Source: Franka.de

The robotic industry is currently surfing on a new wave of collaborative robots. With several big companies trying to make their way into the market, there is still a huge effort from emergent companies to get a piece of the market. This new German collaborative robot is continuing this wave of small companies emerging with some awesome concepts. 

Here’s Franka.

With one of the most fast growing robotic economy in the world and a huge emphasis on safety, this is not a surprise to see a German company launching a new cobot. In fact, Germans are still refusing to use some of the collaborative robots on the market because of safety concerns. With the new ISO/TS 15066 out, I guess it was time for a German company to launch a robot that seems to operate within the guidelines of the technical specification.

What’s under the HOOD?

We don’t have a lot of details on the use of this robot, but we do have information on its specifications.

Source: franka.de

The 7-axis Franka has a 3kg payload and a 800mm reach. The robot has a +/-0.1mm repeatability and has force torque sensors in every single joint. It has a 60mm stroke parallel gripper with limited force (140N) that fits perfectly with the new ISO/TS 15066. The gripper also has 3D printed interchangeable fingers. The user interface is a web browser that seems to be really intuitive for programming. With some icons here and there, you can teach a couple of waypoints and there you go, your robot is running. The robot’s weight is only 18.5kg, which makes it easy to place pretty much anywhere you can think of.

At 9,900 Euros (+/- 12,000 USD), this robot is totally shocking the robotic industry. In fact, with many functionalities and a very low price, it can certainly mix things up during a customer’s search for an easy to use and cheap solution.

This robot makes me think of the Gomtec Roberta (bought by ABB in 2015). The same mentality seems to drive the design of this robot. A simple and easy to use robot with embedded sensors and a gripper of high quality, which makes human robot interaction very safe.

Automatica

It is very refreshing to see this type of a robot out there. It’s been a while (since IREX actually) that anyone has announced a new collaborative robot. With the upcoming Automatica, I am sure that some companies will be showcasing new robots and hopefully we will see many of the previous robots, which were still prototypes getting out on the market.

I am also looking forward to see robots that will have ISO/TS 15066 oriented specification or modifications. This will be an interesting summer for collaborative robots.

Source: Smart & Digital Factory Application Lab van Sirris in Kortrijk

We often see robotic or automated cells purposed to do a single motion or a very specific application. However, with all the new technology available in the market, it is interesting to see how each separate technology can be integrated into a single versatile cell. This is what Sirris did and it is quite impressive.  

Sirris is a collective center for the technology industry in Belgium and has more than 8 sites throughout the country. Their goal is to help companies keep up with the evolution of technology, particularly with regards to automation. In fact, with a huge team of engineers, technicians and scientists, Sirris is using its laboratories, innovation centers and show rooms to develop, test and demonstrate the different applications they help develop for specific customers.

Lately they have been promoting their new (8th) location by showcasing an example of what an Industry 4.0 robotic cell might look like. This cell uses a bunch of new technology and it’s very impressive. The proposed cell highlights some of the concerns manufacturers have been having over the past 2-3 years about where automation was going next. I think we have our answer here! See the video below to learn more.

The cell

The automation process is divided into three major cells. Let’s find out what they are meant for:

• Ordered Picking: Using smart glasses and a smart watch, the user can pick (and place) the required parts in a bin. Using these devices allows the operator to verify if the right number of parts are preloaded in the tray, that the assembly line has the right number of parts during the assembly process and to do this verification of inventory in real time.
• Transition No. 1: As the tray is set on a mobile robot or AGV (automated guided vehicle), the operator simply signals that the tray has been loaded and that the robot can move to the next step in the process. Through different guiding sensors, the mobile robot can make its way to the next cell (imagine the other cell could be on the other side of the plant) and be ready for the next step.
• Assembly Cell: As the trays are filed with parts, the operator and the collaborative robots are building the assembly together. In fact, since the robot is really good at pick and place and the human is very good at manipulation, they split tasks to make the job easier and faster. Once the part is assembled, the robot places the tray on the mobile robot. It can then go to the quality testing station. Notice that the robot used is a KUKA LBR iiwa with a Robotiq 2-Finger 140 Adaptive Gripper. You also see a Universal Robots UR3 used to screw different components together.
• Transition No. 2: Once again, the final step is getting to the last quality check. Notice that sensors are used to navigate within the room and that mechanical devices are installed on both the mobile robot and the table to make the mobile robot’s position repeatable.
• Quality Check: With the help of different types of technology (software and vision systems), the company can do the final quality check. This will confirm that the product meets the requirements established by the company.

