to be able to continue the exploration autonomously. Now, how do you localize a drone without GPS? The only way is to rely on the motor sensors; SLAM technology which stands for Simultaneous Localization and Mapping. You build a local map with the environment, then you match it with the global marker available from architectural sketches and the robot uses these algorithms to retrieve a position on the global map. Of course, you can use different sensors for SLAM, such as lasers. They’ve been very successful.

In the last 10 years we’ve seen a boom in visual SLAM using only one camera due to the fact that computer technology has progressed a lot, making it possible to run very sophisticated algorithms on a smaller computer like a Smartphone.

Audrow Nash: What are the problems of using vision on quadrotors?

Davide Scaramuzza: If you compare the performances of vision controlled drones with those remotely controlled, you will notice that vision controlled drones are still limited to controlled environments, which means controlled illumination and texture. Because a vision controlled robot needs texture in order to work, to perceive the environment. If there is no texture it will, basically, crash into the wall. One problem is that we are still restricted to a controlled environment.

Another problem is that vision algorithms are still too slow. We have an average latency, generally speaking, of 50 to 200 milliseconds.

Audrow Nash: Is that because of the sensors or the processing?

Davide Scaramuzza: It’s due to both actually. The processing, on average, takes about 50 to 200 milliseconds a frame, depending on the type of algorithms you’re running. Our semi-direct vision odometry algorithms take only 10 milliseconds on an android, but many vision, SLAM algorithms take much longer, like 30 to 50 milliseconds.

We’re also looking at different types of vision sensors, like event cameras that have an update rate of one million hertz, one mega hertz. They have as many pixels but they do not acquire the image all at the same time but asynchronously, in a similar way as the human eye works. The output is not a frame, it’s a sequence of asynchronous events at micro segment time resolution.

Audrow Nash: That moves into semi-direct visual odometry correct?

Davide Scaramuzza: Well, semi-direct visual odometry still uses high standard sensors.

Audrow Nash: It is similar in the process, is it not?

Davide Scaramuzza: What we’re doing with the event-based sensor is different from semi-direct visual odometry. It’s a different sensor so it’s separate. Before I explain SVO – semi-direct visual odometry – I have to tell you how standard visual odometry algorithms work:

We have two types of visual odometry algorithms. There are visual based or direct methods. Visual based approaches usually extract selling points across images and then they match them.

Audrow Nash: Notable features?

Davide Scaramuzza: Notable features like corners. Primitive features. No lines, small edges, equal edges for example. Then, the next step for visual based algorithms is to match corresponding core-ness across images. Then you apply a motion estimation algorithm, which is basically the core visual odometry. Usually these motion estimation algorithms work by minimizing the projection error between the observed notable points, and they project through the points that are available, from the previous frame for example.

The other approach is to use direct methods, or dense methods, that, instead of extracting several marked points from the images, work with all the pixels. The advantage is that, since you use all the pixels, you will have increased accuracy but you cannot minimize the projection error. Since they’re using photometric error minimization, they only work well if the motion baseline is very small between the two frames; you have to make sure that there is not much distance between consecutive frames.

What we invented is called SVO – semi-direct visual odometry – which, as the name says, leverages the advantages of official base approaches and direct approaches. How do we do that? Well, basically, we use direct methods for a small frame-to-frame motion estimation. Then, instead of future base methods for frame to key frame motion estimation when we’re moving, we skip frames that are too close by. When a certain frame is significantly far from a previous key frame, then we consider the new frame as a key frame and we run an adjustment in respect of the previous key frames.

Audrow Nash: What is a key frame?

Davide Scaramuzza: A key frame is basically a standard frame that is significantly far from the previous frame.

Audrow Nash: Okay. What are some of the projects that you’ve done using semi-direct visual odometry?

Davide Scaramuzza: Research wise, so far, SVO is only working on sparse image points. The next step was to densify the maps and we call these methods “dense methods.” Basically, we use every single pixel in the image; we try to track every single pixel and have a frame of an estimate of it and its uncertainty; a probabilistic filter for each pixel.
We made an app you can download from the iTunes store. It’s called 3D around and uses our remote and SVO technology to allow people to do dense reconstruction – of food, at the moment.

Audrow Nash: Interesting. What are some of the research projects that have come out of this?

Davide Scaramuzza: We are collaborating with industry, so we’re collaborating with sense FLY, which is now part of the parent group. They build drones. Initially, they became popular by making six wing airplanes. They’ve just made a new platform, a quadrotor platform, which is the first quadrotor with five vision sensors. Five cameras are looking in five different directions with small overlaps. The front looking camera has a tilt mechanism that allows it to rotate in any direction. Each of these five vision sensors is coupled with the sonar sensor for distance measurements. Basically, we are importing our technology to this platform.

We’re also collaborating with CERN in Geneva, where the famous particle accelerator is.

Audrow Nash: Going back to sense FLY for just a moment. Using your technology, what kind of things would that allow you to do?

Davide Scaramuzza: The main advantage of using our technology is for inspection operations. It will allow anyone with little or no experience to fly a quadrotor and perform simple inspection operations, like lock to a wall, lock to the surface or get a closer view of an object. The quadrotor will automatically, autonomously approach an object in order to get the best image. There are other things that I am not allowed to say because of confidentiality.

Audrow Nash: You were saying about CERN?

Davide Scaramuzza: We have a project where they want to replicate the conditions of the Big Bang. Every time they do an experiment, they produce a lot of particles and a lot of radioactivity, so you can’t send technicians down there during this time and even for a short while after. Often, they have small accidents and have to very quickly find the cause. We’re working on, one day, replacing the technicians with drones.

Currently, we are interested in automatic inspection of the LHC tunnels, as well as the secondary beam areas of CERN, which is basically the building where all the pipes emerge from the main tunnel and are used to run different experiments.

Audrow Nash: I see. You partner with a lot of companies with this research. Can you talk a bit about pairing with industry? Does your experience working with different companies benefit you and them?

Davide Scaramuzza: I’m very interested in helping companies because we do research to serve the community, which ultimately serves humanity. Many researchers complain that we should focus on research and not bother about the applications, which is the duty of the company. I think that you need applications in order to understand what are the right research questions to ask. Actually, what I like a lot about working in collaboration with companies is that they make you think about robustness; achieving robustness through demonstration.

This robustness basically means that the system works. Ideally, you want it to work 100%, while, in research, you’re happy if it functions at 10%, then you can already prove a concept.

Now robustness actually opens up interesting research questions, it makes you think about what causes the system to fail. What can we do to avoid, for example, the system failing with light? You may want to control the environment using lights on board, or changing the camera parameters.

Companies also benefit because they can have PhD students or post-docs who are working part time on the project.

Audrow Nash: What advice do you have for those beginning their research career?

Davide Scaramuzza: My advice is always to read a lot of papers, work simultaneously, code a lot. I think it’s very important to do both; not just work in theory, but also to understand what you’re working with. Usually, I ask my PhD students to do some hands on experience on drone control and computer vision and, at the same time, start reading papers, a lot of papers. You have to read a lot in order not to reinvent the wheel, reading is very important, and hands on experience.

Audrow Nash: Thank you.

Davide Scaramuzza: Thank you. You’re welcome.

Precisely controlled elastic actuators allow for temporary energy storage – in fact this robotic system consumes 10 times less power than other hydraulic systems. Weighing in at just 26 kg, it can be handled by a single operator, but operates autonomously at a speed of 2km per hour walking or running. Potential applications for such a highly mobile robot include: inspection of industrial, construction, or polluted environments, search and rescue operations, security, or even the entertainment industry.

Further reading:
http://www.leggedrobotics.ethz.ch/doku.php?id=robots:starleth:starleth
http://www.leggedrobotics.ethz.ch/doku.php?id=robots:scarleth
http://www.leggedrobotics.ethz.ch/lib/exe/fetch.php?media=robots:starleth:description:201401_descriptiontransporter.pdf

If you liked this article, you may also be interested in:

• Air and ground robot collaborate to map and safely navigate unknown, changing terrain
•  Robots Podcast #187: Cheetah 2, with Sangbae Kim
• Introducing Spot, a new smaller 4-legged robot from Boston Dynamics
• Firmer footing for robots with smart walking sticks

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Rock Print, Architectural installation at the Chicago Architecture Biennial 2015 from Gramazio Kohler Research, ETH Zurich and the Self-Assembly Lab, MIT

Inspired to take 3D printing technology to new heights, ETH Zurich and MIT researchers create “Rock Print” — a full-scale architectural installation on display at the Chicago Architecture Biennial until January 3, 2016.

Standing over 13 feet (4 metres) high in the Chicago Cultural Center, the monolithic Rock Print installation with its rough and elegant contours confirms that collaboration inspires “State of the Art Architecture” – the theme of the inaugural Chicago Architecture Biennial.

Born out of a 2012 University of Chicago conference that brought architects, engineers, material scientists, and physicists together, Rock Print demonstrates a principle called “jamming” that refers to aggregate granular materials, like gravel that are quite literally crammed together in such a way that they hold their form and shape like a solid, even though their molecular properties are closer (in terms of behaviour) to a liquid substance.

“Jamming” together, researchers from Gramazio Kohler Research, ETH Zurich and Skylar Tibbits’ Self-Assembly Lab at the Massachusetts Institute of Technology (MIT) produced, Rock Print – a zero waste and fully reversible architectural installation for the inauguration of the Chicago Architecture Biennial that opened on 3 October 2015.

Inspired by 3D print technology

“Rock Print is a proof of concept that takes current robotic fabrication technology and applies it to a full-scale architectural project,” said Andreas Thoma, ETH Zurich.

Petrus Aejmelaeus-Lindstroem, lead researcher for the project at ETH Zurich added, “The project shows the capacity of a 3D printing process to create a geometrically-complex construction using two simple components found in everyday life – string and rocks.”

The environmentally conscious ETH and MIT installation team used a custom robotic fabrication setup to lay down nearly 5 miles (9.1 km) of a recycled textile string in a complex pattern guided by a specifically designed algorithm. Like making lasagne, the string is alternated with layers of a loose standard concrete aggregate (rocks) from the Swiss company Misapor. The company makes self-insulating concrete using crushed glass, additives, and a heating process that expands the glass into a foam-like aggregate of mostly air.

While the foam glass is a fraction of the weight of conventional gravel aggregate, Rock Print weighs in at slightly less than one tonne (970 kg to be exact). The weight is a delicate balance – a lighter weight material is necessary for an indoor installation, but the structure of the installation depends on weight to provide strength to the compressional forces that maintain its shape and to compensate for the relatively weak tensional forces.

New possibilities for the future of architecture

Matthias Kohler, who also serves as the Director of the National Competence Centre in Research (NCCR) Digital Fabrication, commented on how 3D printing technology may influence architecture in the future stating, “3D printing technology is an inspiration for the future of architecture as it brings together resource efficient additive building principles with new possibilities for design. Such technology enables production of complex forms and intricate details of building elements at a minimal cost. Today’s commercially available 3D printing technologies are not yet suitable for the scale needed for architecture or its economic and structural demands.”

The Rock Print installation challenges and expands the scope of 3D printing to an architectural scale by introducing robotic fabrication and the use of inexpensive, reconfigurable bulk construction materials. This approach attempts to open new possibilities for future architecture – using advanced digital fabrication technology to build with sustainable and locally available materials.

Kohler says, “There is still a lot of interdisciplinary research needed to fully understand and leverage future digital fabrication principles at a full building scale, but after ten intensive years of research in the field, I am positive that such new principles will not only lead to exciting architecture projects, but also to a new digital building culture – possibly to a socially relevant transformation of our built environment.”

Gramazio Kohler Research, ETH Zurich

The research group headed by Professors Fabio Gramazio and Matthias Kohler at ETH Zurich examines the changes in architectural production that result from the introduction of digital manufacturing techniques. The main focus is ground-breaking research into computational design, constructive systems and their synthesis through the use of novel robotic fabrication technologies. Lindstroem and Thoma indicated that Rock Print was made possible through the collaborative knowledge of architects, engineers, and computational physicists. Prof. Dr. Hans J. Herrmann and Dr. Falk Wittel from ETH Zurich’s Institute for Building Materials and Prof. Dr. Heinrich Jaeger from the University of Chicago consulted on the project.

Gramazio Kohler Research – Rock Print project page

Chicago Architecture Biennial 2015

Rock Print is on display throughout the biennial that runs through 3 January 2016 in the Chicago Cultural Center – the former public library across from the stunning Millennium Park in the heart of the city. Famous for its contemporary architecture and landmark skyscrapers, the Chicago Architecture Biennial celebrates with the theme, “State of the Art in Architecture” providing a platform for ground-breaking architectural projects and spatial experiments that demonstrate how creativity and innovation can radically transform our lived experience. It offers an opportunity to take stock of more than 70 architectural projects and experiments from 30 countries around the world. Rock Print represents the Swiss-US collaboration at the forefront of innovation in architecture.

If you liked this article, you may also be interested in:

• New Master of Advanced Studies (MAS) in architecture and digital fabrication at ETHZ
• Watch flying machines weave a rope bridge you can walk on
• Architectural robots: The shape of the robots that will shape your home

   

• Swiss to invest almost CHF30 million in digital fabrication research over next 4 years

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Transcript below.

In this episode, Audrow Nash speaks with Brad Nelson, Professor at ETH Zurich, about his research regarding micro and nano robotics. They discuss many of Nelson’s projects: retinal and heart surgery, crystal harvesting, and robots with simulated flagella for mobility.

The video below shows some of the research discussed during the interview.

Brad Nelson 

Brad Nelson has been the Professor of Robotics and Intelligent Systems at ETH Zürich since 2002, where his research focuses on microrobotics and nanorobotics. Fundamentally, he is interested in how to make tiny intelligent machines that are millimeters to nanometers in size.

He studied mechanical engineering at the University of Illinois and the University of Minnesota, worked as a computer vision researcher at Honeywell and a software engineer at Motorola, served as a United States Peace Corps Volunteer in Botswana, Africa, and then obtained a Ph.D. in Robotics from Carnegie Mellon University. He was an Assistant Professor at the University of Illinois at Chicago and an Associate Professor at the University of Minnesota before moving to ETH.

Links:

• Download mp3 (18.4 MB)
• Subscribe to Robots using iTunes
• Subscribe to Robots using RSS
• Link to the Muli-Scale Robotics Lab

Transcript

Audrow Nash: Hi, can you introduce yourself?

Brad Nelson: My name is Brad Nelson. I am a professor of robotics and intelligence systems at ETH Zurich. I’ve been there for almost 13 years now.

Audrow Nash: Can you give me the big picture goal of your research?

Brad Nelson: The focus of our research is micro and nano robotics. We’re trying to understand how to make machines as small as we can and, along the way, we develop fabrication techniques to manufacture them. We look at ways to make them move, we look at applications for them and try to put that all together. We try to move the technology from fundamental research into a spinoff, a clinical application or something we might license to another company.

Audrow Nash: Just how small are these machines?

Brad Nelson: We work on things that are millimeters down to nanometers in scale. One of the things we’ve worked on for several years now is a device we call an artificial bacterial flagella. It’s about the size of a bacteria, maybe 15 or 20 microns long. You could fit about three billion in a teaspoon. They’re very tiny, you put five of them head to head and they might be about the width of a hair.

These are the smallest things we can see with optical microscopes. But then we also do a lot of work on nano fabrication with nano wires and nano structures, where you can’t see them, even with optical microscopes, so we need electron microscopes. Some of these structures will go down to 30 nanometers in diameter. And then we have things we put in the eye that are perhaps a millimeter or two long.

Audrow Nash: What are some applications of those?

Brad Nelson: One thing we’ve been working on has been retinal surgery; ways we can deliver drugs to specific locations on the retina, to target diseases such as age related macular degeneration or diabetic retinopathy. We’ve also realized that some of the technologies are not just for moving micro robots, but can move small catheters and endoscopes that you might want to put into the body.

We also work on how we might guide, not just untethered autonomous machines but small endoscopes or catheters, into the heart or the brain.

Audrow Nash: Do you see applications outside of the medical field?

Brad Nelson: We do. Drug discovery is one. One of the methods for discovering drugs is to first develop models of proteins. In the human DNA, we know the atomic sequence of protein molecules but we still have to understand the structure.

In structural biology, one of the main methods used to determine the shape of these tiny little molecules is to isolate proteins and crystallize them – grow them into tiny crystals. We’ve developed some of our micro robotic technology to handle these tiny crystals and to automate the process of retrieving them from the “mother liquor” and place them on a loop. That device is then immediately freeze dried, with the protein crystal on it, and then put into a high-energy x-ray beam. The structural biologist can infer the shape from the x-ray diffraction pattern.

It’s a long process but nobody has been able to automate it, up to now, so we think we have a solution there.

Lately, we have also been thinking of ways we can use these devices to create a catalytic reaction to treat wastewater.

Audrow Nash: Catalytic reaction?

Brad Nelson: To photo catalyze pollutants, for instance, and take toxins that are in the environment and degrade them into harmless substances. The idea is to put micro robots into polluted water, to treat and clean it.

There are also sensing applications: we can put micro robots into an environment and look at what chemicals are there, what kinds of substances that we want to get rid of. So we can use them as sensors to monitor the environment.

Audrow Nash: To understand this a little bit better I would like to talk about a few of your projects. To begin with, controlling micro robots with five degrees of freedom, can you describe that?

Brad Nelson: One of the first challenges we have is how to make small things. There’s micro fabrication technology and we borrow from the semiconductor industry; to make small machines, it’s the same technology as for making computer chips.

The second problem is how to make these small machine move: what kind of technologies can you use? Is there some kind of chemical reaction? Can you use lasers to deliver energy? The community has kind of settled, recently, on the use of magnetic fields, so you generate fields externally with electromagnets.

Basically, you wrap a wire around some kind of an iron core and, as you generate the electric current around it, you can create weaker and stronger magnetic fields. By changing their strength, we can exert forces that work on these small devices if they’re made of magnetic material.

We first started doing this over a decade ago with just two degrees of freedom, making it move on a surface. Then we started working on three degrees, to make things move in the X to Y and Z coordinates and to rotate.

Then we turned to five degrees of freedom motion. We realized we were going to need several electromagnets for this. We did a lot of numerical simulations on a computer to understand where the best place to put these magnets was, and the best way to control them. We realized we needed at least eight electromagnets. We built a system we call the OctoMag, so that we can very precisely control the current in each magnet and move small things with it.

Audrow Nash: Why do you need eight electromagnets for five degrees of freedom?

Brad Nelson: That’s something that we never quite understood until just recently. One of my post docs is working with me on this. Looking at the math, he realized that we can actually prove mathematically that eight is the minimum. We knew people who built systems that only had six magnets and they were having issues.

Magnetic fields can generate a force or a torque on something. The torque is like a compass needle on a magnetic field; we always know it’s going to point to the north and align itself with the earth’s magnetic field. Just by taking our field and rotating it, we can get other things – the magnetic particles, structures and micro robots – to rotate too, to align with the field.

Forces are a little more complicated because they require a special gradient of the field. The field has to be getting stronger in a direction, so that the micro robot moves in that direction. It’s with this coupling that the math gets a little complicated; you see a dependency between how you generate the gradient and the magnetic field.

It means that, although with five degrees you might think you just need five electromagnets, you can’t generate obituary gradients and fields at the same time. You need to add more electromagnets, and the question is: what’s the minimum? For our problem, it happened to be eight. The theoretical results are about to appear online now. It’s fascinating. People have been trying to understand how fields are generated since the 1800s, the 1700s even, and we’re still discovering new things. I think that’s going to help spur us on to new ideas and ways of making small things move, which is really the ultimate goal of what we’re trying to do.

Audrow Nash: This technology has gone into your startups. In addition to using small robots for crystallography, can you talk a bit about having a viable business model in research for this? Did you begin the research with a plan to market it?

Brad Nelson: I became a professor in 1995, so 20 years ago. My goal then was just to do interesting research, write good, grand proposals to get funding and to publish papers that people wanted to read. I think we’ve been successful in that.

Then, along the way, we started to get interested in getting our technologies out into the real world and that is a tremendous challenge. It’s one thing to have a research result to publish and another to actually develop a technology that people want to pay money for and use, and to help improve peoples’ lives in some way.

As I’ve developed my research agenda over the past 20 years, I started to think more carefully about potential business plans that might make sense. In biomedical, it’s clear you need to have patents and to be aware of what the patent landscape is. Even now, with some of our Masters projects, we will often go and just look at what patents are out there in this area.

If somebody like Siemens or Phillips already has a patent in an area, it can block the technology. It doesn’t make sense to go down a route where somebody has the IP locked up and, even if you do develop the new technology, there’s no chance of getting it out. You start to think in terms of: can you own, or do you have the potential to own, some important intellectual property in the area and develop it. You also consider, as you’re working on things, what potential therapies might this benefit and does it make sense, from a business standpoint, to develop these therapies.

Audrow Nash: What do you mean by therapies?

Brad Nelson: Well, for instance, one of our startups is called Aeon Scientific. They took our technology and they’re starting to look at some uses for magnetic fields. They looked at a lot of different areas and one thing they realized is that, with the aging population, more and more people need a particular heart procedure to treat a condition called Atrial Fibrillation, where your heart doesn’t beat properly; the electric signals don’t propagate through the heart.

Audrow Nash: It’s too fast or too slow or irregular?

Brad Nelson: Too fast or too slow or it doesn’t synchronize properly and so electrophysiologists and cardiac surgeons have discovered that, if they do a little therapy within the heart, they can reset it. People see potential to help a lot of people, but that also means potential to make money. It takes a tremendous investment to get this technology into the clinic. To justify that investment, you’ve got to realize a return on it. For that therapy, it makes sense.

Another therapy we’ve thought about is bronchoscopy, putting some of these devices into the lungs, particularly in premature infants, and trying to see which portion of their lung might be collapsed. That’s a therapy we’re interested in. The business model isn’t so convincing there; people just don’t project the potential number of cases that would justify the investment. That’s one of the reasons you’ve got funding agencies to enable you to progress further.

Audrow Nash: You mean funding agencies that fund research that’s not as in demand?

Brad Nelson: They fund research where the business model may not be clear. Although there are benefits, business investors may not find it persuasive, but it’s certainly going to be able to treat patients. We try to balance the two. We’re always trying to weigh up the problems we’re working on, the ones that have the potential to make a big impact. There are a lot of ways to measure this. One of these is the business case.

Audrow Nash: Going back to steerable catheter design with Aeon Scientific. So, you insert a catheter and that goes in through the arm or the groin or the neck, correct?

Brad Nelson: It goes through the femoral artery, near the groin. It enters the right chamber and then you can move over into the left chamber. You can get into all four chambers with this.

Audrow Nash: It has a flexible end that you direct using similar principles to the five degrees of freedom of manipulating small devices?

Brad Nelson: Yes, so the end of the catheter – the last few centimeters – is very floppy. At the very end is a permanent magnet. We can control its position and its orientation in the heart very precisely. We use that to deliver radio frequency therapy to ablate, to create this transmural ablation to stop electric signals from passing though certain areas of the heart.

Audrow Nash: The permanent magnet that’s at the end of the catheter is much bigger than some of the previous work you’ve done. Does the control of these magnetic robots scale?

Brad Nelson: It tends to scale well, although that needs a bit of explanation.

Generally, as devices get larger, magnetic fields can scale more favorably. But as they get smaller, it’s different. Magnetic forces and torques are a function of the volume of the magnet. Whenever you have something that depends on volume, as it gets smaller that’s not good, because if something is a cubic meter and then goes down to 10 centimeters, the size is decreased by just a factor of 10, but the volume has gone down by a factor of 1000. You’re getting these incredible decreases in the forces you can generate, so then we have to rethink our strategies. That’s where we’re inspired by nature – bacteria, for instance. We look at why E. coli swim with a rotary motor and use a flagella.

Audrow Nash: Describe the flagella a bit.

Brad Nelson: When Howard Berg [a professor of physics and molecular and cellular biology at Harvard] was in Colorado in 1973, he discovered that some bacteria, like E. coli and salmonella, have this little flagella. It’s a hair-like structure. People would look at it under a microscope and they couldn’t tell exactly how it moved. What Howard discovered, which surprised a lot of people, was that there was actually a rotary motor on this bacteria. People were astounded by that discovery. It was the first example of rotational motion in nature.

Audrow Nash: So it moves forwards in a similar way as a screw into wood?

Brad Nelson: Yeah, it’s like a screw, so it rotates this hair, this flagella, into a kind of helix shape, like a coil, and it propels itself that way. There’s a lot of physics, a lot of biology about why this works so well at these scales, that’s fascinating. How did nature evolve this kind of a structure? That’s a wonderful question.

We looked at it and realized that we can’t build that motor. It’s about 45 nanometers in diameter and it’s got 30 or 40 parts that are made out of proteins. What we could make, using some recent developments in nanotechnology, is these tiny little screws. Then we realized, if we put little magnets on the screws and rotated that field, we could get them to turn just like the E. coli flagella do. So they started propelling themselves, moving in fluid. That was in about 2007. We were surprised how well it worked and, as we understood the physics and the mathematics in the fabrication issues behind it, it’s been a very thrilling, rewarding area of research.

We’re always discovering something new and we’ve recently published a couple of papers. In one of them we’ve put DNA on these structures and we’ve demonstrated that, as we swim them near cells, we can get the cells to take up the DNA and then do gene transfection and express these.

The DNA would be coded for a particular florescent protein, so then the cells would express it and we can watch the cells start to light up. It demonstrates that we can target individual cells and do gene transfection with them.

In another project we’ve taken 80,000 of these ABF – the Artificial Bacteria of Flagella. We took this huge swam and injected it into the peritoneal cavity of a mouse and we’ve tracked it swimming within it. That paper’s recently come out.

Audrow Nash: What applications are there in that?

Brad Nelson: What we’re trying to do is demonstrate how we could potentially load some kind of drug on to these, and then target a particular location in the body. We demonstrated that we can load DNA and do transfection, then we demonstrated that we can move swarms of them and target particular locations, in this case in a mouse. Then, eventually, the furthest steps would be putting some kind of a drug that may treat a condition on there, and trying to target some very specific location, maybe a tumor in the body, and getting them to swarm around it and deliver the drug in a very localized area.

Audrow Nash: What do you think is the future and timeline of micro and nano robots?

Brad Nelson: I really think the field has made tremendous strides in the past 10 to 15 years. There are so many interesting problems and so many results that surprise me. I certainly think that within the next decade we’ll see these devices in clinical trials.

If we’re looking at medical applications, the first people we have to get interested in this are the doctors, the people who are really going to use it. They have to understand what the potential is and they have to understand what conditions could be treated with it. They have to get excited about it and be willing to work with us on it.

The first thing is you get doctors involved. Doctors have spent some of their valuable time with us on this. It takes tremendous investment and resources to get these things pushed through, to get all the engineering done properly and the FDA regulations, or whatever medical regulations need to be followed. That means you need business people; you need investment, so you need to convince business people too.

You’ve got to bring together, not just the engineers and scientists, but also the medical doctors and the business side. That’s what always makes it difficult to predict exactly how long this will take. With the right resources we can move very quickly, but not everybody’s vision is in alliance, initially. I certainly hope and expect that within less than a decade we’ll see applications in the clinics. I think, with this kind of thing, once it gets going, more and more things – things we can’t see right now – will start to emerge. I’m very confident about that.

Audrow Nash: Thank you.

Brad Nelson: Thank you very much.

All audio interviews are transcribed and edited for clarity with great care, however, we cannot assume responsibility for their accuracy.

If you like this post you may also enjoy:

• Micro-robotics and medicine: Interview with Toshio Fukuda
• Minimally-invasive eye surgery on the horizon as magnetically-guided microbots approach clinical trials
• Better micro-actuators to transport materials in liquids
• Crowdsourcing new strategies for cancer treatment: Towards swarming nanobots
• Robots Podcast: Nanosystems

The first DroneApps Forum in Lausanne, Switzerland, recently assembled 150 drone professionals from Europe, the US, Japan, and Australia for a two-day exchange of ideas. 

European, Japanese, and US drone manufacturers were in attendance, with many reporting on the number of flight hours logged by their customers and their market shares. They pointed out current challenges, including the urgent need for more situational awareness for inspection tasks with multicopters, and the need for higher endurance and higher payload for monitoring with small fixed wing planes. 

Operators, including Robin Murphy (Roboticists Without Borders, Center for Robot-Assisted Search and Rescue), Cyberhawk, COWI, and the SNCF (French national railway company), presented case studies that highlighted the benefits and downsides of using drones to replace existing solutions. 

Regulators and legal professionals discussed the current state of legislation in the UK, France, Switzerland, the US, and Canada. They openly shared their concerns related to privacy, criminal activity, and liability — but also pointed out the importance to stay level-headed in spite of anxieties and fears. 

“Not every new technology has to result in a hectic activity of regulators.” – Peter Müller 

Discussions also covered software providers, including those providing aerial image processing such as Pix4d, Acute3D, and Agisoft. 

A number of the presentations are available here.

The picture emerging from this particular 2-day snapshot of the state of the industry showed what’s working today (e.g., fixed wing drones for surveying in the mining industry) and what isn’t (e.g., multicopters for autonomous inspection). Autonomous flight through airspace without obstacles seems to be well understood and operators have logged thousands of hours. Similarly, autonomous takeoff and landing of small fixed wing planes seems to be working remarkably well. However, autonomous flight near obstacles, such as that required for most inspection tasks, remains a challenge without adequate solution across all platforms. 

One key take-away from the forum was the stark contrast between doers, who constantly fly, and talkers, who stage drone flights for marketing and PR to help sell their vision. (Don’t get me wrong — I think both are valid ways to boot-strap a new business, each with its own risks.)

Some other key take-aways from this particular event: 

• Innovation is led by startups, some of which have already accumulated significant operational experience. Major established players like Lufthansa or Swiss WorldCargo are lagging far behind. 
• Most hardware and electronics seem to be coming out of Europe. Most high-level software, apps, and cloud applications seem to be coming out of the US. 
• Drones are used much more to improve current solutions than to pioneer new application areas. 
• In spite of all the media hype, it’s still very early days for commercial drones. 

ETH Zurich, 2015.

Using quadrocopters and some rope, researchers have woven together a bridge strong enough to walk across.  Made at the ETH Zurich Flying Machine Arena in Switzerland, the bridge joins two scaffolds, and is the first full-scale load-bearing structure autonomously built by flying machines. The feat represents one more step in the field of robotic aerial construction [1, 2].

Except for the metal scaffolding at either end of the structure, the bridge itself consists exclusively of Dyneema rope, a tensile material with a low weight-to-strength ratio that makes it ideal for aerial construction. Weighing just 7 grams per meter, a 4 mm diameter Dyneema rope can sustain up to 1300 kg. The 7.4 m long bridge uses various rope techniques – knots, links and braids [3] – and has a total rope length of about 120 m.

How it works

The project was developed at the Flying Machine Arena [4], a research and demonstration platform for aerial robotics. The arena is equipped with a motion capture system that provides vehicle position and attitude measurements for the small custom quadrocopters. An offboard computer runs the algorithms and sends commands out to the flying machines via a customized wireless infrastructure.

Flying machines cooperate to create a braid and brace the structure together.

Before construction begins, the location of the scaffolding is measured and input to the system. Once the anchor point locations for the rope are known, all the connections and links of the bridge’s primary and bracing sections are — without human intervention — autonomously woven and secured into place by the quadrocopters, which are each equipped with a motorized spool that allows them to control the tension of the rope.

A quadrocopter equipped with a motorized spool for rope deployment.

A plastic tube guides the rope to a release point located between two propellers. The system estimates the external forces and torques exerted on the quadrocopter by the rope during deployment, and takes this into account in order to ensure that the quadrocopters behave as desired [5].

The researchers then walk across the bridge to demonstrate its load-bearing ability.

Once the bridge itself is constructed, stabilizers are added to make it easier for a person to cross. Because there are no sensors to detect the rope’s configuration, the locations of the narrow openings of the bridge must be measured and input to the system, which then adapts the quadrocopters’ trajectories in order to weave the stabilizers.

The team also developed a series of computational tools to help identify and design the kinds of novel structures that are buildable using flying robots. Using these tools, the researchers can simulate their designs, determine feasible construction sequences, and evaluate the structure before they begin building [6].

More information and related publications can be found on the project websites:

• http://www.idsc.ethz.ch/research-dandrea/research-projects/aerial-construction.html
• http://www.gramaziokohler.arch.ethz.ch/web/e/forschung/240.html

Credits

Aerial Construction is a collaboration between the Institute for Dynamic Systems and Control and Gramazio Kohler Research at ETH Zurich, Switzerland, 2015.

Researchers: Federico Augugliaro, Ammar Mirjan, Fabio Gramazio, Matthias Kohler, and Raffaello D’Andrea.

Related work

[1] F. Augugliaro, S. Lupashin, M. Hamer, C. Male, M. Hehn, M. W. Mueller, J. Willmann, F. Gramazio, M. Kohler, and R. D’Andrea. “The Flight Assembled Architecture Installation”, IEEE Control Systems Magazine, 2014

[2] A. Mirjan, F. Gramazio, and M. Kohler, “Building with Flying Robots”, FABRICATE: Negotiating Design and Making, 2014

[3] F. Augugliaro, E. Zarfati, A. Mirjan, and R. D’Andrea, “Knot-tying with flying machines for aerial construction”, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2015

[4] S. Lupashin, M. Hehn, M. W. Mueller, A. P. Schoellig, M. Sherback, and R. D’Andrea, “A platform for aerial robotics research and demonstration: the flying machine arena”, Mechatronics, 2014

[5] F. Augugliaro and R. D’Andrea, “Admittance control for physical human-quadrocopter interaction”, European Control Conference, 2013

[6] A. Mirjan, F. Augugliaro, R. D’Andrea, F. Gramazio and M. Kohler,” Building a Bridge with Flying Robots”, Robotic Fabrication in Architecture, Art and Design 2016, in press

Article in preparation:

1. Augugliaro, M. Schulz, A. Mirjan, F. Gramazio, M. Kohler, and R. D’Andrea, ”Building a Rope Bridge with Flying Machines”

If you liked this post, you may also enjoy:

• Multiple tethered quadrotors performing high-g, high-speed formation maneuvers 
• Quadrocopter failsafe algorithm: Recovery after propeller loss
• Video: Throwing and catching an inverted pendulum – with quadrocopters
• Quadrocopters learn from prior experience to improve slalom flying

Speakers included Renaud Campion (Robolution Capital), Robin Murphy (Texas A&M University), Dario Floreano (EPFL), Adam Klaptocz (senseFly), Sergei Lupashin (Fotokite), Davide Scaramuzza (University of Zurich), Adrien Briod (Flyability), Patrick Meier, Ben Marcus (AirMap), Chrisoph Strecha (Pix4D), Romeo Durscher (DJI) and many more. Robohub contributors Markus Waibel and Diana Marina Cooper (who participated Law and Regulation panel) in were at the conference; expect follow up coverage of DroneApps soon.

#droneapps Tweets

Transcript included.

In this episode, Audrow Nash speaks with Sergei Lupashin about Perspective Robotics’ tethered flying camera, the Fotokite Phi, which is currently crowdfunding on Indiegogo. The Phi is a portable light weight GoPro-carrying quadrocopter that flies without a vision system or GPS, and instead uses the tension on the retractable tether to determine where it is in space. According to Lupashin, the tethered leash provides a natural, easy-to-learn and accountable interface for controlling the Phi.

https://www.youtube.com/watch?v=aglTWdI-4Bo

Sergei Lupashin

Sergei Lupashin is the founder of Perspective Robotics, the Swiss company behind the Fotokite. Previous to that he worked in aerospace and participated in robotics competitions such as the DARPA Grand+Urban Challenges (autonomous cars). He was chief architect for the ETH Flying Machine Arena, where he enjoyed torturing little quadrocopters until they learned to do flips. He holds a BS in Elec & Comp Engineering from Cornell, an MSc + PhD in Mechanical Engineering from ETH Zurich (topic: aerial robotics) and is a TED Fellow. Sergei is passionate about building devices that are usable and useful in the real world.

Links:

• Download mp3 (14.3 MB)
• Subscribe to Robots using iTunes
• Subscribe to Robots using RSS
• Link to Fotokite Phi Indiegogo campaign

Transcript

Audrow Nash: Hi welcome to the Robots Podcast. Can you introduce yourself to our listeners?

Sergei Lupashin: I’m the founder of Perspective Robotics, a company based in Zurich, Switzerland that is behind the Fotokite, the Fotokite Pro and the Fotokite Phi.

Audrow Nash: Fotokite Phi is currently crowdfunding on Indiegogo. Can you tell me a bit about the campaign and its goal?

Sergei Lupashin: This is our first attempt at building a product for consumers. We started off by building the Fotokite Pro, which is a specialized, more expensive product designed to be used for broadcast. With the Fotokite Phi we have tried to make something much more accessible both in terms of price and usability. It’s extremely portable and it can be used in lots of different situations.

We are trying to raise a minimum of US $300,000 … It’s a hardware product, so you have to build critical mass to make it accessible for a wider audience. It’s a very exciting step for us.

Audrow Nash: Can you describe the Phi?

Sergei Lupashin: I’m holding one in my hands right now … It’s a small quadrocopter that holds a GoPro, and it weighs only 12 ounces – about the weight of a small can of soda.

What’s unique about it is that you control it via tether. You hold onto what is essentially a glorified dog leash with some electronics, and you launch the Phi just by turning it on, giving the quadrocopter a twist, and letting it fly.

Audrow Nash: This doesn’t have the same sensors as most drones. Of course it has an IMU, but you’ve removed GPS, correct?

It’s a different experience from traditional drones because the interface is so physical: you feel pretty much the smallest motions of the Fotokite in the air through the string.

Sergei Lupashin: Exactly. One of the things we use the tether for is to figure out where the Phi is relative to the user. A normal drone does that by having a GPS receiver or having some sort of machine vision to figure out where it is. In our case, we use a tether that is kept under tension at all times. By calculating where that tension force points, the Fotokite actually knows where it is relative to you.

This changes the dynamics of the system because it’s completely self-contained and the whole experience exists around the user. If you are walking down the street, hiking in the mountains or walking down a trail with this thing attached to you, it will naturally follow with you without any special algorithms.

Audrow Nash: Can you tell me a bit about the leash, how it works, how it keeps constant tension?

Sergei Lupashin: When it’s hovering it doesn’t fly straight up; it flies at a small angle and it stays not above you but to the side. The leash is spring-loaded, so the Fotokite produces a bit of extra force to keep the tether under tension.

You can just point the Fotokite in the direction you want to launch it, but once it’s flying, how do you tell it to turn? How do you tell it to move around? We wanted to get away from the concept of having to use a joystick or your smart phone to do that. Inside the leash are electronics that connect to the Fotokite while it’s flying; to control it you hold down the button on the side of the leash and you rotate your wrist. That motion of your wrist – that motion of the leash – is translated into a command for the Fotokite.