For more pictures of the showroom, follow this link.

According to Sirris:

In this way, the new lab makes the cooperation and interaction between human operator and robots more tangible and feasible to the manufacturing industry. The focus on flexible automation of assembling makes specific technology applications available to machine building and mechatronics companies. After all,  to many companies automation and robotics in particular still seem way out of reach, too futuristic for their production. Until they see the possibilities “in real life”.

In fact with few examples of real life applications of complex automation, customers and even integrators sometimes have difficulty figuring out how they can automate certain processes. With technology reaching new levels at a fast rate, it is cool to see the final results of an automation cell, which might be complex for the integrator, but is totally transparent and easy to use for the end user.

This is truly an example of Industry 4.0 happening now.

Safety

For safety purposes you should set your payload. In fact, especially for collaborative robots where human-robot interaction is anticipated, it is important to determine what the reaction of the robot should be. Since the robot is able to feel an impact to its joints or at its base, it is normal to set the payload of each motion of the robot to tell it that it is carrying X weight and that it should be feeling Y force. If this force is exceeded, then this would be an abnormal force and could mean a problem.

For example, take a robot that is carrying a 5kg (49.05N) payload. The program has been set in order to tell the robot it has acquired this payload in its gripper. If under normal operating conditions the robot accidentally hits a human operator, then you would want the robot to react, preferably to slow down and stop. If the safety setting were set to 60N, this means the robot is very sensitive and will stop at +/-10N impact, which is pretty small.

To take full advantage of the robot programming, you should set the program when the robot isn’t carrying a specific payload. The safety setting will consequently be adjusted.

Acceleration

The same principle applies for acceleration. Since the robot has been set to a certain acceleration and that acceleration is done by powering the robot joints, the robot needs to know the payload carried. In fact, if the acceleration has to be fast and the payload is at its max, the motor will in all likelihood read an overcurrent and call an emergency stop.

The opposite is also true: if you have no payload, but the robot thinks it has a certain payload, it will read an undercurrent. This will lead the robot to accelerate quite fast, which can produce a collision or a misalignment of the robot arm.

Don’t forget that the base payload has to include the robot tool. The full payload should consider the robot tool and the part it is carrying.

How to know if my payload is set correctly?

Since there are a couple of factors that can contribute to your robot payload, it may be hard to determine the exact payload to be set in the program. Luckily, there is a very easy way to test if your robot payload has been set correctly.

Since we did some of our testing with Universal Robots I will use this specific situation, but most robots will follow the same rules.

You will set the robot payload in your basic settings; with UR you can touch the button at the back of the teach pendant called: ”FREE DRIVE”. If the robot arm moves up, the payload is set too low or is too light. If the robot arm is going down, the payload is set to high or is too heavy. With this approach you can then fine tune your payload — just note the adjustment needed and adjust the payload setting in your UR program.

These are a couple of easy tricks that can save you a lot of trouble when debugging your robot. We will be posting more technical articles in the next few weeks and would like to have your feedback and your input on problems you have experienced (in this case) with your robot payload.

Force sensing can be achieved by using the embedded force sensors in most of the collaborative robots models that are on the market today. I have used the built-in force feedback loops on Universal Robots and was able to get it to do what I wanted. The only downside of using an embedded force sensor is that you don’t have the same accuracy as a device that is dedicated to reading forces. Most built-in force sensors will be reading the robot current, but will not register overcurrent. And some force sensors will use other strategies such as material deformation to determine the force applied on the tool.

Robotiq has run preliminary tests on some robot models and we have found that embedded force sensors will have a +/- 5-10 N of sensitivity depending on the robot orientation/configuration. In the case of a dedicated sensor like the FT 150, the sensitivity is down to +/- 0.5 N.

1. Constant Force

Force-torque sensors were first manufactured for applications like grinding, polishing and other material removal applications. Since these applications are hard to automate in terms of position, the robot needs some kind of force feedback indication to know if it is pushing too hard on the part or if it is barely touching it.

By introducing a force feedback loop into your programming you can easily automate these applications and have a consistent result in your manufacturing process. In this situation you will need to use an external device instead of the embedded solution provided by the robot manufacturer.

2. Object Location

We are in touch with customers constantly and they usually think that the only way to locate or quantify a part is by using vision sensors. But this isn’t the only solution. It is true that vision systems are a good way to locate or quantify parts, but it is also possible to seek and detect parts with force sensing. Locating them along the X-Y plane is one thing, but determining the height that they are located at is another. In fact, doing so with vision requires a 3D vision system. In the case of a pile of objects, you don’t necessarily have to keep count of objects in the pile, you just need to seek the pile each and every time. As demonstrated in the following video, the robot will determine the height of the pile and will consequently adjust its grasping height.

Another way to use a force sensor’s seeking capabilities is for the sensor to be in ”free mode”. This is probably the most underestimated, undervalued and underused parameter of any FT sensor. The ”free mode” or ”zero gravity” mode will allow you to ”liberate” axes on your robot, and this will allow it to increase its compliance. For example, if you would like to tighten a part in a CNC machine chuck, you could liberate 2 axes to allow the part to align perfectly in the chuck, while still maintaining a grip on the part in the air. This will allow the chuck to center your part and will not place extra force on your robot axes.

3. Repeatable Force

If you are thinking about using a robot to do assembly tasks, you want your robot to be able to repeat the same task again and again. However, one of the reasons why assembly tasks are hard to automate is that they require force sensing by the operator. By introducing an FT sensor, you can feel the external force applied during the assembly process.

If you take a look at the following video, you will see that it is crucial to apply the exact same (tiny bit of) force on the battery and on the cell phone cover. Since those parts are fragile it is really tricky to assemble them together without crushing everything. This is why a low force threshold is set to prevent a misalignment of and damage to the parts.

4. Weighing Stuff

As seen in the video above (Section 2: Object Location), the application will differentiate the orange from the blue hockey pucks. However, the way to do it has nothing to do with their color. In fact, it is done by their weight. The orange pucks are heavier than the blue ones, and the sensor is able to differentiate the weight of each puck and order them according.

This could be used to distinguish between similar but different parts. However, in real life, what is most helpful is knowing if you have the right object in your gripper or if you have lost or dropped an object, as this can really help you in your manufacturing process. A force torque sensor can easily determine this.

5. Hand Guiding

Most collaborative robots out there will use their embedded FT sensors to achieve hand guiding, yet some of the industrial robot models don’t even have this type of sensor. This is why an FT sensor would be a useful addition to your robot arm. Also there is the fact that you will be able to teach your robot what you want it to do by demonstration. An FT sensor will allow you to teach your robot start and end points, as well as linear trajectories.

***

As you can see, force feedback is pretty useful and can be applied to a bunch of very diverse applications. Make sure to analyze your process and see if you can use force sensors instead of vision systems. Most of the time, force sensors are easier to integrate and do not require an integrator; you can probably add it yourself.

Every time we attend a meeting with robot newbies, they always have very slick ideas about what a robot should be able to do and how it will be done. The ideas are usually all really great and there is certainly a way to achieve them, however, it might take more time, energy and money with less return on investment than might be desirable. You have to be realistic too.

The bottom line is, robots are still pretty complex in general, but there are some applications that are easier than others. This is why we have split the image in our graphic into two sections with an easy and hard side. It is not that the hard side is impossible to do; it is just more complex and requires more effort.

Tasks

Robots are extremely accurate and repeatable in terms of position. It is easy even for a robot that is not very precise to repeat a position within 0.01 mm. So you don’t have to be worried about placing an object at the very same spot each and every time.