Audrow Nash: What kind of commands can you give? Can you have it rotate to look around?

Sergei Lupashin: Yes. Right now there are just two modes of interface. One mode is in-phase rotation. For example, if I want to take a panorama, I would launch the Fotokite straight up and then I would hold down the first button and rotate my wrist. The Fotokite would then rotate in place and capture the full 360 panorama. The other mode lets you control the position of the Fotokite relative to you.

Audrow Nash: The angle?

Sergei Lupashin: Exactly. We usually speak in terms of ‘elevation’ and ‘orbit’. For example, if you look at the stars in the sky, a star has a certain elevation above the horizon. To control the elevation in our case, holding down a button while you move your wrist up and down will move the Fotokite either from a horizontal position to a vertical one (relative to you), or vice versa. It basically controls the vertical angle where it flies.

Moving your wrist in the horizontal plane will cause the Fotokite to orbit, meaning that it will slowly reorient itself around you. If you keep doing this motion, the Fotokite will complete a circle around you at a given elevation.

You can get really neat matrix-style shots of yourself. Or you can use it to do sophisticated shots, using the Fotokite like a flying steady-cam.

Audrow Nash: How long does it take to train someone to use the Fotokite?

The beauty of the system is that there is nothing active in this tether, so you can attach any string to the Fotokite and it will still work just fine.

Sergei Lupashin: It’s a different experience from traditional drones because the interface is so physical: you feel pretty much the smallest motions of the Fotokite in the air through the string.

We did a number of demos for both expert drone users and people who haven’t touched one before. Getting it to fly is surprisingly straightforward: you show someone how to do it, they’ll repeat the motions, and it will work immediately.

To get really unique shots and smooth video requires a bit of skill. The nice thing is, with the tether, you can use your own physical movements to control it and to keep it from crashing into things. It’s a lower stress experience than what you see with traditional drones.

Audrow Nash: Speaking of crashing into things, what happens if it bumps into an object? Or if someone runs into the tether, the tether becomes taught in a different direction, and that tension is released suddenly?

Sergei Lupashin: In terms of bumping into things, we have protective coverings that extend past the motors, so most of the time an object would bump into the protective coverings first. That helps to prevent crashes, and it also helps to give the user confidence in being around the Phi.

In terms of the tether getting caught in things, the beauty of the system is that there is nothing active in this tether, so you can attach any string to the Fotokite and it will still work just fine.

For example, if you’re filming the rooftop of your house and you’re trying to get over to the other side of it, you can actually fly the Fotokite over the rooftop and then get it such that the tether touches the edge so you can sling-shot it over. It will simply use that new fixed point as the new reference point, and this happens naturally.

Explained in words it sounds weird, but just imagine flying a kite where the lift is generated by the kite itself: if you grab the kite string, and someone pulls it away, it will still fly at the same angle – but relative to that new point.

Audrow Nash: Does this mean that you don’t really need the smart leash? Is it just for controlling the Fotokite, so that it rotates and you can change the vertical angle?

Sergei Lupashin: The smart leash is there to make the system complete. Most folks just want to use the system to capture a picture or video. We didn’t want to make them have to go find a string.

The leash is a convenience: it’s nicely built, it has a spring, and it has electronics that allow control.

The Phi’s arms fold up with the propellers on the inside so that you can put it into its tube-shaped carrying case. It’s about the size of a thermos, and you fit it into your backpack.

I should also mention that the Fotokite Phi folds, because in real life, transportation is a major issue. The Phi is pretty unique in that it has a lock mechanism that makes a satisfying click when it locks. And when you unlock it, the arms fold up with the propellers on the inside so that you can put it into its tube-shaped carrying case. It’s about the size of a thermos, and you fit it into your backpack.

Audrow Nash: And everything fits in there?

Sergei Lupashin: Yes, the leash and everything.

Audrow Nash: The tether is very nice from the perspective of controlling the drone. What are some other advantages of using tethers?

Sergei Lupashin: The tether wasn’t actually the original idea.

I was finishing my PhD and looking at different schemes for aerial systems. This was in Raff D’Andrea’s lab – he has been on your podcast as well. We were exploring some different approaches using gestures – with Kinnect for example. But all of these systems were based on machine vision, which is incredibly sensitive to the conditions you are operating in. Sunrise, lens flare, darkness, water – all of these things confuse the system.

The tether completely changed the dynamics of the conversation between the operator, the vehicle and the public. It makes this device much more acceptable in public.

So the question was: how do we get localization and interaction in the most robust way possible? That’s where the idea of the tether came from: it was originally a technical solution to let a flying vehicle figure out precisely where it is relative to you, without relying on sensitive systems like GPS or machine vision etc.

Then, when we made the first demo, it turned out to be a really elegant way to interact with the system. The tether completely changed the dynamics of the conversation between the operator, the vehicle and the public. I think this was actually one of the most exciting moments of this process, because as a technologist you don’t foresee it; you see the tether as a technical solution and nothing else. But then it turns out to also have all of these facets that are not technical, but rather about the experience, and how people see the product.

In the end, the tether changes the Fotokite from being another drone into something that is more of a companion flying device. It’s a very personal device … it’s more like a kite, and people treat it that way.

One parallel is to imagine being at the park and having your dog on a leash versus not on a leash: for some people it’s fine, but other people just get freaked out by dogs that are not leashed. I think we see some of that with drones from a privacy perspective. What we found is that having a tether changes the conversation and makes this device much more acceptable in public.

Audrow Nash: There’s accountability because you can see where the operator is?

Anyone – no technical background required – intuitively understands the chain of responsibility with this device.

Sergei Lupashin: Exactly. Anyone – no technical background required – intuitively understands the chain of responsibility with this device.

Audrow Nash: Can you tell me a bit about how this and similar technology has been used in journalism, for example the Fotokite Pro?

Sergei Lupashin: The original inspiration for the Fotokite came from aerial footage of the Bolotnaya Square demonstrations in Russia in 2011. It was after the federal elections, and it was a big demonstration right in the center of Moscow. The footage was captured pretty much by pure chance from a drone – quite a big drone with an SLR camera. There was this one image, a panorama really … it’s amazing how well it transmitted the scale and atmosphere of the event.

The people who took that footage were very lucky that they happened to have the right equipment; they were professionals so they could do it safely, and they happened to have the right permissions. But we’ve seen many other examples where people haven’t been able to get these perspectives and cover events like this as well as they could have been covered. For example, in Ferguson, Missouri where there was a no fly zone was imposed, which many believe was done to keep the media out.

We also found out that having a physical connection usually changes the regulatory aspect. For example, in Switzerland and France, after some conversation with the regulators we were able to get special rules for tethered devices that are much more permissive than traditional drones. From a regulatory perspective, the usual thought process is focused on safety, whereas privacy is more universal and not usually what they are basing rules on. From a safety perspective, in Zurich for example, it was prohibited for a while to fly drones commercially. The Fotokite was allowed based on the tether and specifically based on the idea that the tether restricts the height of the device.

Many regulators think of how much energy would be dissipated if the device falls in an uncontrollable fall, and there is a magic number of 66 joules … if you fall and it dissipates 66 joules then you are magically unsafe.

Audrow Nash: How much is 66 joules?

Sergei Lupashin: This is potential energy, so it’s Mass X Gravity X Height. Imagine a 6 kg bowling ball falling from about a meter …

It’s a safety margin. With the Fotokite’s tether you can restrict the length of the tether and thus the height, so you can guarantee that under no conditions are you going to exceed that safety limit.

Audrow Nash: So you can only extend to the length of the tether unless you can’t get high enough to possibly generate 66 joules on complete impact?

Sergei Lupashin: Yes, that’s right.

There are other aspects they look at, too, like system robustness. For example, how many subsystems or how many components do you have in your critical loop? How many subsystems are there such that if one of them fails you have an uncontrolled system or a catastrophic failure? In a traditional drone, GPS is usually in that critical loop, as is your radio system, and if you lose your GPS or radio you will crash into something. With the Fotokite, there is no GPS and if the radio cuts out, it will just fly in the same position.

Audrow Nash: How does it look for other countries with these exemptions? For example, do you believe the US will permit tethered drones to fly? Do you think they will give exemptions similar to Switzerland and France?

Sergei Lupashin: It’s very hard to predict which way the US regulations are going to go right now. If you look at the history of it, just over the past few months regulations were proposed that were extremely lenient and permissive. Most recently there has been a massive push over certain events … you’ve probably heard of the person shooting drones down over their property. So it’s really hard to predict.

It’s a challenge since all of this technology is new and people don’t quite know how to differentiate it. For example, what is a tethered drone? If you attach a fishing line to a DJI, is it now tethered? I kid you not that there are commercial products out there for sale that offer exactly this, and they promise to get you around regulations.

We are trying to be proactive and come up with commonsense and observable definitions of what it means to be tethered.

We are trying to be proactive and come up with commonsense and observable definitions of what it means to be tethered. For example, I really believe that the tether has to be loadbearing, meaning that under typical flight it should actually be under tension, and it should be rated for some sort of tension that responds to the vehicle.

Audrow Nash: For a hobbyist or someone that just wants to use the Fotokite Phi to take pictures of themselves, do these regulations mean anything outside of countries that have exemptions for tethered drones? Or is it only for commercial use and journalism that the regulations apply?

Sergei Lupashin: Regulations generally apply to commercial use, but there are exceptions specifically generally cities, populated centers, and in the US national parks. If you go for a hike to the Yosemite or Yellowstone National Park in the US, for example, you can’t use a drone right now. These are the kind of the frontlines where we’re going to see how consumer drones get regulated in the future.

Audrow Nash: Going back to the Phi, how does the tether affect battery life?

Sergei Lupashin: In the Pro we use the tether to supply power, so we can fly forever. In the Phi we couldn’t do that because of cost and complexity, so we use a standard one-port battery. The trick there is that, since you’re producing extra tension to keep the tether taut, you are wasting a tiny bit of battery life, but on the other hand, if you imagine how a kite actually uses the wind, you could be using a less than normal power to stay afloat.

The current prototypes fly for around 7-10 minutes. For the production units, we are aiming for 15 minutes of typical flight time. The battery is swappable in the field, so you always have the option of replacing it.

Audrow Nash: How did you decide to move from a journalism drone – the Fotokite Pro – to a consumer drone with Fotokite Phi?

Sergei Lupashin: With the Fotokite Pro we realized after talking to existing drone users that the tether has a unique advantage especially in the niche of live reporting. In journalism you typically want to operate next to people and next to something that’s happening, and you don’t want to add tension to that situation. It’s a very unique niche where the tether makes a huge difference. The powered tether is important because journalists can keep the device afloat and not worry about battery life.

But we always wanted to build something a wider reach, and a few months ago we finally decided it’s now or never, because everything is developing very quickly. The Phi is is a big experiment for us to see how well we can use the tether to build a new user experience.

A lot of people see the Phi for the first time and they think it’s just a quadrocopter on a string, but the deeper story is to look at the engineering behind it, using the tether as a different interface approach.

A lot of people see the Phi for the first time and they think it’s just a quadrocopter on a string, but the deeper story is to look at the engineering behind it, using the tether as a different interface approach.

Audrow Nash: Is this a way of addressing the interaction bottleneck with robotics technology?

Sergei Lupashin: That’s right. Have you tried reprogramming your alarm clock lately? [laughs]

In robotics labs we tend to come up with ridiculously complex systems. I’m sure they can do a lot in principle, but they are very difficult to interact with. I think this somehow echoes with many robotics products that have already come out. An example of that is in Japan when the Fukushima incident happened. Arguably Japan has some of the most advanced robotics, especially for search and rescue, anywhere in the world. But they really struggled to make a difference in that situation. And I think a lot of problems are because of interaction, because of training, and because of the complexity of the systems.

The inspiration for the Phi is really to try to cut across that and come up with a smooth and low-friction user experience, where even someone who has never touched robotics could be shown how to use this device and they could naturally take it, use it themselves, and feel confident and empowered by it.

Audrow Nash: Thank you.

Sergei Lupashin: Thank you.

All audio interviews are transcribed and edited for clarity with great care, however, we cannot assume responsibility for their accuracy.

T=0 hours. AtlantikSolar team hand launches the AS-2 at 09:32 on July 14th, hoping to set a new world record.

Two weeks after demonstrating AtlantikSolar’s first 24-hour flight, the fixed-wing team of ETH Zurich’s Autonomous Systems Lab has reached another milestone: 81.5 hours and 2316 km of continuous flight for its 6.8kg AtlantikSolar 2 Unmanned Aerial Vehicle (AS-2). This breaks the flight endurance world record in its class.

The AS-2’s fifth test flight:

• sets a new world record for the longest ever demonstrated continuous flight of all aircrafts below 50kg total mass, and is also the longest-ever continuous flight of a low-altitude long-endurance (LALE) aircraft (the previous record being a 48-hour flight by the 13kg SoLong UAV ).
• is the second-longest flight ever demonstrated by an Unmanned Aerial Vehicle (behind Airbus Space’s 53kg Zephyr 7)
• is the third-longest flight ever demonstrated by a solar airplane (behind Airbus Space’s 53kg Zephyr 7 and the 2300kg Solar Impulse 2)
• is the fifth-longest flight ever demonstrated by any aircraft (both manned and unmanned).

In addition, the flight is a first important milestone to verify the UAV’s ability to stay airborne for multiple days while providing telecommunication services in large-scale disaster-scenarios, or live-imagery during industrial sensing and inspection missions.

T=2 hours, shortly after launch. Weather conditions: occasional clouds, and strong winds up to 40km/h.

Flight Summary

The flight was performed at the Rafz, Switzerland, RC-model club airfield from July 14^th-17^th, of which the first three days provided sunny conditions. Take-off was performed via hand-launch at 09:32 on July 14^th, and after 2316km and 81.5 hours – 4 days and 3 nights – of flight, the aircraft landed safely and with fully charged batteries at 18:56 on July 17^th. The fully charged batteries would in theory have enabled to continue the flight through the night again. With the exception of take off, the aircraft was in fully-autonomous operation 98% of the time, and less than 2% in autopilot-assisted mode via its Pixhawk autopilot.

T=8 hours. Monitoring the aircraft and its energy generation and storage system. The batteries are fully charged.

The long-endurance flight provided helpful insights on the flight performance: The average level-flight power consumption in calm conditions (e.g. during night) was shown to be between 35-46W. Maximum power input throuh the 88 SunPower E60 cells during the day was around 260W. With this performance data, the aircraft managed to fully charged its batteries (100% SoC) at around 13:05 local time, before the time of maximum solar radiation (solar noon, occurring around 13:30). After flying through each of the three nights, the aircraft on average reached a minimum state of charge of 35% at around 07:45 local time, showing sufficient energetic safety margins for worse environmental conditions (such as longer nights, cloud cover or winds).

The flight also subjected the aircraft to a wide range of environmental conditions. Among them were thermal updrafts during the first evening/night (causing a remaining state of charge of 40% ), and downdrafts during the second night (remaining state of charge 32%). The last hours of the flight were marked by upcoming thunderstorm clouds and the strongest winds – up to 60 km/h – the aircraft was ever subjected to. Although the ground station was partially damaged by the winds, the airplane could be landed safely in autopilot assisted mode once the winds had calmed down.

T=41 hours. Drawing circles in the night sky using the onboard position indicator lights.

T=81 hours. Thunderstorm clouds and winds up to 60 km/h make landing the AS-2 a challenge.

T= 81.5 hours. Landing.

T=81.5 hours. A happy AtlantikSolar team after a record flight.

Future work

Having demonstrated the multi-day endurance capability of the bare UAV platform, the AtlantikSolar UAV project will now focus on extended endurance flights with payloads including optical and infrared cameras, and atmospheric sensors. These payloads will also be carried during a long-endurance and long-distance mission of more than 12 hours and 400km that is planned for later this year in the Brazilian rain forest.

Further information

Detailed design and technical information on the UAV platform can be found in “Oettershagen P, Melzer A, Mantel T, Rudin K, Lotz R, Siebenmann D, Leutenegger S, Alexis K, Siegwart R (2015), A Solar-Powered Hand-Launchable UAV for Low-Altitude Multi-Day Continuous Flight. In: IEEE International Conference on Robotics and Automation (ICRA)”

Acknowledgements

This research was funded through ETH Zurich’s internal resources, private supporters, and the European Union FP7 Search-And-Rescue research projects ICARUS and SHERPA . In addition, multiple project partners and collaborators have contributed towards making this important milestone possible, and we’d like to thank all of them for their various and ongoing support. Finally, we are grateful towards the Rafz model aeroplane club for providing the airfield and the Aero Club Asas da Planície (Portugal) for providing the backup airfield!

Pilots: Rainer Lotz, Adrian Eggenberger, Philipp Oettershagen, Bartosz Wawrzacz. Development and Operations Team (Autonomous Systems Lab): Philipp Oettershagen, Rainer Lotz, Amir Melzer, Thomas Mantel, Bartosz Wawrzacz, Konrad Rudin, Thomas Stastny, Raphael Schranz, Jan Steger, Lukas Wirth, Dieter Siebenmann, Dr. Stefan Leutenegger, Dr. Kostas Alexis, Prof. Dr. Roland Siegwart.

The flight was performed at the Rafz RC-model club airfield in excellent sun conditions. After take-off at 11:14, with batteries charged to 57%, the aircraft was quickly setup to follow an efficient and fully-autonomous loitering path, which allowed a completed battery-charge by 14:08 o’clock.

The midday and afternoon were characterized by strong thermal up- and downdrafts, but enough power was generated by the solar panels to keep the batteries full. Their discharge started only when the sun slowly went down at around 19:30.

The night flight provided calm conditions, with the autopilot keeping the aircraft stable despite horizontal winds of up to 5m/s, and the safety pilots keeping a good eye on the aircraft using its position indicator lights. Flying at an average airspeed of 8.4m/s (the point of minimum sink rate) and an average power consumption of 43W during the night, the aircraft received first sun at around 5:50 o’clock, and maintained a minimum charge of around 35% until the solar modules regenerated enough power to stay airborne.

After 24 hours of continuous flight, the aircraft had recharged its batteries to 84%, a significantly higher state-of-charge than the day before. The batteries were in fact fully charged by 12:43 o’clock – one hour and twenty-five minutes earlier than the day before.

AtlantikSolar landed safely at 15:35, thereby setting a new Swiss endurance record for unmanned solar-powered flight, and improving upon the previous internal record (ASL’s Sky Sailor) by a over an hour.

The project’s next goal is to extend the flight duration to more than 80 hours (3 days), in order to beat the old endurance record for solar-powered UAVs below 20kg (48h flight by the 13kg SoLong UAV in 2005) by more than a day. If it is able to achieve an 80-hour flight endurance, the 7kg AtlantikSolar would be the third-longest flying aircraft in the world, only behind Airbus Space’s 53kg Zephyr and the 2300kg Solar Impulse 2.

We’d like to thank everybody who made this flight possible — including all project partners and collaborators, the Rafz Model airfield club, and our safety pilots — for working so hard and making this big step in the project possible.

The AtlantikSolar project was developed at the Autonomous Systems Lab at ETH Zurich. 

Tailsitter in the Flying Machine Arena. Source: Robin Ritz, Institute for Dynamic Systems and Control, ETH Zurich.

In August 2014 Google [x] announced that they had been secretly developing a drone delivery program to rival Amazon’s Prime Air. Called Project Wing, the system was based on a mechanically simple “tailsitter” design – a hybrid vehicle that takes off vertically like a multirotor but is also able to fly horizontally like a fixed-wing airplane. Following field tests, however, Google scrapped the design, saying that it was difficult to control and didn’t perform well in high winds. Since then, researchers at ETH Zurich have developed a new algorithm for robustly controlling a tailsitter flying machine in hover position. Using the algorithm, the tailsitter is able to recover from any orientation, including upside down. ETH has not yet demonstrated its algorithm in real-world conditions (e.g., high winds, GPS localization, different payload distributions). However, given the robustness of the solution shown in the video, perhaps Google should not dismiss the tailsitter design too quickly for its next design iteration.  

– Robohub Editors

A tailsitter provides hover capability by pointing the nose and thrust direction upwards. For fast forward flight, the vehicle tilts to a near-horizontal orientation, resulting in efficient lift production due to the conventional wing design. Compared to other fixed-wing, hover-capable aircraft such as tiltrotors and tiltwings, the major advantage of a tailsitter is its mechanical simplicity: no mechanism for changing the direction of the propulsion system has to be added, saving weight and increasing reliability.

The algorithm demonstrated in the video is based on Optimal Control. Optimal trajectories for a set of initial orientations are precomputed and the corresponding initial desired body rates are stored in a small lookup table (500 entries). An outer control loop running at 50 Hz reads the desired body rates for the current orientation from the lookup table, and feeds them to an inner control loop. The inner control loop runs at 1000 Hz and tracks the desired body rates with the two propellers and the two flaps using feedback from a rate gyroscope. The resulting real-time computational complexity is extremely low.

Tailsitter’s propellers and motors. Source: Robin Ritz, Institute for Dynamic Systems and Control, ETH Zurich.

The propellers are driven by brushless Hacker A05-13S motors that are attached to the wings by 3D-printed mountings. While the vehicle is hovering, it is crucial that a large part of the flaps are within the propeller-induced airstream, in order to keep the flaps effective and the system highly maneuverable. The motors are controlled by ZTW Spider 12A ESCs, which run custom SimonK firmware that enables a fast response to thrust set point changes. Since the custom SimonK firmware is tuned for the fastest possible response, the motor controllers get quite hot and are therefore placed in the propeller airstream for cooling.

Tailsitter’s underbelly. Source: Robin Ritz, Institute for Dynamic Systems and Control, ETH Zurich.

Two radios are attached on the bottom side of the vehicle; a WiFly module for high-bandwidth telemetry, and a low-latency, frequency-hopping 2.4 GHz radio link that receives the control commands from the ground station. The total system latency including the motion capture system and the radio link is around 35 milliseconds.

Tailsitter’s flaps. Source: Robin Ritz, Institute for Dynamic Systems and Control, ETH Zurich.

The flaps are actuated by MKS DS65K servos providing a fast response on flap angle changes. The flaps of the original frame are designed for fixed-wing forward flight and do not provide enough control authority for the hover flight regime. Therefore their area is enlarged by carbon fibre sheets. This increases the effectiveness of the flaps by a factor of four. The maximum flap deviation is 30 degrees.

Tailsitter’s flight management unit (FMU). Source: Robin Ritz, Institute for Dynamic Systems and Control, ETH Zurich.

A Pixhawk PX4 Flight Management Unit (FMU) runs the onboard control loop that tracks the desired body rates using a rate gyroscope which is also provided by the FMU. Safety routines that switch off the actuators if the vehicle does not receive control commands anymore or if the battery voltage is too low are also implemented on the FMU.

The algorithm is presented in research paper “A Global Strategy for Tailsitter Hover Control”, submitted to International Symposium on Robotics Research (ISRR), 2015.

Researchers
Robin Ritz and Raffaello D’Andrea
Institute for Dynamic Systems and Control, ETH Zurich
Flying Machine Arena

Technical details
Frame: Robbe Mini Wing RC styrofoam airframe
Electronics: Pixhawk PX4 Flight Management Unit
Battery: Thunder Power RC G6 Pro Lite 25C LiPo 350mAh 2S
Motors: Hacker A05-13S
Motor controllers: ZTW Spider 12A ESCs with SimonK firmware
Propellers: 5×3 GWS EP-5030
Flap servos: MKS DS65K
Infrastructure: Flying Machine Arena

• Multiple tethered quadrotors whip around a pole together at high speeds 
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• Three new quadrotor videos demonstrate agile control and the power of machine learning
• Video: Quadrocopter learns from its mistakes, perfects slalom air racing

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

The foldable quadrotor is small enough to fit in a hand (Photo: LIS, EPFL, NCCR Robotics).

The use of robots to find victims after natural disasters is fast becoming commonplace, with well documented cases where robots have been sent into areas too dangerous for rescue workers.  While the issues surrounding robustness, control and autonomy are frequently cited as key areas for research, a  team from LIS, EPFL and NCCR Robotics is working on another important aspect, how to make flying robots easily transportable and quick to deploy.

In a paper, which will be presented at the International Conference on Robotics and Automation (ICRA) 2015, the team describes how they made a quadrotor with rapidly self-deploying, folding arms. Foldable aerial platforms currently use either beams or detachable appendages (e.g. DJI spreading wings series and SenseFly eBee), which require manipulation by the user, slowing the process down and introducing the possibility of human error. The presented prototype has self-deploying arms that go from completely stowed to ready-to-use in 0.3 seconds, meaning that multiple drones can be utilized at once in a very short period of time.

The origami arms are stored using a system of strategically placed magnets, which can use the torque and thrust generated by the propellers to break the magnetic seal, thus allowing the arms to deploy when the quadrotor is switched on. In order to make use of such a simple mechanism, the design team carefully considered the placement of the folds in the arms; to take advantage of the propeller’s torque, folds are parallel to the its axis.

The origami structures that make up the arms allow them to fold around the central core, reducing its volume to about a third of commercial quadrotors of a similar weight. To make the origami structures, the arms are constructed from a 0.3mm layer of fiberglass over Icarex, a lightweight and inextensible fabric. Two vertical folds in the 2D structure allow the arms to lie in the wrapped configuration. When the motor begins, the action of the propellers forces the magnets apart and allows the arm to straighten in its flat configuration, whereupon a second set of magnets attract and pull the horizontal fold (down the centre of the arm) closed, creating a stiff, 3D structure with no need for heavy locking mechanisms.

First author Stefano Mintchev holds the quadrotor (Photo: LIS, EPFL, Alain Herzog).

The folding quadrotor currently doesn’t have an automatic “putting away” mode, meaning that the arms must be manually returned to the wrapped configuration. However, at the deployment stage, where speed is of the essence when trying to locate vulnerable people, this mechanism may just be a lifesaver.

Reference

S. Mintchev, L. Daler, G. L’Eplattenier, L. Saint-Raymond & D. Floreano, “Foldable and Self-Deployable Pocket Sized Quadrotor,” In 2015 IEEE International conference on Robotics and Automation (ICRA 2015), Seattle, Washington, USA, May 26-30, 2015.  A pdf of the full article can be downloaded from infoscience.

Photo: Courtesy Audi.

Last month, Swiss startup noonee completed the first round of testing for their Chairless Chair with German car manufacturer Audi. The Chairless Chair is a wearable sitting exoskeleton for people working on construction lines that is designed to allow movement while still providing enough support to prevent the repetitive stress and health problems that are so common in this kind of work. 

Rather than just providing a chair to sit in, noonee avoids the issue of muscle wastage by designing the exoskeleton to support the wearer in such a way that they continue to use their muscles.

The version of the Chairless Chair tested at Audi is called TITAN, which made out of titanium. The next stage of development will be to create a version manufactured from carbon.

noonee CEO Keith Gunura said, “With the user feedback we collected we are now stepping up development of the Chairless Chair to bring it to an amazing product that provides the support needed while working. Our target is that early Q1 2016 there will be a ready product to push forward the ‘Chair-olution’ to the rest of the world!” noonee is a spin-off from the Swiss NCCR Robotics.

Dr. Mathias Keil, Head of Industrial Engineering Methods at AUDI AG added “With the use of the chairless chair, we are continuously improving ergonomics in assembly operations. We also anticipate new applications for colleagues with reduced physical capabilities.”

Interested companies can register their interest by sending an email.

• Noonee: The chairless Chair
• Novel robots for gait and arm rehabilitation: Interview with Robert Riener
• Unpowered exoskeleton improves efficiency of human walking
• 3 exoskeleton companies go public

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

The testbed allows the quadrocopter’s high speed flight behavior to be characterized in order to determine drag characteristics, propeller efficiency, and the physical limits of the machine. It is also being used to safely develop high-speed maneuvers such as emergency braking.

Note that it is possible to remove the central pole by balancing the forces acting on the strings; this could be then used in performance settings, possibly enhanced by light and sound effects.

This research was conducted at the Flying Machine Arena at ETH Zurich.

Reference:

Maximilian Schulz, Federico Augugliaro, Robin Ritz, Raffaello D’Andrea , “High-speed, Steady Flight with a Quadrocopter in a Confined Environment Using a Tether “, IROS 2015, submitted.

If you liked this article, you may also be interested in:

• Three new quadrotor videos demonstrate agile control and the power of machine learning
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• Video: Watch flying robots cooperate, throw and catch balls
• Quadrocopter failsafe algorithm: Recovery after propeller loss

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

The Kuka lightweight robot with a mounted stone tool replica in an ETH Zurich lab. (Photo: Fabio Bergamin / ETH Zürich)

By Samuel Schlaefli

With the help of robots, archaeologists may soon be able to compare their findings with data from thousands of experimental reference samples, enabling them to determine tool use in the Stone Age. ETH scientists have developed a robotic system and presented it at the industry fair in Hanover.

Kuka-Roboter

Radu Iovita is an archaeologist. He remembers well his student days, when he spent hours scraping away at animal skins with replicas of stone tools found at archaeological sites – all for a bit of pocket money. Through analysis of wear traces under a microscope, archaeologists seek to determine how the tools were used thousands of years ago. This method, known as ‘use-wear analysis’, is a standard approach in modern experimental archaeology today.

“Manual use-wear analysis is incredibly time consuming, and we are unable to control factors such as the force with which a tool is used or its position,” says Iovita. He has spent the past few years looking for opportunities to conduct controlled experiments and experienced initial success with a system using air guns to run a controlled test on the impact-related fractures of Stone Age spearheads.

Archaeologists and robotics team up

But the archaeologist was looking for ways to examine all tools and their application systematically – as well as being as automated as possible. Iovita, now a researcher at the Monrepos Research Centre (RGZM-Leibniz Research Institute for Archaeology) in Neuwied, Germany, remembered Jonas Buchli, a professor at the Institute for Robotics and Intelligent Systems at ETH Zurich, whom he had met 10 years before at a summer school on complex systems. The ETH professor was impressed from the outset with Iovita’s idea to automate archaeological research through the use of robots to standardise the measurements.

Buchli’s then graduate student Johannes Pfleging equipped replicas of stone tools with sensors. Just as Iovita did during his studies, Pfleging scraped at the animal skins, but with a difference: his movements and the force used were recorded by a computer. In doing so, he found evidence that the sensors provided important data that could be used to reproduce and compare the experiments at a later date. But use-wear analysis still remained time-consuming.

By a stroke of luck, the Kuka robotics company had just announced an Innovation Award that made lightweight robots with force control available for use in innovative research projects. These robots are very light in comparison to their load weight and can adapt the forces used to the determined resistance within milliseconds.

A robotic arm for fully automated analysis

One such Kuka robot has been in Buchli’s laboratory since last December. Pfleging, now a doctoral student, has fixed the grey robotic arm with its seven degrees of freedom on to a wooden table. At the end of the arm is a plastic adapter with a piece of wood in which he glued a replica of a stone tool. As soon as Pfleging starts a computer program he wrote himself, the arm begins to use the stone to scrape a piece of leather fastened to the table. After a few rounds, it bends down and guides the tool under a microscope next to it on the table. An image of the stone, magnified 80 times, appears on Pfleging’s computer, revealing fine abrasions.

“With such a system, we can not only automate the painstaking production of wear traces, but also the analysis of the replica,” explains Buchli. Several robots could work leather, stone or wood with replicas of tools 24 hours a day and run the tool after every 50th movement under the microscope to take images of the surface. Thus, a combination of the data and force of the robotic arm would allow a precise reconstruction of how certain abrasions had been achieved. “Through such analytical data, we could one day create massive databases with all the characteristics of archaeologically relevant information on materials and their wear patterns,” explains Buchli.

Deeper insight into ancient civilisations

Wider comparisons such as these have the potential to accelerate the production of knowledge in archaeology and paleoanthropology. For each archaeologically-recovered stone artifact, the researchers could compare a microscopic image with thousands of records from use-wear experiments from around the world, allowing them to make inferences about how the tool was formerly used.

“In archaeology until now, we have been primarily occupied with the morphology of objects,” says Iovita. “However, it is only when we know what the tools were used for that we can make inferences about culture.” It is also generally assumed today that the prehistoric evolutionary development of humankind can be inferred from how tools were used and the cognitive skills needed to use them. In particular, scientists are still groping in the dark when it comes to the use of tools from the period between 3 million and 50,000 years before present.

Paradigm shift underway

Currently, Iovita is experiencing some opposition from within his own profession. Some believe that manual experiments are closer to the past reality; others find that use-wear analysis in general does not advance archaeological theory. Iovita thinks this is mainly due to the fact that most archaeologists have a humanities background and are not familiar with the world of engineers.

“However, a generational and paradigm shift is currently underway,” he believes. “The interest in automated analysis is growing and more and more archaeologists have access to the relevant technology.”

Iovita has put in an application for the establishment of a trace laboratory at the research centre in Neuwied, where the first use-wear analysis with robots will be conducted in the next two to three years. Buchli and Pfleging have now presented their robotic system to experts as part of the Kuka Innovation Award at the industry fair in Hanover. Next, they will develop a prototype in their laboratory that is better suited to archaeological use and cheaper than conventional lightweight robots with force control.

“In 10 years’ time, robotic analysis will be the standard in archaeology,” predicts Buchli. “For the first time, research results would be truly comparable because the methodology behind it is standardised and the devices properly calibrated.”

This article first appeared on ETHZ News. 

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Photo credit: Robotics & Perception Group, University of Zurich.

When a drone flies close to a building, it can temporarily lose its GPS signal and position information, possibly leading to a crash. To ensure safety, a fall-back system is needed to help the quadrotor regain stable flight as soon as possible. We developed a new technology that allows a quadrotor to automatically recover and stabilize from any initial condition without relying on external infrastructure like GPS. The technology allows the quadrotor system to be used safely both indoors and out, to recover stable flight after a GPS loss or system failure. And because the recovery is so quick, it even works to recover flight after an aggressive throw, allowing you to launch a quadrotor simply by tossing it in the air like a baseball.

How it works

Photo credit: Robotics & Perception Group, University of Zurich.

Our quadrotor is equipped with a single camera, an inertial measurement unit, and a distance sensor (Teraranger One). The stabilization system of the quadrotor emulates the visual system and the sense of balance within humans. As soon as a toss or a failure situation is detected, our computer-vision software analyses the images for distinctive landmarks in the environment, and uses these to restore balance.

All the image processing and control runs on a smartphone processor on board the drone. The onboard sensing and computation renders the drone safe and able to fly unaided. This allows the drone to fulfil its mission without any communication or interaction with the operator.

The recovery procedure consists of multiple stages. First, the quadrotor stabilizes its attitude and altitude, and then it re-initializes its visual state-estimation pipeline before stabilizing fully autonomously. To experimentally demonstrate the performance of our system, in the video we aggressively throw the quadrotor in the air by hand and have it recover and stabilize all by itself. We chose this example as it simulates conditions similar to failure recovery during aggressive flight. Our system was able to recover successfully in several hundred throws in both indoor and outdoor environments.

More info: Robotics and Perception Group, University of Zurich.

References

• Quadrocopter failsafe algorithm: Recovery after propeller loss
• Video: Throwing and catching an inverted pendulum – with quadrocopters
• Developing trust in autonomous robots: Seminar with Michael Wagner
• From sideshow to main event, drones are making their mark in entertainment

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Matthias Kohler, Balz Halter and Jonas Buchli (Photo: Nicole Bachmann).

By Felix Würsten and Corinne Hodel (Interview).

Digital technologies have already turned many areas of the economy inside out. In this interview with Swiss NCCR Digital Fabrication researchers Matthias Kohler, Balz Halter and Jonas Buchli, we hear how construction is the next sector set to undergo a change, enabling more efficient processes, new materials and more varied houses.

The website of the new National Centre of Competence in Research (NCCR) Digital Fabrication states that: “Digital fabrication promises to revolutionise architecture.” Does architecture need a revolution?

Matthias Kohler: That is less of an objective than an observation: the construction process is still highly conventional. Other sectors of the economy have been profoundly transformed by digital technologies. This raises the question of whether architecture and its downstream construction processes are also set for a change. The NCCR Digital Fabrication addresses this question: what is the added value if components are fully assembled by machines? What conditions need to be fulfilled so that people can work together with robots on building sites? And what effect will this have on drafting, planning and the construction culture?

Yet it must be noted that houses were built by robots in Japan some time ago. Are you reinventing the wheel?

Kohler: It’s true that some initial steps towards automation on building sites were already taken in Japan in the 1990s. There was a boom, but it collapsed suddenly for economic reasons. The idea at the time was to bring serial mass production from factories to building sites. It worked, but this technocratic approach resulted in limits on the architecture and bland buildings. In today’s construction culture, a fitting, “tailor-made” solution for each situation is the objective. The quality of our living environments relies on this. When we take our robots to the building site today, our motivation is quite a different one: we are trying to establish how the processes can be rationalised, but continue to allow tailor-made production at the same time. That’s the actual novelty: every machine-made component can look different, even the individual production steps can be customised to a certain degree. That’s what we’re doing with our robots, for instance: depending on the task, the same robot uses different tools to assemble, process or shape something. This approach results in rational production already for relatively small lot sizes.

Is there actually any demand from developers for individualisation?

Balz Halter: Developers certainly want a more individualised appearance for their buildings. This is also having an impact on architecture: new shapes and materials are being sought. In the construction industry, we abandoned the mass production mentioned earlier because we noticed that this approach keeps resulting in the same buildings. The construction industry is indeed aiming for individualisation, because ultimately it also offers a way to stand out amongst competitors.

What is your motivation as a robotics expert to look at construction processes?

Jonas Buchli: Many sectors of the economy have been turned inside out by digitalisation. This has affected, above all, areas where either data play a key role or where problems can be easily structured. In robotics, however, we now need to take the next step, which is to say that these technologies need to be brought to areas that are less structured, where more flexibility is needed and the machines need to react in a more timely fashion. The construction industry is an interesting starting point for this. A building site is certainly less well-structured than a factory, but still not quite as open as the world of service robots, for instance, which perform activities independently in the household. The potential in the construction industry is huge. But we will only be able to tap it if we solve complex robotics problems. That’s an interesting challenge for me as a researcher.

What has it been like to work with architects?

Buchli: When working with architects, the challenges and possibilities are entirely different than when “only” collaborating with engineers. I am learning an awful lot and am facing an entirely new perspective. What has surprised me is how pragmatic their approach is to using technologies and how target-driven their work is.

What has been implemented to date?

Kohler: We’re currently still at an early stage of research, although some companies have already taken specific steps towards digital fabrication. It will take a great deal of time until the new production processes have become ingrained and until the experiences have been integrated along the entire production chain. In tile and timber construction, we have seen that implementation will take at least six to ten years. When applied across the entire construction industry, these changes will take several decades. What excites me is the question of what we will gain from these technologies in terms of quality in architecture and in the construction processes, and what benefits they will bring for Switzerland.

Halter: In practice, digital fabrication is certainly a known concept today. In timber construction, in particular, a lot is already being done. The fact that these technologies are not yet broadly applied is not so much a matter of possibilities: the problem is that we can only produce digitally if the data are available in a corresponding form. In this area, our industry is simply underdeveloped. There is no integral process from drafting to production through to operation. If we were to start by handling the data correctly during the planning process, implementation would be far easier. We actually have all tools at our disposal already. But our industry is still not able to use these tools.

Why is that?

Halter: First, this has to do with the fact that we still think in a very subsection-specific way. In other words, we don’t understand the building as an overall system. Second, we keep interrupting the planning process because we transfer data from one place to another. And third, the construction industry is organised in a highly commercial and work-sharing manner. The production of a car is a unified procedure; that’s not the case for buildings. But construction is not more complex than car manufacture – we are simply aligned in such a way that it becomes more complicated. That’s why processes are still very antiquated on building sites. But that is also an opportunity, of course, in particular for the design process. What’s important to us is that digital fabrication results in quality improvements and ultimately also generates commercial benefits.

Buchli: The entire development will likely happen in a similar way as in computer technology. When we had the first computers on our desks, processes were hardly productive yet. But there were early adopters, who were thinking ahead. Only now, after many years, are computers really productive for normal users. We will undergo the same development in the construction industry. However, the problem is far more complex here, which is why the time frames will be longer. We won’t be looking back in two or three years saying whether it has worked or not.

Where do you expect to see the first steps?

Buchli: What will likely become established in the near future are transport applications as well as certain precision applications. Today, we can produce structures at a level of precision that a human cannot achieve, at least not within the same period of time and working under the same conditions that robots do. However, if we want to bring these things to building sites, we need to increasingly include information from the building in the planning process. This was a directed process in the past: first plan, then execute. What we need now is to close the circle.

Kohler: The crucial question is, of course, how this vision is implemented. Up to this point, architecture has mainly focused on the mental work. The idea was to develop a sophisticated planning software that integrates everything. This still largely works in planning today. However, where the matter becomes physical, the processes mostly remain conventional. We are now changing our perspective and looking for solutions that can be integrated retroactively, in other words from execution to drafting. I’m convinced that this approach will make it far easier for the construction industry to initiate a sustainable transformation from within.

Do you share this view?

Halter: A lot speaks for this approach. The development is driven strongly by architects who focus on the end product and who work with components and materials that can only be implemented in a digital process. For instance, there are facades that can only be planned and produced on a data-driven basis. It will also be exciting to see what influence 3D printers will have. This is precisely the point: we look at what options we have in production and go back to the draft with this as our vantage point until both ends meet.

Kohler: 3D printing is a very interesting catchword: 3D printers cannot simply be applied to architecture, although it is often presented this way. In principle, additive processes are interesting for us, of course. This has to do with the fact that good architecture is based on the artistic assembling of elements to create rooms that are larger than the machines that build them. This is where 3D printing comes in: how do we find the structuring strategies in architecture that are based on digital technologies, but nevertheless take into account the requirements and economy of architecture? For instance, it makes little sense to print an entire building. Due to the resolution at which the printer works, the construction process takes a very long time and the material is also very expensive. However, if larger construction elements are used, a construction-aligned resolution can be achieved.

Can you elaborate a little on this?

Kohler: I am speaking about new digital material systems, for instance: suddenly it’s possible to handle a building material in an entirely different way thanks to digital technologies. It is very possible that this will result in developmental leaps. We also need to consider the ecological aspects: today, concrete walls are designed in such a way that they withstand the worst load scenario. These walls are built with a straight mould system. This results in about one third of the concrete not actually being needed from a statics perspective. If we use systems that don’t need moulding, there are direct consequences for our handling of material resources. If the construction culture develops in this direction, we will thereby also be able to create added value in this area with the use of digital fabrication. Our research projects allow us to generate knowledge which Swiss companies will be able to use internationally. We would be delighted if the industry were to pick up on these stimuli and if our projects were to result in interesting collaborations.

What effects do these developments have for the people involved in the actual construction process?

Halter: It’s becoming increasing difficult to find the experts required. For that reason, we need to try to support the processes on building sites in terms of information technology in such a way that the required skills are more limited. This objective is also driven by commercial considerations, because the individual worker is becoming increasingly expensive.

What do you think of the roll-out of the new MAS Digital Fabrication programme at ETH Zurich, which is starting for the first time this year?

Halter: No question: we need a programme like this. Because the development we have just been discussing can only happen if we also make changes to education. We need people who can handle these types of technologies. We are consistently initiating innovations, but are also noticing that people are out of their depth in practice, because they are faced with something that they don’t know. A planner doesn’t see why he should do something differently, because he doesn’t get paid more but he does have to take on more risk. If he has no inherent drive to try a different approach for a change, and cannot even know the opportunities, then he simply won’t do it. That’s understandable.

Matthias Kohler is Professor for Architecture and Digital Fabrication at the Architecture Department of ETH Zurich. In 2005 he established the world‘s first robot laboratory for nonstandardised fabrication processes in architecture with Fabio Gramazio and thereby opened up an entirely new field of research.

Jonas Buchli is Professor for Agile Robotics at ETH Zurich. His research focuses on modelbased approaches to controlling robotic locomotion and understanding human locomotion as well as on machine learning and on dynamic service and field robots.

Balz Halter is the owner and chairman of the board of directors of Halter Unternehmungen, which are active in the development, construction and operation of real estate property. He is an ETH graduate civil engineer and lawyer.

If you liked this article, you may also be interested in:

• New Master of Advanced Studies (MAS) in architecture and digital fabrication at ETHZ
• Swiss to invest almost CHF30 million in digital fabrication research over next 4 years
• Robots Podcast: Future citieS, with Matthias Kohler
• Robots Podcast: Termite-Inspired Construction

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Photo credit: Gramazio Kohler Research, ETH Zurich.

In September a new Master of Advanced Studies (MAS) ETH in Architecture and Digital Fabrication will be offered by the Gramazio Kohler Research chair at ETH Zurich. This one-year, full-time program focuses on digital design and full-scale fabrication using state-of-the-art robotic fabrication facilities at ETH. The MAS is embedded within the National Centre of Competence in Research (NCCR) Digital Fabrication, itself an ambitious research initiative at the intersection of architecture, engineering, robotics, material and computer sciences. Interested candidates are invited to apply until April 30, 2015.

The term “digital fabrication” refers to the seamless combination of digital planning with the physical fabrication process. The project data is sent to a machine, and directly implemented in reality. However, this exchange of information could also work in the other direction: the physical conditions could immediately influence the computer-aided designs.

For architecture, this opens up possibilities that were previously undreamt of, and which go far beyond purely design-related aspects. New construction systems, material systems, resource-saving production, efficient-yet-flexible engineering and construction processes, and a transition from mass production to customised industrial production all promise a decisive developmental step towards a sustainable building culture for the future.

Unlike objects produced by conventional computer-controlled production, architectural objects are typically larger than the actual production facility, they are always unique, and they are usually produced on site. As a result, research on this topic is confronted with completely new questions: How can the automated industrial robot in the factory hall become a reactive robot for the building site? What intelligent material systems and construction systems are suited to a robot-based additive (and thus waste-free) building technique? And what do the new planning and building processes mean for the future interaction between humans and machines?

The practicability (and thus the success) of digital construction will depend not only on research, but also, to a great extent, on experts who can ensure the transfer of knowledge into practice. This is why the NCCR Digital Fabrication, in conjunction with ETH Zurich, is launching the new Master of Advanced Studies (MAS) in Architecture and Digital Fabrication next autumn. As the education platform of the NCCR, this programme is embedded in the context of the latest research findings. In the NCCR’s unique robotic fabrication facilities, the students will also have the opportunity to research digital design and construction processes, and to implement these directly in large-scale prototypes.

More info: http://www.dfab.ch/education/mas/

If you liked this article, you may also be interested in:

• Swiss to invest almost CHF30 million in digital fabrication research over next 4 years
• Robots Podcast: Future cities
• Three new quadrotor videos demonstrate agile control and the power of machine learning

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Sensory-Motor Tissues for Soft Robots

In this video, PhD student at LIS, EPFL and NCCR Robotics Jun Shintake explains his project “Sensory-Motor tissues for Soft Robots”.

For more information on this project please see:

The project’s website

New soft antagonistic actuator enables robots to fold

A foldable antagonistic actuator (academic paper)

Variable stiffness material based on rigid low-melting-point-alloy microstructures embedded in soft poly(dimethylsiloxane) (PDMS) (academic paper)

Ground-Air collaboration between robots (Photo: RPG and Alain Herzog).

Working in the field of rescue robotics, the Robotics Perception Group (UZH and NCCR Robotics) works on how to get air robots communicating with ground robots, with the aim of exploiting the strengths of each by working in a team.  In the video below, student Elias Müggler explains how he is doing this.

For further information:

Robotics Perception Group website

Aerial-guided Navigation of a Ground Robot among Movable Obstacles (paper by Elias Müggler)

Autonomous flying robots – Davide Scaramuzza at TedxZurich:

Demonstration of the project, winning the Kuka innovation award 2014:

The Pleurobot (Photo: Hillary Sanctuary & BioRob).

The Pleurobot is a bioinspired robot being developed by the BioRob at EPFL and NCCR Robotics. Taking it’s cues from the salamander, the Pleurobot is a walking robot that can change its gait to help it to navigate uneven terrain, and is currently learning to swim.  Watch the video to see the researchers discuss what they are doing with the Pleurobot and how they hope to improve it in future.

For further information on the Pleurobot please see:

The project’s homepage

Introducing Pleurobot (video)

Flyability, a spin off company from LIS, EPFL and NCCR Robotics, has won the $1M inaugural UAE Drones for Good competition with Gimball, the world’s first crash resilient drone.

The award was initiated by Sheikh Mohammed Bin Rashid Al Maktoum, Vice-President and Prime Minister of the UAE and Ruler of Dubai with the aim of “transforming these exciting technologies into practical solutions for improving people’s lives today”.  Referred to by some as “the World Cup of Drones”, the competition involved the 39 semi finalists showcasing their technology in front of a panel of international judges. Flyability impressed observers with its ability to fly in disaster tight and cluttered disaster zones, outside a pilot’s direct line of sight. Also noted was the Gimball’s unique design, which actively invites collisions rather than trying to avoid them. Its rotating gimbal system and protective wire cage not only keep the drone safe from crashes, but also protect humans working in close proximity to the device. The team was awarded $1M USD in prize money.

Flyability SA is one year old and its founders, Adrien Briod and Patrick Thévoz, are working to bring the Gimball to market. Their first aim is to use it for industrial inspection and to locate victims after natural disasters, but they plan to tackle the security and entertainment markets at some point too.

If you liked this article, you may also be interested in:

• UAE launches “Robotics for Good” competition on the heals of Drones for Good success
• Drones For Good Award announces semi-finalists
• Minesweepers 2014: Outdoor robotic competition on humanitarian demining
• Aerial drone maps show Philippine typhoon devastation, aid in reconstruction
• The latest in ultra-affordable robots: AFRON competition announces winners
• Fukushima photo essay: A drone’s eye view

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Knee orthosis as worn by first author Mike Tucker (photo: ReLab, ETHZ and Alain Herzog).

Much has been made of the numerous advances in robotic prosthetics and orthotics (P/O) over recent years, and the question of how to control these devices so that they work in accordance with the intention of the user is a continuing dilemma for roboticists. 

A team from four labs within NCCR Robotics, across ETH Zurich and EPFL (ReLab, ETH Zurich; LSRO, EPFL; SMS, ETH Zurich and CNBI, EPFL) have recently published a joint paper in the Journal of NeuroEngineering and Rehabilitation, in which 10 experts from the field review the state of the art in control approaches for active lower limb P/Os. They argue that for P/Os to be fully viable and to advance further, they must be treated as part of a framework whereby the control system becomes integrated with the user’s sensorimotor system.

Traditionally, the fields of orthotics and prosthetics have been viewed separately, with hardware and controllers developed with a specific portion of the body in mind (i.e. knee, ankle and hips). By taking a broad survey that includes research for all joints of the lower limbs across the different fields (rather than just looking at a small subset), it is hoped that future developments can blur the lines between fields and create technologies that can ultimately restore walking to those with physical or neurological impairments.

This open access review pieces together where the state of the art is now and what work still needs to be done, providing valuable background about the field.

The authors behind the paper have been working to enhance communication between research groups, and to promote a more holistic approach to P/O devices. One of the co-authors is organizing next year’s Cybathlon, where teams comprised of bionic technology developers and a pilot will compete in one of six races.The competition’s ultimate aim is to increase discussion between academia, industry and end users through friendly competition.

Raffaello D’Andrea’s robots can do amazing things: play soccer and ping-pong, perform complex choreographed acrobatics in the air, build towers brick by brick, and move pallets around warehouses. (See the video at his Web site, and check out his TED Talk.)

He also cofounded Kiva Systems, which was acquired by Amazon.com in May 2012 for $775 million with the hope of using the company’s orange robots to move items around warehouses, get products to consumers faster, and lower costs. Robots have reportedly been deployed in Amazon warehouses around the country.

Massimo Russo, a senior partner and managing director in the Boston office of The Boston Consulting Group and the regional leader of the Technology Advantage practice in North America, recently spoke with D’Andrea about the future of robotics. 

Edited excerpts from their conversation follow.

You’ve developed some amazing robots that play soccer and ping-pong. What novel potential uses for business and society do you see for robots in the future, and where are we liable to see robots next?

In the short term, the biggest impact is going to be from how we make things—how we extract things from the ground (mining, agriculture), how we make things (manufacturing), and how we distribute them. We’re going to see a lot of that innovation find its way into these sorts of realms in the next three to five years.

I still think we’re a ways away from the general-purpose robot in your home that’s going to do your bed, do the dishes, and so on. But I think we will also see in the medium-to-long term an infiltration of automation and robotics in the home.

A lot of your research has been around learning systems and learning robots. Do you see applications of learning algorithms for products such as the driverless car?

One of the biggest advantages of learning and adaptation is that it allows you to create powerful systems that are inexpensive to make. If you try to make a very precise robot, it costs a lot of money. If, however, you relax that requirement to make a machine that right off the bat is high performance, and let it learn and adapt tobecome high performance, it becomes economically viable to deploy such a machine. I think learning and adaptation will have a huge impact on how we make machines.

What has changed over the past few decades, either in terms of the underlying technology or in the economics of robotics, and how do you see robotics changing going forward?

A lot of it is probably best thought of as reaching tipping points. Let’s say you make a robot that could do something and that it costs $1.25 for it to do that, and a person could do the same thing for $1. You’re not going to use that robot. But next year, let’s say it takes 5 cents less to do it, so it becomes $1.20, and then $1.15, and then $1.10. From an outside perspective, you may say there’s no progress being made in this technology. Yet when that tipping point comes, when this robot can do the job for $1 or less, all of a sudden it becomes economically viable and everybody jumps in to adopt it. I think that there has been steady progress in the development of robotics and automation, but I think we’ve just reached various tipping points that will make them, all of a sudden, economically viable to deploy.

What kinds of systems innovations are you seeing? And if you think about this from a company perspective, are there interesting startups or maybe lessons even for the more established robotics players?

One of the neat things that big companies are doing is using robots in a cooperative fashion. A lot of people think that’s been going on for a long time, but actually that’s not true. For example, having multiple robot arms work together to manipulate objects for manufacturing, for installations, and so on—that’s a pretty new development. A lot of the big robotics companies are exploring these ideas—also integrating different types of automation technologies together. I think that’s an exciting development that big companies are mainly undertaking.

With startups, what really gets me excited are the folks who are looking at new ways to think about location and navigation. If we really want robots or autonomous systems to be pervasive, they need to know where they are—not just outdoors but also indoors. A lot of startups are trying to solve this problem by using advances in computer vision—and advances in inexpensive sensors, accelerometers, gyros, magnetometers, you name it—and in the algorithms to fuse all that information together and provide a local awareness for autonomous systems that just doesn’t exist right now.

Your startup, Kiva, was acquired by Amazon. What’s the long-term potential you see for warehouse logistics and management, distribution, and operations going forward?

What’s interesting about Kiva was that in the original business model, the key value that we thought Kiva was bringing to the space was cost. We thought, “Here’s a system that will allow us to reduce the cost of filling orders.” But it turns out that it was many of our secondary value-adds that were really exciting to customers: flexibility, adaptability, and a reduction in human errors. There was the fact that you could set up a warehouse in six weeks instead of two years, and the fact that if you wanted to reconfigure the warehouse, it was easy to do—which you couldn’t do with existing automation. The lesson was that businesses really want flexibility and adaptability.

Do you see applications of Kiva’s technology outside of warehouses, perhaps in more of a manufacturing environment?

Absolutely. We always thought about manufacturing when we were growing the company, but we were really focused on distribution. There was just so much opportunity in distribution that we said, well, manufacturing will come later—maybe we will spin off another company, maybe we will start another division. That still may happen. The underlying ideas can certainly be brought to manufacturing.

There’s been a lot of discussion about big data and companies hiring decision scientists. Are the underlying skill sets very similar, or should companies be thinking about hiring control engineers as well?

The right answer is somewhere in between. You can try to model absolutely everything and never look at data, and try to predict. This is what the Greek philosophers used to do—sit around and try to think of how the world works and forget about observations: “There should be a way to think things through.” That’s one extreme. The other extreme is, “Forget about trying to have any understanding of the physical world, we’re just going to look at data, and the data is going to tell us what causal relationship should take place and how the world works.”

We like to do things in between. We like to have physical models. We like to sit on the shoulders of the giants who have developed all of this understanding about how the world works. But we also like to use real physical data to augment our models, to refine our models, to tell us where our models have deficiencies. The more data you have, the better you can do that. I think there’s a lot to be gained by combining those two approaches. Folks who are only focused on big data—I think that’s limiting. Folks who can only do modeling—I think that’s limiting. You need people who can do modeling and who can work with big data.

Systems are inherently unpredictable and complex when you start connecting them. Do you have any cautionary tales for business leaders about how behaviors could be unpredictable around business systems?

There are many examples of when feedback or interactions with the environments can cause things to go wrong. One example that comes to mind is the Tacoma Narrows Bridge. When this bridge was designed, people didn’t really take into account the interaction of the bridge with a constant flow across the bridge. That caused the bridge to become unstable, and it collapsed. There was Chernobyl, which was basically a system that ran wild and became unstable because of various feedbacks that caused a positive runaway cycle.

Feedback is very powerful, but it’s also very dangerous. You have to be very careful when you start feeding things back without some sort of supervision, because you get unpredictability. It’s a two-edged sword: you want to harness the power, but at the same time you don’t want things to go wrong.

How do you get around that? One, try to understand things before you connect them together and try to predict what could go wrong. You can do that by simply trying to understand the system and trying to reason through it, but also you can make simulation models, agent-based models, you name it. I think that’s the first point. Second, just be cautious. Try things out, and see how it works. For really complicated things, it’s very difficult to prove that something is going to work when interconnected. A lot of times you just have to try it out.

The DALER is a winged robot that can also walk.

The issue of how to use one robot across multiple terrains is an ongoing question in robotics research. In a paper published in Bioinspiration and Biomimetics today, a team from LIS, EPFL and NCCR Robotics propose a new kind of flying robot that can also walk. Called the DALER (Deployable Air-Land Exploration Robot), the robot uses adaptive morphology inspired by the common vampire bat, Desmodus rotundus, meaning that the wings have been actuated using a foldable skeleton mechanism covered with a soft fabric so that they can be used both as wings and as legs (whegs).

The DALER is being designed to be used in search and rescue operations, and its dual modes of locomotion will enable it to fly long distances to survey large spaces in a short timespan, and then to walk into dangerous or inaccessible areas.

One of the main problems in trying to get a flying robot to walk in small spaces is the surface areas of the wings. The wings of a flying robot must be wide in order to maintain flight, but this makes it difficult for them to fit into smaller spaces. After observing D. rotundus, the research team used a foldable actuator that allows the wings to fold into a smaller space, and to rotate around a hinge that attaches the whegs to the body in order to enable walking. D. rotundus doesn’t look very pretty when it walks, but it has certainly perfected the art of using all four limbs for two purposes.

The DALER using its wings to walk. Wingerons at the end of the wings rotate to facilitate walking.

To design the robot, the team had to first designate the primary mode of locomotion – in this case flight, as the DALER will cover the longest distances this way. The wings were then adapted for walking, taking into consideration the need to not add extra weight when the DALER is in flight mode. The resulting wing is equipped with wingerons, with an axis of rotation close to their centre of aerodynamic pressure and physical centre, so as to satisfy the constraints of both ground locomotion and flight. The best shape found for these wingerons is a triangular one.

The addition of wingerons poses a problem regarding the use of actuators. Flight maneuverability requires rapid wingeron movements and low torque, whereas walking requires the opposite conditions. To cope with this problem, the DALER uses a terrestrial actuator configuration, but with an optimized wingeron size, to force the working point of flight control inside the operating range of the terrestrial actuator, while not compromising flight maneuverability.

A second issue in creating a fixed wing drone capable of walking on the ground is with the morphology, thanks to the different centre of mass requirements for the two modes of locomotion. For this reason the DALER is equipped with foldable wings, so, much like the bat that inspired it, the DALER can walk on its haunches. These adaptations mean that the DALER can reach 20m/s in the air and 6cm/s on the ground, with a maximum step distance of 6cm.

Researchers hope that in the future the DALER might be used to find victims in dangerous areas after a natural disaster, for example. They envision the DALER being remotely deployed to fly to an affected area, and then walking through a disaster zone (e.g. a damaged building) to locate victims so that human rescue teams can concentrate their efforts where they are needed, rather than using time to search for victims in a dangerous environment. Future development of the DALER will include the ability to hover and to take off autonomously from the ground – necessary features if the robot is to return safely to its home base after a mission.

If you liked this article, you may also be interested in:

• Multi-purpose wings allow flying robot to walk across rough terrain
• Robots Podcast: Origami robots
• Robot bodies and how to evolve them
• ShanghAI Lectures: Josh Bongard “Morphological Change in Machines Accelerates the Evolution of Robust Behavior”
• Robots Podcast: Bio-inspired locomotion

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The e-dura is able to function while being bent (photo: © EPFL 2015)

A team from EPFL and NCCR Robotics lead by Profs Stéphanie Lacour, Grégoire Courtine and Silvestro Micera published an article in Science today describing their e-dura implant that could revolutionise how we think about and treat paralysis. Until now, implants placed beneath the dura mater of the spinal cord have caused significant tissue damage when used over long periods. Research shows that the new e-dura implant is viable for months at a time in animal subjects. The team is now moving on to clinical trials in human subjects and is developing their prototype to take to market.

Previous work by the team have enabled animals paralysed by spinal cord injury (SCI) to voluntarily walk again using both chemical and electrical stimulation. While this was a huge advancement in both engineering and biomedicine, there are a number of issues with moving this highly successful laboratory experiment to every day human life, as previous iterations used wire electrodes which were limited to two sites and were difficult to place accurately on the spinal cord. Drug delivery was via an intraperitoneal injection, i.e. an injection into the body cavity. While the results were outstanding, more work needed to be done before this solution could be taken out of a lab situation and into a real world one.

The cracked gold conducting tracks carry impulses, while the fluidic channel provides chemical stimulation (Photo: © EPFL 2015).

What is presented in the Science paper is a soft and stretchable implant which can be directly placed beneath the dura mater, the nervous system’s protective casing, and onto the spinal cord for months at a time, a length of time which would result in significant tissue damage with all previous surface implants. The e-dura is also designed to carry electrical impulses and chemicals. Under experimental conditions, walking was restored in paralysed rats after implanting followed by two weeks of training using a robotic postural interface also developed as part of NCCR Robotics.

The 200nm thick implant is predominantly made of silicone covered with 35nm thick microcracked gold conducting tracks which can stretch and rebound without damage. The electrodes contained within the implant are made of a unique mix of silicone and platinum microbeads, allowing the implant to function and conduct electricity when moved in any orientation, this combination of the flexible electrodes and conducting tracks mean that electrical impulses can be delivered to the spinal cord. A complimentary fluidic microchannel (100μm x 50μm in cross section) delivers neurotransmitters to reactivate the nerves within the spinal cord. E-dura is implanted over the lumbosacral segments below the site of injury and engages with the “dormant” lumbar locomotor circuits.

The unique implant is able to sit directly on the spinal cord or brain.

The effectiveness of the e-dura is down to its mechanical properties which allow it to be soft and elastic, thus ensuring that it does not rub against the spinal cord causing the issues seen in alternative implants. To create an implant to be so soft and flexible but that is also capable of electrical stimulation and local drug delivery, and this over several weeks in vivo was no small task and involved a team comprising experts in materials science, electronics, neuroscience, medicine and algorithm programming.

Co-author Prof. Grégoire Courtine says of the implant that it’s “ the first neuronal surface implant designed from the start for long-term application ”, and, although it’s only been tested in animals so far, the long term applications and potential implications for the disabled community are clear. As the dura mater also surrounds the brain, it is not just SCI patients who could benefit, but also potentially those with neurological diseases, such as Parkinson’s. The team is now moving on to clinical trials in human subjects and are developing their prototype to take to market.

The Swiss National Center of Competence in Robotics (NCCR Robotics) is a federally funded programme bringing together robotics laboratories from EPFL, ETH Zurich, University of Zurich and University of Lugano to work on wearable, rescue and educational robots.

A full transcript of the paper will be published in print on 09.01.2015 and is available online at sciencemag.org: Minev, I.R., Musienko, P., Hirsch, A., Barraud, Q., Wenger, N., Moraud, E.M., Gandar, J., Campogrosso, M., Milekovic, T., Asboth, L., Torres, R.F., Vachicouras, N., Liu, Q., Pavlova, N., Duis, S., Larmagnac, A., Vörös, J., Micera, S., Suo, Z., Courtine, G. and Lacour, S., “Electric dura mater for long-term multimodal neural interfaces,” Science, Vol. 347 (6218), pp. 159-163, 2015.

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Working out the mechanics of walking is a major step towards creating assistive technologies.

When thinking about robots that can be used to care for the elderly, most people imagine humanoid robots that are meant to help with cooking, cleaning and socializing. But what if robots could be used to keep elderly people from needing help in the first place? Walking assistive devices could be just the tool.

A key element of life quality for the ageing population is preservation of mobility. Being able to walk unassisted is essential for independent living and a crucial driver in maintaining quality of life and self-autonomy. In elderly populations, a wide variety of medical issues lead to loss of mobility, from stroke (CVA) to poorly healed fractures and general loss of muscle mass. Loss of mobility is therefore a key driver in the commonly reported issue of loneliness in elderly people – it makes sense that if it is a struggle to leave your house, you will do so less.

The first requirement for free walking is sufficient muscle strength, not just for walking but also for the associated tasks of day to day life, such as sitting-to-standing motions (and visa-versa) and ascending and descending stairs. For various reasons, the elderly population is subject to weakening muscular power and this is a larger driver in the difficulties that this population begins to face with such tasks.

LSRO (EPFL) in association with NCCR Robotics, propose an assistive device targeted for exactly this situation. Based on an exoskeleton, it is being designed to be usable at home, without permanent human assistance. It should allow normal walking without any impediment. It should provide assistive muscular power only when needed and without any specific command action other than natural motion of the legs.

For a first prototype, the focus has been on the hip joint, a key joint for walking assistance, and an assumption has been made that ankles and knees can still perform their normal functions. “Partial devices” such as those proposed by the Swiss team may offer promising solutions to issues faced by the elderly, who may experience excessive weakness in one joint (here, the hips), by providing a lighter weight and less invasive solution to full exoskeletons. Translating these needs into engineering specifications leads to the following requirements: A single motorised degree of freedom (pivoting of the femur in the sagittal plane), preserving the full mobility of the remaining degrees-of-freedom, high power and low weight, “transparency” for normal walking, no specific control action (such as a “joystick” command) of any kind.

The exoskeleton is designed to be easy to wear, without impeding movement.

The kinematic design of our device is such that torque is intrinsically high around the horizontal position of the femur (typical for sitting-to-standing, stair climbing) and is backdrivable in standing or walking posture (high compliance, “transparence”), thus allowing effortless and swift walking motion. The transmission ratio between motor and end-effector is thus intrinsically, by design, continuously adapted at an optimal value.

Our new types of actuators have been developed so as to fit the requirements of common activities of daily life. For instance, a variable reduction using a ball-screw and bar mechanism to assist different activities such as standing up from a sitting position or standard walking has been evaluated. A high torque is required during the sit-to-stand transitions when the flexion angle of the hip is around 70° from vertical. During walking, less torque is required but higher dynamics is needed. A smaller reduction ratio is therefore better adapted when the flexion angle is less important (i.e. in the walking range of motion). In order to create this specific transmission a ball-screw with an excavator-like mechanism was implemented.

The influence on gait of this kind of robotic hip orthoses are now being assembled and tested in a collaboration between LSRO at EPFL, SMS Lab at ETH Zurich and several clinical centres of elderly care. As the users are able to move on their own, it is very important that the exoskeletons do not. Indeed the added limitations imposed by a sub-optimally designed device may overshadow the benefits that it is intended to provide. The influence of different design parameters such as kinematic configuration, overall mass or user interface are therefore evaluated in collaboration with the Sensory-Motor Systems Lab (SMS) at ETH Zurich.

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ETH and the university of Zürich receive a 120 million dollar donation from ETH alumnus Hansjörg Wyss. (All photos: ETH Zurich)

ETH Zurich and the University of Zurich are founding a new translational research centre at the interface of medicine, science and engineering: the Wyss Translational Center Zurich. A USD 120 million donation from Dr. h.c. mult. Hansjörg Wyss to the two Zurich universities is making this possible. Through an interdisciplinary approach, the new centre aims to accelerate the development and application of innovative medical therapies and groundbreaking robotic systems.

ETH Zurich and the University of Zurich (UZH) are taking their long-standing partnership to a new level with a new translational research centre. The two universities are founding the Wyss Translational Center Zurich (WTZ) with funds donated by Hansjörg Wyss to the ETH Zurich Foundation. The core idea and motivation behind the initiative is to ensure that knowledge from basic and pre-clinical research can be applied in practice more quickly; in other words, an efficient translation into new medical therapies and innovative products.

The WTZ will initially include two technology platforms – one for regenerative medicine and the other for robotics. The centre will bridge disciplinary and institutional barriers and unite researchers across various disciplines, ranging from technology and medicine through to materials science, stem cell research and robotics. “Basic research in Switzerland is among the best in the world. However, it often takes a long time until the findings can be used to benefit patients. I want to help speed up this transfer with new models of interdisciplinary collaboration”, states Wyss, founder of the medical technology company Synthes Global and chairman of the Wyss Foundation.

The USD 120 million donation is a basic endowment to establish and operate the WTZ for the first seven years. ETH Zurich and UZH will provide personnel and infrastructure in the new centre. On the basis of the two translational technology platforms – regenerative medicine and robotics – the WTZ will commence operations in 2015 with a starting portfolio of four translational projects: Zurich Life Matrix, Zurich Heart/Ventricular Assist Devices, Zurich Liver and Zurich Eye. More groundbreaking transfer projects will be added over time. “The generous donation from ETH alumni Hansjörg Wyss provides a fantastic opportunity to use the many different scientific competences and skills here in Zurich to develop new medical and robotics products,” says ETH President Ralph Eichler. The new research centre will be based at both ETH and the University of Zurich and will be co-directed by professors Roland Siegwart (ETH Zurich) and Simon P. Hoerstrup (UZH). “Combined with the excellent basic research at the University of Zurich and ETH’s proven strength in technology development, the Wyss Translational Center will allow our two institutions to assume a very strong position among the international competition,” states Michael O. Hengartner, rector of the University of Zurich.

From research to product

ETH Alumnus Hansjörg Wyss with the two WTZ Co-Directors , Prof. Roland Siegwart (right) and Prof. Simon P. Hoerstrup.

Within the four starting research projects, the two partner institutions are aiming to develop new medical treatments, prototypes and innovative products over the coming years in order to improve the lives of patients and healthy people. An overview of the objectives of the four research projects:

Zurich Life Matrix: Development of in-vitro engineered human tissues that can regenerate and grow along with the organism. For example, scientists are growing blood vessels and heart valves in laboratories from human cells that can evolve in parallel with the heart (e.g. during the growth stages of a child) and have the capacity for self-repair. Existing solutions are usually of a non-living, prosthetic nature and, as a result, lead to complications that require surgical re-interventions often associated with substantial morbidity and mortality.

Zurich Heart/Ventricular Assist Devices: Development of innovative heart support pumps (ventricular assist devices). Many people today suffer from life-threatening heart problems. Artificial heart pumps support the diseased failing heart allowing patients to enjoy a good quality of life in the long term despite the lack of suitable donor hearts. However, there is still much room for improvement related to the biocompatibility, control, ergonomics and size of existing heart support pumps.

Zurich Liver: Development of innovative extra-corporeal perfusion systems. This will allow, for instance, a part of a patient’s liver to be grown outside the body and be transplanted back into the patient. This process would enable patients with serious liver diseases such as cancer to generate their own donor material and significantly decrease the demand for donor organs while increasing patient safety at the same time. The process could then be applied to allogenic transplantations and pave the way for one donor liver benefiting more than one patient.

Zurich Eye: Development of a camera-based positioning system that automatically creates maps of the environment and enables precise positioning. This system is intended to help autonomous vehicles and aircrafts navigate independently in disaster operations, transport and agriculture, and support people in various tasks.

This article originally appeared on ETH News.

The cardiologist sits in the control room next to the operating theatre and uses a joystick to steer a catheter through the patient’s blood vessel into the heart’s chambers to treat the cardiac arrhythmia precisely. With this robot-controlled surgical system, Phocus, the ETH spin-off Aeon Scientific won over a panel of 15 judges at this year’s Swiss Technology Award, presented last Thursday at the Swiss Innovation Forum in Basel. The company from Schlieren won the prize in the Start-up category. “We are delighted that our work has been recognised and appreciated,” said Dominik Bell, CEO of Aeon Scientific. “The award will help us market our product and find new investors and staff.”

Precise guidance with magnetic fields

Aeon Scientific originated from ETH Zurich’s Institute of Robotics and Intelligent Systems (IRIS). The start-up’s work focuses on making conventional surgical procedures safer and simpler. They develop devices that use magnetic fields to steer instruments remotely with millimetre precision inside the human body. The foundations were laid by the team of ETH professor Bradley Nelson, a co-founder of Aeon Scientific. The scientists began their research into a magnet-controlled surgical system at IRIS in 2003, before establishing the spin-off in 2010. The first Phocus system will be put into operation in January 2015 in Zurich.

Bell believes this steering system based on magnetic fields could also be used in other areas of medicine. He is hoping that the company can establish a number of other robot-controlled medical treatments, not just for cardiology. He says that magnetic forces could be used to steer a wide variety of instruments such as catheters, guidewires and endoscopes, or even capsules containing active ingredients, directly to the source of an illness within the body.

Robohub is an online platform that brings together leading communicators in robotics research, start-ups, business, and education from around the world. Learn more about us here. If you liked this article, you may also be interested in:

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Brad Nelson heads the Institute for Robotics and Intelligent Systems at ETH Zurich, where they focus on creating these nano devices inspired by the biological mechanisms of bacteria such as E. coli and salmonella.

Brad Nelson. Photo credit: ETH Zurich/Stéphanie Marie Couson

Brad Nelson is a Professor of Robotics and Intelligent Systems at ETH Zurich – The Swiss Federal Institute of Technology, Zurich. His primary research focus is on microrobotics and nanorobotics emphasizing applications in biology and medicine.

He has been the Department Head of Mechanical and Process Engineering at ETH, Chairman of the ETH Electron Microscopy Center, and is a member of the Research Council of the Swiss National Science Foundation. He is also a member of the board of directors for three Swiss companies.

More info:

Institute of Robotics and Intelligent Systems (IRIS)
Multi-Scale Robotics Lab (MSRL)
Brad Nelson’s Homepage
Brad Nelson’s TedX Talk

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Search and rescue operations are increasingly using drones, and the speed and ease with which UAVs can be launched is especially important when applying them as an emergency response tool. Jonathan Cheseaux, a masters student from Switzerland has developed a system to help drones home in on the location of people in need of rescue, and Dronologista had an opportunity to discuss the project with Jonathan via email. Here is what he says:

Dronologista: How did you come up with the idea?

Jonathan: The main goal of the project was to provide WiFi connection to people on the ground (in disaster areas, where there is no more connectivity), using swarms of flying robots. By analyzing the data collected by the WiFi antenna embedded in the plane, we thought about using this information to localize people and moving the plane around so that the connection is better.

Dronologista:  Have you been working on it alone or it was a team effort?

Jonathan:  A team effort. I was working with two people, Stefano Rosati, a postdoc, and Karol Kruzelecki, a graduate student. They helped me a lot to fulfill the project’s goals.

Dronologista:  How does this system work?

Jonathan:  The UAV sniff WiFi packets periodically broadcast by smartphone (if WiFi is switched on). The smartphone broadcast so-called “probe requests” to discover which WiFis are in range. We extract the signal power of these packets (RSSI) and use the GPS position of the plane to localize the users.

Dronologista:  Has it been tested, and if yes, how?

Jonathan: We flew the UAV around EPFL‘s campus and tried (and succeeded) to find the position of a smartphone randomly placed somewhere on a building with a satisfying precision.

Dronologista: What are potential problems?

Jonathan: If the WiFi of the smartphone is not switched on, we cannot localize the user. Also the signal can get scrambled by a lot of factors, such as buildings reflecting the signal, weather conditions, plane’s orientation, etc. In the case of an earthquake for example, if the victim is buried under several meters of concrete, the WiFi signal will not be detectable. Also Apple announced that they will randomize the MAC address while sending probe requests in iOS 8, and this will make the localization quite impossible because now we rely on the fact that a MAC address is unique for a user, and can thus fully determine which person we are localizing.

http://youtu.be/7ysg-m7kV14

Dronologista: Were you contacted by any organization yet?

Jonathan: I’ve been invited to the UAV Show 2014 (London), they want me to give a small speech about my project during the conference. I’ve also been contacted by several companies that want to commercialize search and rescue drones.

Dronologista: What are future steps for this system?

Jonathan: Enhance precision by conducting more real life testing, maybe use GSM data as well (IMSI catcher), but due to legal concern it could be difficult to implement. The real improvement will be to use avalanche transceivers to find avalanche victims. I really want to work on that after my internship.

Dronologista: What are other projects you are working on, that you want to share?

Jonathan: During my bachelor studies, I implemented a virtual reality project using Kinect and some physics engine. The goal was to project the user in a virtual environment and allow him to interact with [the environment] (shoot a virtual ball, smash a wall), as well as draw interactive shapes with the only use of hand gestures (drawn shapes we bound to the physics engine so that it also falls/bounces etc.). Last semester, I lead a project on Bitcoin trading. We’ve implemented sentiment analysis on tweets talking about bitcoin to probe the market’s mood and used time-series analysis to work directly on the bitcoin stock market. That was a really cool project. I’m going to start my master thesis soon, in which I will develop a smart search engine that will automatically classify documents, display augmented information, context, etc. I’m not sure yet what the project will be exactly, but it is definitely about machine learning.

***

Dronologista wishes Jonathan and his team great success with their projects, and expects to hear more good news about their endeavors soon. And so should you.

For further reading check EPFL news, SkyNews, and the Swarming Micro Air Vehicle Network (SMAVNET II) project page.

Noonee® is a new Start Up company coming out of research in robotics in Switzerland. Aimed at solving healthcare problems within the manufacturing industry, noonee adopts a Chairless Chair® approach.

Within the manufacturing industry, keeping employees healthy has been a major concern and challenge for many companies around the world for a long time. Jobs often involve spending long periods of time bending and crouching and as a result can leave staff with substantial back and knee problems. Of 215 million industry sector workers in the EU, a staggering 85 million are reported to suffer from muscle related disorders. Market solutions that are currently available may also pose problems as they limit short term tiredness by taking all the weight of the user, which can lead to muscle weakening. What is needed is a product that can support staff working on production lines while keeping them healthy.

Coming out of NCCR Robotics lab, the Bio-Inspired Robotics laboratory at ETH Zurich, Switzerland, noonee® is a revolutionary start-up business aiming to address this significant social issue that previous solutions have not dealt with successfully. The idea is to provide an exoskeleton that supports the weight of the user only when they feel tired , rather than continuously taking on this weight – meaning that the wearer is using their muscles and actively, rather than passively, sitting.

The “chair” is not a chair as we know it, but more of an exoskeleton for the legs with a belt to attach it to the hips and straps that wrap around the thighs. The slim structure has joints that allow the wearer to move freely, but when the wearer is in a position they wish to stay in for a long time (e.g. crouching under a car on a production line), this position can be fixed, meaning that the wearer does not need to use the same muscle groups for long periods of time to hold the position. The advantage of such a structure is that it can be worn anywhere and can also be used when standing and walking. This reduces the space required as compared to a traditional chair and reduces the hassle when compared to other solutions, such as chairs that are strapped to the user. The Chairless Chair® is currently still in prototype and the current version requires the user to fix a position by crouching down into the required position and pushing a button. It is hoped that future iterations of the Chairless Chair® will be actuated to allow the system to become intelligent and understand the intention of the user, allowing it to be fixed into position without any additional input from the wearer.

If you’re interested and want to be a part of prototype testing, check out their website and get in touch. Feel free to also ask questions in the comment section below.

Robohub is an online platform that brings together leading communicators in robotics research, start-ups, business, and education from around the world. Learn more about us here. If you liked this article, you may also be interested in:

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See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

Microsoft has been investing in Swiss research for years, and now the US technology company is renewing its longstanding collaboration with EPFL and ETH Zurich. Microsoft will provide one million Swiss francs per year in funding for IT-related research projects at the two universities over a period of five years. The collaboration is a continuation of a project launched in 2008 that focused on embedded technology software solutions and prototypes. The new collaboration will now broaden the areas of computer science and deepen the collaboration between the three partners.

Scientists in Lausanne and Zurich submitted 27 proposals, seven of which were selected by the steering committee. Among the successful projects:

Interacting with flying robots

Otmar Hilliges, a 34-year-old assistant professor, is one of the successful project applicants. The young computer scientist from ETH Zurich studies the interaction between people and computers. For his project, he and Dr. Shahram Izadi from Microsoft Research are investigating how flying robots can work and interact with people in active scenarios. Specifically, they want to develop a platform that enables flying robots to do more than just recognise people and navigate their way around them. Thanks to their algorithms, the robots should be able to react to gestures and touch as well.

Energy-efficient memory systems

At the EcoCloud center at EPFL, Dr. Edouard Bugnion and Professor Babak Falsafi are carrying out research into energy-efficient memory architectures for data centres that can handle huge amounts of data. To do this, they are combining thousands of energy-efficient micro-servers in a way that enables them to access the memories of the other servers with a minimal time delay. The two computer scientists are working with Dr. Dushyanth Narayanan and other scientists from Microsoft Research in Cambridge to develop new applications for this system, known as Scale-out NUMA.

2022 update: A new, one-wheeled version of the Cubli has been developed. The one-wheel Cubli is a three-dimensional pendulum system that can balance on its pivot using a single reaction wheel, as it is shown in this article.

2014 update: My colleagues at the Institute for Dynamic Systems and Control at ETH Zurich have created a small robotic cube that can autonomously jump up and balance on any one of its corners .

This latest version of the Cubli (2014) can jumping up, balance, and even “walk”. This new version is self contained with respect to power and uses three slightly modified bicycle brakes instead of the metal barriers used in the previous version. We are currently developing learning algorithms that allow the Cubli to automatically learn and adjust the necessary parameters if a jump fails due to the deterioration of the brakes and changes in inertia, weight, or slope of the surface.

This robot started with a simple idea:

Can we build a 15cm sided cube that can jump up, balance on its corner, and walk across our desk using off-the-shelf motors, batteries, and electronic components?

There are multiple ways to keep a cube in its balance, but jumping up requires a sudden release of energy. Intuitively momentum wheels seemed like a good idea to store enough energy while still keeping the cube compact and self-contained.

Furthermore, the same momentum wheels can be used to implement a reaction-torque based control algorithm for balancing by exploiting the reaction torques on the cube’s body when the wheels are accelerated or decelerated.

Can this work?

The first step in creating the robot, therefore, was to look at the physics to figure out if a jump-up based on momentum wheels was possible. The image below shows some of the math to figure out the Moment of Inertia (MOI) of the wheel and full cube.

This mathematical analysis allowed a quantitative understanding of the system which allowed to inform design choices, such as the trade offs of using three momentum wheels vs. a design with a momentum wheel mounted on each of the six inner faces of the cube.

Another outcome of this analysis was a good understanding of the required velocities of the momentum wheel to allow the cube to jump up, and the torques required to keep the cube in balance. Both factors were critical for the next steps: Determining the required hardware specs.

Specs and hardware design
Given the required velocities and torques determined above, it was clear that the momentum wheel’s motor and gearbox would be a major challenge for creating the robot. Using the mathematical model allowed to systematically tackle this problem by allowing a quantitative analysis of the trade-offs between higher velocities (i.e., more energy for jump-up) and higher torques (i.e., better stability when balancing).

This mathematics-driven hardware design resulted in detailed specs for the robot’s core hardware components (momentum wheels, motors, gears, and batteries) and allowed a CAD design of the entire system.

Part of this step was the design of a special brake to suddenly stop a momentum wheel to transfer its energy to the entire cube and cause it to jump up.

The photo to the left shows an early design of this brake, consisting of a screw mounted on the momentum wheel, a servo motor (shown in black) to move a metal plate (in blue) into the screw’s path (in light brown), and a mounting bracket (in light brown) to transfer the momentum wheel’s energy to the cube structure. The current design uses a combination of hardened metal parts and rubber to reduce peak forces.

2D prototype
To validate the mechanics and electronics of the jump-up and balancing strategy and prove feasibility of the overall concept a one-dimensional version was built:

The results obtained with this 2D version of the cube were published in an IROS 2012 paper.

The final robot
Following successful tests with the 2D version, a full robot was built. The result is Cubli, a small cube-shaped robot, named after the Swiss-German diminutive for “cube”.

As you can see in the video, Cubli can balance robustly.

However, first jump-up tests showed that the stress resulting from a sudden braking of the momentum wheel led to mechanical deformations of the momentum wheels and aluminium frame. This made repeated jump-ups of the whole Cubli impossible without part replacement. It was therefore decided to tweak the structure and breaking mechanism to reduce the mechanical stress caused by the jump-up.

In addition to balancing, my colleagues are now investigating the use of controlled manoeuvres of jumping up, balancing, and falling over to make the Cubli walk across a surface.

Note 1: This post is part of our Swiss Robots Series. If you’d like to submit a robot to this series, or to a series for another country, please get in touch at info[@]robohub.org.

Note 2: This work was done at the Institute for Dynamic Systems and Control, ETH Zurich, Switzerland and was funded in part by the Swiss National Science Foundation (SNSF), grant number 146717.

Note 3: If you have questions, post them below and we’ll post answers.

Some more photos:

Thanks Gajan!

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Unlike larger robots, microrobots for applications in the body are too small to carry batteries and motors. To address this challenge, we power and control robots made of magnetic materials using external magnetic fields. Developed at ETH Zurich’s  Multi-Scale Robotics Lab (MSRL), the OctoMag is a magnetic manipulation system that uses electromagnetic coils to wirelessly guide microrobots for ophthalmic surgery. 

The OctoMag is capable of generating magnetic forces and torques in three dimensions, and is physically restricted to a single hemisphere to allow easy access for patients and physicians. Using an early OctoMag prototype, ex-vivo experiments were performed in pig eyes to study the navigation tasks required for retinal surgery. Following these experiments, a next-generation system was built to accomodate a small animal head, allowing for in-vivo trials. With this system, mobility experiments were conducted in which a microrobot with a diameter of 285 µm (about four times the width of a hair) was navigated reliably through the eye of a rabbit, demonstrating the feasibility of using this technology in surgical applications.

Robots are capable of exploring many environments that are difficult, if not impossible, for humans to reach; the edges of the solar system, the planet Mars, the inner depths of volcanoes, and bottom of the ocean are just some examples. The goal of these robotic explorers is to obtain knowledge about our universe and to answer fundamental questions about the nature of life on Earth. Recently, micro- and nanotechnologies have fueled an exciting expansion of this field by allowing scientists to use robots to probe life at much smaller scales. Nanorobotic systems for exploring the structures of biological cells, and robotic motion planning strategies for the investigation of protein folding, are two compelling examples of the intermarriage between robotics and nanotechnology. Such efforts and others like them illustrate how several areas of science and engineering are rapidly converging to create a new, interdisciplinary approach to research that promises to revolutionize our understanding of the world around us.

While many envision a future in which intelligent nanorobots navigate throughout our bodies searching for and destroying disease, researchers are still far from realizing such advanced technologies.  However, progress is being made, and the past decade has seen impressive advances in the fabrication, control, and delivery of power to tiny motile devices.

The MiniMag is a research tool for studies at the micro scale. As a scaled-down version of the OctoMag, the MiniMag can be integrated into an upright or inverted microscope. The eight electromagnetic coils are slightly tilted and can be positioned very close to each other due to their smaller size, and, by reducing the magnetic workspace to one cubic centimetre, much higher forces can now be achieved. Combined with high-resolution optics, the MiniMag system allows for single cell manipulation and studies at the tissue level in 3D.

From the microscale to the nanoscale
As size decreases to the nanoscale, wireless magnetic manipulation becomes increasingly challenging. The magnetic force drops by a power of three as it scales with volume, and fluidic drag forces begin to dominate as inertial forces become negligible. While a number of robotic swimming methods have been proposed to aid mobility at relatively small scales, many of these methods rely on reciprocating motions and do not scale downwards.

More than three billion years ago, bacteria evolved a swimming strategy at micrometer dimensions that nature has had difficulty improving upon, and in 1973, H.C. Berg and R.A. Anderson first described a swimming technique that uses rotating helical flagella. Inspired by this work and the flagellar motion of bacteria such as Escherichia Coli, we have recently developed artificial bacterial flagella (ABF). Our ABF represents the first demonstration of wireless swimming microrobots similar in size and geometry to natural bacterial flagella, and are many orders of magnitude smaller than existing artificial helical swimmers. With the help of 3D-laser-nanolithography, arrays of thousands of such swimmers can now be fabricated. A careful choice of materials allows for cellular interaction, and fluorescent labeling of the device assists with localization and tracking. We are pursuing applications such as the treatment of breast cancer and cerebral infarctions.

The potential impact of this technology on society is high, particularly for biomedical applications, though many challenges remain in developing micro and nanorobots that will be useful to society. An overarching requirement for achieving breakthroughs in this area is the need to bring together expertise from a wide variety of science and engineering disciplines.  Robotics brings expertise in the planning and control of mechanisms with many degrees of freedom in uncertain environments. Nanotechnology teaches innovative approaches to fabricating nanoscale machines. In addition, biomedical imaging advances are needed, as is fundamental insight into the nature of fluid dynamics at very small scales.  Medical professionals must be tightly integrated into the development cycle, and experts in developing business models and intellectual property must be closely consulted.

About the researchers
Brad Nelson’s Multi-Scale Robotics Lab (MSRL) at the Institute of Robotics and Intelligent Systems, ETH Zurich, Switzerland, is a highly multi-disciplinary research group that leverages advanced robotics techniques to create intelligent machines that operate at micro- and nanometer scales.  At the MSRL, a team of nearly 30 scientists pursues a dynamic, robotics-oriented research program involving several emerging areas of science and technology.  The technical backgrounds of the scientists in the lab span such diverse fields as materials science, physics, biology, electrical and mechanical engineering, and computer science.

The materials scientists in the lab focus mainly on developing the tools and processes required to fabricate and assemble microscale robots and nanoscale robotic components.  Many of these systems are then used in the study of biological environments, including the investigation of molecular structures, cellular systems, and organism behavior.  Other members of the MSRL research team are focused on the design and implementation of systems that wirelessly control these microrobots.  Potential applications are numerous and diverse, including microrobotically-assisted surgery, magnetic micromanipulation at the cellular level, low Reynolds number locomotion, wireless power delivery, electrostimulation of biological materials, and micro- and nanostructure fabrication and characterization.

The MSRL develops systems for controlling micro- and nanorobots in liquid and pursues various applications for these devices.

[Edited by Hallie Siegel]

If you liked this article, you may also be interested in:

• Crowdsourcing new strategies for cancer treatment: Towards swarming nanobots
• Medical robotic systems market to reach $13.6 billion by 2018
• Robots Podcast: Curved Artificial Compound Eye
• Micro-robotics and medicine: Interview with Toshio Fukuda

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

“The whole is greater than the sum of its parts” — a catch phrase that aptly expresses the Distributed Flight Array: a modular robot consisting of hexagonal-shaped single-rotor units that can take on just about any shape or form. Although each unit is capable of generating enough thrust to lift itself off the ground, on its own it is incapable of flight much like a helicopter cannot fly without its tail rotor. However, when joined together, these units evolve into a sophisticated multi-rotor system capable of coordinated flight and much more.

In the beginning
In the summer of 2008, Professor Raffaello D’Andrea at the Institute for Dynamic Systems and Control at ETH Zurich envisioned an art installation consisting of single-rotor robotic units that would self-assemble on the ground and then perform a joint task that would otherwise be impossible to achieve on its own — flight. This modular flying vehicle would then break apart in the air and then repeat the process over again, but in a new randomly-generated configuration.

Feasibility study
The number of challenges faced in designing and implementing such a system are many. We first wanted to be sure, however, that the concept was indeed feasible. Making some realistic assumptions about the system we performed some back-of-the-envelope calculations and created a linear dynamics model of the vehicle in order to provide us with some intuition about its physical dynamics. From this, a control strategy was devised. We then simulated the closed-loop system under a variety of disturbances, providing us with a general understanding of the physical requirements needed to successfully execute the project.

Design and implementation of the physical system began in the fall of 2008 as part of a design project class at ETH Zurich. The class consisted of eight graduate-level students from mechanical, electrical, and software engineering, as well as technical staff and instructors, including myself. Our task was to design and build a functional prototype that would demonstrate three key abilities of the system: (1) docking, (2) coordinated ground mobility, and (3) coordinated flight. In accomplishing each of these tasks, we would in turn validate our model and control strategy, and likely discover limitations to the system we did not foresee.

The project was no doubt challenging, and the timing constraints imposed by the class did not work in our favour. Our initial hope was to demonstrate each of the key abilities using a single set of vehicles and to demonstrate coordinated flight in several configurations. Our goals were too ambitious under the framework of this class and therefore loosened our requirements. By the summer of 2009 (a few months after the class had ended), we succeeded in demonstrating each of these key abilities, and ultimately, the project’s feasibility.

Towards the end of the above video, you will notice one of the many limitations of the system: its inability to control its altitude (or height off the ground). You may also notice that both flying and driving capabilities were separated in order to make the vehicle lighter for flight. Its primary limitation, however, was its inability to demonstrate coordinated mobility for randomly assembled configurations. The units themselves lacked the ability to communicate on each of their sides, and even if this were possible, we did not yet have any way of automatically generating the appropriate control strategy for the assembled configuration. For our demonstration, each unit was pre-programmed for a particular configuration and the controller was tuned by hand. This, however, was just the tip of the iceberg for the long list of requirements needed to successfully achieve our final goal.

Design iterations
With the design project class under wraps, and feasibility of the system demonstrated, the next step was to engineer a truly modular system capable of coordinated mobility — both on the ground and in the air. This was by no means a straightforward process; if it was, it wouldn’t be considered research. One additional revision of the vehicle was created prior to arriving at the current design.

In designing Revision 1, one of our major goals was to integrate both driving and flying capabilities. This required us to rethink the mechanical chassis and to design with a sufficient thrust to weight ratio in mind. Although light-weight and mechanically robust, the ethyl polypropylene foam chassis we used in the proof-of-concept vehicle was difficult to manufacture and our experience led us to switch to a different material. We opted instead for constructing the chassis out of laser-cut acetal plastic, a higher-powered flight motor, and a new propeller. This resulted in a very robust chassis, which was easy to fabricate in-house, and it provided sufficient thrust for the purposes of lift and control effort. What we failed to consider, however, was the stiffness of the chassis and manufacturing variability of the rotors. Only after completing the design of Revision 1 and producing several units did we discover that the vibrating modes in the chassis caused by aerodynamic turbulence from the propellers saturated the onboard rate-gyroscope sensors, which was needed for closed-loop control.

It was also important in this revision to demonstrate communication on each of its six sides. We successfully accomplished this using infrared transceivers mounted to each connection interface. However, we later discovered interference issues when conducting experiments with our vehicle within the environment of a 3D motion capture system (needed for ground truth measurements), which uses a similar frequency of infrared light to illuminate markers that it tracks in order to estimate the pose for the object of interest.

On top of this was the need to shrink the size of the electronics such that it would fit within the protected volume of the chassis. We were motivated by recent manufacturing possibilities in creating flexible printed circuit boards, and locked on to this scheme. When it came around to producing the boards, however, the lead-time for such services in relatively small quantities was much too long for our requirements — we wanted to be able to prototype and have a quick turn-around on our designs. We therefore had to redo parts of the design for a standard printed circuit board.

There was also the suggestion to first fly the system using a 3D motion capture system for measurement feedback. Since these measurements were very precise and relatively fast, we could by-pass the onboard estimation problem and focus only on the control problem. This, in fact, worked against us for two major reasons: (1) as described before, the infrared light from the 3D motion capture system interfered with inter-communication; and (2) measurement information (or control information) needed to be transmitted to the vehicle wirelessly for control purposes, which at the time of development (using WiFi) generally incurred a lot of latency and packet loss.

There was a lot that needed to be redesigned, a lot that was assumed, and there was pressure to get research publications out. In Revision 1, we tried to jump over too many hurdles at once and what we delivered was a semi-functional system — functional under optimal operating conditions, but failed to work most of the time. However we learned many things, in particular it focused our attention on parts of the design that we overlooked. This laid the ground work for Revision 2.

In Revision 2, we redesigned the chassis and thrust generation unit (i.e. propeller and flight motor) from scratch, but kept most of the power and control electronics the same. Using some of the most recent advances in manufacturing technology, the chassis was 3D printed this time around, enabling us to design with very little fabrication constraints and has a relatively quick turn-around time. The first factor was very important because of the number of tightly integrated components held together within a single unit. The second factor enabled us to quickly test a design and re-iterate as necessary.

This time around, we stepped through each phase of the design systematically. The new flight motor and propeller was tested to ensure that it produced a sufficient amount of thrust and produced little vibration within the chassis, which we tested using the rate-gyroscope sensors from Revision 1. Using two units and electronics from Revision 1, we tested the closed-loop behaviour around a single axis of rotation by mounting the two units on a horizontal pivot. This alone required a few iterations of the chassis, which in the end we managed to get right.

Ignoring the intercommunication problem, we ploughed ahead and constructed six complete units for flight. In this revision, we demonstrated coordinated flight for a variety of configurations. The flight controller was computed ahead of time and sent wirelessly to each unit prior to flight.

Knowing that the chassis and thrust generation unit was sound, we then went ahead and integrated driving capabilities and intercommunication into the units. In terms of the latter, we redesigned the intercommunication scheme, employing a hard-wired interface instead of an infrared wireless link and utilized an electrical bus to clean up the mess of communication lines we had in Revision 1. A detailed description is given in the next section.

Designed from the ground up
Each unit uses a single 32-bit 72 MHz microcontroller to interface with all of the onboard sensors, actuators, and communication peripherals. The same microcontroller is also used for performing all of the computation necessary for estimation and control — there is no computation that is performed offboard. An interchangeable wireless module (either WiFi or proprietary frequency hopping spread spectrum) allows us to communicate with each unit (e.g. telemetry and user commands); in the case where external sensors are used (e.g. 3D motion capture system), the data can be sent to the units over this wireless link.

Standard on most aerial vehicles is a 3-axis rate-gyroscope, which is used for measuring body angular velocities, as well as estimating the attitude of the vehicle in flight. An infrared distance measurement sensor is used for measuring the distance of a unit to the ground. Not only is this used for estimating the altitude of the vehicle, but if units share their distance measurements with one another they can also estimate the vehicle’s tilt when flying over a flat surface.

We have designed each unit with magnetic interfaces, located along each of its six sides. This allows a unit to passively self-align with its connected peers. The connection strength, however, is in fact not very strong. This was intentional, as it clearly demonstrates the need for cooperation between individual units in order to achieve flight — without it, the vehicle would simple rip itself apart before take-off. To successfully accomplish this, the flight control strategy must minimize the shear forces occuring between interconnected units during flight.

Also located on each of its six sides are three gold push-pins. Together with the magnets, this interface behaves similarly to the Apple MagSafe power connector, except that this interface is used to provide a means for hard-wire communication between neighbouring peers. With this, we developed our own network layer to handle inter-unit communication, as well as algorithms for routing packets, time synchronization, information fusion, etc. on a resource limited embedded system. Units are also able to communicate with one another in plane at a distance using infrared wireless transceivers, which is primarily employed for self-assembly purposes.

Each unit is equipped with three omni-directional wheels, allowing it to move on the ground with a high degree of maneuverability and to be able to move when assembled together. One of the nice things about using 3D printer technology is that the omni-wheels could be printed as a single piece, without having to assemble any components.

Positioned at its centre is a fixed-pitch propeller, capable of generating enough thrust to lift a single unit off the ground. All units are physically identical except for the handedness of its propeller. Some are clockwise and some are counterclockwise — this is needed in order to cancel out the aerodynamic torques in flight. Finally, a high energy-density Lithium-Ion Polymer battery is used to power all the electronics and actuators contained onboard.

Coordinated flight
The units can move around on the ground, self-assemble, generate an adhoc mesh network in order to communicate with one another, but the most striking feature of the Distributed Flight Array is its ability to fly in an unlimited number of configurations.

Recall that the units are being held weakly together with magnets. Thus, each unit is generating the appropriate control effort necessary to keep the vehicle in flight while minimizing the shear forces between individual units. What is most surprising is that the units themselves do not necessarily need to communicate with one another during flight.

The only information that a unit needs for flight is its local sensor data and its position with respect to the vehicle’s centre of mass. This can be computed if each unit knows the physical configuration of the vehicle. In order for a unit to determine this on its own, each unit can work out its relation to neighbouring units by sharing appropriate information. By forwarding this information around the network, each unit can arrive at the physical configuration of the vehicle, much like how one might establish his/her family tree.

Assuming a rigid body for the vehicle, which was taken into account when designing the chassis, local sensor information provides a unit with a rough estimate of the vehicle’s tilt and altitude. And knowing its position with respect to the centre of mass, it’s straightforward to work out the appropriate control effort needed to counter-act any disturbances. We avoided using a linear quadratic regulator or other optimal control strategies in favour of something much more straightforward, and as it turns out the method is also scalable. We employ a cascaded parameterized controller, consisting of tuning parameter that are physically intuitive (i.e. closed-loop natural frequency and damping ratio) for each degree of freedom.

Now, it wouldn’t be reasonable to hand-tune the controller for each and every configuration. We instead developed a means for automatically computing the tuning parameters for any flight-feasible configuration of the vehicle that would result in best flight performance. In carefullly analyzing the parameters obtained for a variety of configurations, we then developed a scalable method for mapping the configuration of a vehicle to its approximated optimal control tuning parameters.

Rewards and reality
A lot challenges, a lot of frustration, but also a lot of reward. What started as an idea is now a reality. Although we have not necessarily shown it to reenact the Concept Animation shown above, it is certainly capable of performing each of those tasks. What we have here is a piece that suitably demonstrates cooperative behaviour.

The success of this project would not have been made possible without support from the Swiss National Science Foundation, as well as the countless number of hours spent by students and technical staff — they all deserve as much credit. The Distributed Flight Array is currently being used at the Institute for Dynamic Systems and Control at ETH Zurich as a modular robotics platform for investigating algorithms in distributed estimation and control. Updates regarding the project’s status and a list of those involved with the project can be found on its home page.

Who’s Currently Involved: Raffaello D’Andrea, Maximilian Kriegleder, Igor Thommen, and Marc A. Corzillius

Photo credit: Raymond Oung

Note: This post is part of our Swiss Robots Series. If you’d like to submit a robot to this series, or to a series for another country, please get in touch at info[@]robohub.org.

If you liked this article, you may also be interested in:

• Insect-inspired flying robot handles collisions, goes where other robots can’t
• The Distributed Flight Array: Modular robots that self-assemble, coordinate and take flight
• Designed to mingle: Rezero ballbot’s smooth moves can handle a crowd
• Cubli – A cube that can jump up, balance, and walk across your desk

See all the latest robotics news on Robohub, or sign up for our weekly newsletter.

The Airburr, a light-weight flying robot from the Laboratory of Intelligent Systems (my PhD lab) at EPFL, was designed to fly in cluttered environments. Unlike most flying robot, which avoid contact at all cost, the Airburr interacts with its environment to navigate. Just like you might trail your hand along a wall to find your way in the dark, the robot can bounce of walls or follow them without crashing to the ground. In case of a crash, it also has a mechanism to pick itself back up and fly away. I’ve added past videos of the Airburr in action below.

The Airburr can now perch, thanks to a gecko-inspired adhesive pad that is mounted on a mechanism within the structure of the robot. This work was presented last week and ICRA (read the paper here). The gecko pad can be deployed on demand when perching is initiated. Perching allows the robot to power down and save energy, while still providing an aerial perspective that is useful for real-world missions such as search and rescue.

The work was done in collaboration with Mettin Sitti from Carnegie Mellon University, an expert in dry adhesive materials, and was inspired by the hairy feet of geckos. Rather than using claws or sticky substances to climb up walls, geckos use van der Waals forces between the tip of each hair and the surface to cling to. The artificial hairs used on Airburr have a diameter of 40um and a height of 100um with mushroom tips of 80um.

Airburr Crash Recovery

Uprighting Mechanism

How do you like to go up in a swing,
Up in the air so blue?
Oh, I do think it the pleasantest thing
Ever a child can do!

Child’s Garden of Verses by Robert L. Stephenson

If you’ve ever been a child, chances are that you’ve spent some of your childhood on a swing. And at some point during that time you have probably found out how to move your arms, legs, and body to go higher and higher, without any external help from a friend or parent pushing you – you learned how to pump a swing.

Flavio Fontana, Master student at the ETH Zurich’s Institute for Dynamic Systems and Controls, has taken this concept and used it to control a robot. To make things more challenging, his robot does not just swing, but simultaneously juggles a ball. And, using some neat math to push the idea even further, he and his supervisors Philipp Reist and Raffaello D’Andrea have designed the robot to swing and juggle without cameras – and without ever dropping the ball.

The result of their research is the Swinging Blind Juggler, a robot that juggles a ball from side to side with an actuated paddle attached to a pendulum. The robot is called “blind”, because it has no cameras to “see” the ball. In fact, the Swinging Blind Juggler has no sensors to detect the ball at all.

Here is what Flavio has to say about his video:

In this video, we propose an elegant control strategy for a Swinging Blind Juggler. The key idea is to exploit the dynamic coupling between the motion of the paddle and the pendulum. Children on a swing intuitively use this dynamic coupling to control their amplitude. In a similar way, we control the pendulum with appropriate paddle motions.

So how does this work?

Flavio explains that four conditions must be met for successful juggling:

• First, the paddle used to juggle the ball must have a specific concave shape. This shape will always push the ball back towards the ideal flight path if the ball impact happens to be off-center.
• Second, the paddle has to decelerate as it strikes the ball. This helps to keep the ball bouncing at a consistent height: If the ball flies too high, it will hit the paddle later and hence at a lower speed. Conversely, if the ball flies too low, it will hit the paddle earlier and hence increase the ball’s height on the next bounce.
• Third, the paddle always has to strike the ball at right angles. This ensures that the ball always flies off into the right direction, towards the other side of the swinging motion.
• And fourth, the pendulum must be synchronized to the ball motion. In other words, the pendulum has to reach the peak of its swinging motion at the right time to strike the ball.

To guarantee all of the above, the researchers first derived a mathematical model of the desired motion. Based on these models, they came up with a hardware design that includes a parabolic plate to stabilize the ball’s impact points on the paddle (the first condition), a decelerating paddle motion that stabilizes the ball height (the second condition), and a mechanical mechanism based on four linked bars that automatically tilts the paddle to the right angle for all juggling amplitudes (condition number three).

To meet condition four (to swing back and forth at the right rhythm to hit the ball) the robot can use the same linear motor used to create the decelerating paddle motion for condition two – as long as it still strikes the ball with the right decelerating motion at its peaks. Similar to a child on a playground swing, the robot must raise its body as the swing passes through the lowest point and lower it near the extremes of the motion to pump the swing and swing higher.

The result of the precisely designed hardware setup and control algorithms is a complex motion that’s beautiful to watch – and that blindly juggles a ball from side to side.

To learn more about blind juggling robots, have a look at www.blindjuggler.org.

Note: This post is part of a series that decribes robots developed in Switzerland. If you’d like to contribute a robot to this (or another country’s) series, get in touch at info[@]robohub.org. Like this series? Read more about Swiss Robots!

Designing robots that can function outside of controlled, factory environments isn’t easy. When those environments have people in them, they are especially unpredictable and difficult for a robot to navigate.

Enter Rezero: a compact ballbot that can fluidly drive in any direction without prior orientation. Similar in size and shape to a human, Rezero can stabilize, instantly accelerate, avoid obstacles and turn around its own axis. It can also be programmed to follow a path, or a person at a constant distance, and it can even recover from jostles, making it ideal for navigating crowded environments like tradeshows, restaurants, offices and airports.

Possible Rezero applications: personal mobile medical device, telepresence tour guide, personal transportation.

It’s easy to imagine it one day being used to unobtrusively serve drinks at a cocktail event, as a personal mobile device for intravenous equipment at a hospital, or topped with a telepresence device and acting as a museum tour guide. Rezero could even one day rival the Segway as a personal transportation device.

A master of fluidity

Like an inverted pendulum, Rezero (left) balances on a spherical ball; three omniwheels (right) transfer motor action to the ball below.

Rezero’s agility comes from a propulsion and stabilization mechanism that keeps the device balanced on top of a single spherical wheel, like an inverted pendulum; it’s kept from falling over by constantly moving its contact point below its center of gravity.

A sensor called an Inertial Measurement Unit (IMU) measures Rezero’s tilt angle, which is used by an onboard stabilizing controller to compute what kind of motor action is required to keep the system stable. Instructions are then sent to electric motors that actuate three special wheels (called omniwheels), which in turn transfer forces to the sphere below: forces are applied in the rolling direction, but allow for free motion in the lateral direction; opposing each wheel is an arrestor that keeps the ball tightly in place. This process of measuring, computing, and actuating happens 160 times per second, and the underlying controller is key to achieving robust and dynamic movement.

Its ability to quickly respond to a changing environment is what makes Rezero so suitable for human environments, and according to Rezero’s creators, achieving this robustness was their most challenging task. Rezero’s controller is derived from a three-dimensional mathematical model of the system, and can combine complex and fluid movements around all axes. Compared to other ballbots, which can only lean a few degrees, Rezero can tilt up to 17 degrees as it leans into a curve at high speeds.

But getting there wasn’t easy. Rezero was developed in 2009/2010 as an educational project at the Autonomous Systems Lab at ETH Zurich,  and the 13 undergraduate students on the team were responsible for everything from concept to engineering, manufacturing and budgeting.

According to project leader Péter Fankhauser:

“It was the moment we got Rezero to balance for the first time that struck me the most. We got to know the system and work with it and were able to observe how its capabilities improved every day.”

Michael Neunert, his fellow founding team member agrees:

“The development phase was a very intense time. We only had nine months to sketch out our ideas and build Rezero as we see it today.”

Rezero continues to evolve even though some of the original team members have already graduated and moved on. The current team has just finished a new version of the omniwheel, which they have made available to other research groups. They are now working to improve Rezero’s robustness so that it can better manage obstacles in an everyday environment.

Key infos

Robot name: Rezero
Mechanical engineering: Simon Dössegger, Péter Fankhauser, Corsin Gwerder, Jonathan Hüssy, Jérôme Käser, Thomas Kammermann, Lukas Limacher, Michael Neunert
Electrical engineering: Samuel Schüller, Swen Wigert
Industrial design: Jessica Baumgartner, Tu-Van Giang, Claudio Maestretti
Project supervisor: Prof. Dr. Roland Siegwart, Director of the ASL at ETH Zurich
Websites: http://rezero.ethz.ch, TED Talk
Status: Ongoing research project

Photo credits: Rezero in Motion (first photo): Karl-Heinz Hug, Ringier AG; Rezero in the Studio (third photo): Gerhard Born, Ringier AG.

Note: This post is part of our Swiss Robots Series. If you’d like to submit a robot to this series, or to a series for another country, please get in touch at info[@]robohub.org.

Manual programming of robots only gets you so far. And, as you can see in the video, for quadrocopters that’s not very far at all (see the “Without Learning” part starting at 1:30):

On its first try to navigate the obstacle course, the flying robot attempts to navigate based on a pre-computed flight path. The path is derived using a basic mathematical (“first principles”) model. But quadrocopters have complex aerodynamics – the force produced by the propellers changes depending on the vehicle’s velocity and orientation, and thus the actual amount of force produced is quite different from what the simple math describes.

What’s worse, these flying vehicles use soft propellers for safety, which bend differently depending on how much thrust is applied and wear rapidly with use (and even more rapidly when crashing).

Even with continuous feedback on the robot’s position from the motion capture system, manually programming the robots with a control sequence that takes all these imperfections into account is impractical.

My colleague Angela Schoellig and the Flying Machine Arena team here at ETH Zurich have now developed and implemented algorithms that allow their flying robots to race through an obstacle parcours – and learn to improve their performance.

Here is how Angela described the process to me:

The learning algorithm is applied to a quadrocopter that is guided by an underlying trajectory-following controller. The result of the learning is an adapted input trajectory in terms of desired positions. The algorithm has been equipped with several unique features that are particularly important when pushing vehicles to the limits of their dynamic capabilities and when applying the learning algorithm to increasingly complex systems:

1. We designed an input update rule that explicitly takes actuation and sensor limits into account by solving a constrained convex problem.
2. We developed an identification routine that extracts the model data required by the learning algorithm from a numerical simulation of the vehicle dynamics. That is, the algorithm is applicable to systems for which an analytical model is difficult (or impossible) to derive.
3. We combined model data and experimental data, traditional filtering methods and state-of-the- art optimization techniques to achieve an effective and computationally efficient learning strategy that achieves convergence in less than ten iterations.

The result is a robot that learns and improves each time it tries to perform a task.

In this example the robot races through a pylon parcours, calling to mind air races, such as the Red Bull Air Racing Championships or the Reno Air Races – except that there are no human pilots that spent their life learning to fly – here it’s robots doing the learning. And they are efficient, taking less than 10 training sessions to find the optimal steering commands!

Moreover, the learning algorithms are not specific to slalom racing, they can be used to learn other tasks. As Angela points out:

Our goal is to enable autonomous systems – such as the quadrocopter in the video – to ‘learn’ the way humans do: through practice.

The videos below show how learning algorithms can be used for other robotic tasks:

Full disclosure: Angela and the Flying Machine Arena team work in the same lab as I. Also, I’m working on RoboEarth, trying to allow robot learning on a much larger scale.

Link to audio file (20:20)

In this episode we talk to Dario Floreano, director of the Swiss National Center of Competence for Research (NCCR) in Robotics that gathers leading experts in the field working at Swiss institutions.

Dario Floreano

Dario Floreano is the director of the Swiss NCCR Robotics which gathers leading robotic experts in Switzerland from EPFL (home institution), ETH Zurich, University of Zurich and Dalle Molle Institute for Artificial Intelligence. The center was launched in December 2010 and will run for up to twelve years.

The center aims to develop human­-oriented robots that assist people in their daily lives and improve their quality of life. Examples include “care robots”, “neuroprosthetic”, “exoprosthetic”, “educational robots” and “environmental robots”. Their research is currently organized into 5 projects that they hope will result in new design principles, approaches, and technologies required for the conception and design of human-oriented robots, the materials and components they are made of, and the control methods that enable them to interface and operate with humans:

Project 1: Bio-mimetic sensing, actuation, and mobility
Project 2: Interaction and Manipulation
Project 3: Prosthetic Robotics
Project 4: Distributed Robotics
Project 5: Robots for Daily Life

Floreano tells us about the role of Swiss robotics in the world, how to manage a large research center, the importance of education, and their cross-disciplinary and translational work.

Finally, he shares the latest developments from his Laboratory of Intelligent Systems at EPFL, including flying robots that physically interact with their environment (see video below) and soft “cells” that can assemble in air.

Links:

• Download mp3 (13.1MB)
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• Swiss NCCR Robotics Homepage
• Laboratory of Intelligent Systems Homepage