However, robots are still hard to automate when their environment is not very repeatable. For example, if an assembly requires hole localization using force feedback, or if you need to polish a part at a precise dimension. Having force feedback adds another level in terms of programming and is tougher to integrate into a first application. You may want to look for applications that can be done without using any input from workers, for example pick-and-place.

Parts

The choice of the part you will handle is critical in a robotic application. The more square or flat surfaces you have, the easier it is. The rigidity of the part will also make a huge difference. Handling the same part or the same family of parts is also a lot easier, because there will be fewer adjustments to make during production. Having a large range of part shapes and sizes will increase the complexity of the grasp.

Having the right kind of gripper can ease your robotic integration. Grippers like the Robotiq Adaptive Gripper are able to handle fragile or deformable objects and even different types of objects, but very few grippers can do this.

Part presentation

The way you present your parts to the robot is critical to the success of your robotic integration. Trays and fixed locations are the easiest to automate.

Bin picking, conveyors and other moving devices are harder to automate, since they require a superior level of intelligence, integration or sensors. This means you will need vision or encoders to determine the part position before grasping it.

Integration with other machines

Using your preexisting machine setup will remain your easiest option. In fact, when integrating a robot into a machine shop, the interface between the machine and the robot is always the hardest part. Robots don’t usually speak the same “language” as your other machines, which can make the connectivity quite complex. Remember that you should start small, with fewer devices to automate. For example, start by closing a door with the robot instead of introducing an automatic door with I/O’s.

Programming

Robots are good for redundant, boring things, but they are not yet good at decision making. This is why in your program you should reduce the level of logic required to the most basic sequence.

For more information on how to integrate your first robot in your workshop, you may want to take a look at the series: Getting Started with Collaborative Robots. This series will guide you through the different steps of integrating a collaborative robot in a workshop.

Anyone who has been in robotics long enough is eventually tasked with figuring out how many axes they will need for their robot. Most robots have somewhere between three and seven axes, but how do you determine how many you actually need? Here’s a recap of the different types of robots you are likely to encounter, classified by their number of axes (or degrees of freedom).

What is a robot axis?

An axis, in a robotics context, can be interpreted as a degree of freedom (DOF). If a robot has 3 degrees of freedom it can manoeuvre the X-Y-Z axes. However, it cannot tilt or turn. When you increase the number of axes (DOF) on a robot, you can access more space than with a robot that has a lower number of axes. Note that a robot is typically purchased with a given number of axes and it is nearly impossible to add supplementary axes after the fact.

One way to identify the number of DOF of a robot is to simply count its motors. This can be difficult, however, as the motors are often embedded within the robot’s casing. Just be aware that the more axes a robot has, the greater its manoeuvrability. If you need a robot to conduct a complex operation, you will most likely need a robot with greater flexibility.

In the list below we’ve put together handy descriptions of different types of robots, classified by their DOF. Notice there are lots of differences between robot types. Depending on the manufacturer, a robot type may have more, or fewer, axes. So please consider this information as a general guide.

3-axis

3-axis robots — also known as cartesian robots or scara robots — can be compared to a 3-axis CNC machine or a 3D printer. They are robots that allow tools to travel along their 3 axes, using 3 different motors. These robots can be used for simple pick-and-place operations, where parts will be placed in the same orientation and will be dropped in the exact same spot. For example: if the robot grabs a part in a given orientation, it will need to move in that same orientation because the tool cannot turn.

A crane is a good example of a 3-axis robot.

4-axis

If you have a 4-axis robot, you can turn the part around a fourth axis while still traveling along the X-Y-Z axes. Scara, delta and some traditional robots are considered 4-axis robots.

A 4-axis robot will have four different motors. Typically, the only difference with a cartesian robot is that the fourth axis will be used to rotate the tool. For example: a series of parts is presented on a conveyor and has to be grabbed by the robot. You will have to locate the position of the part (X-Y axes), go down to the height (Z- axis), and finally, tilt the tool to match the orientation of the part.

5-axis

This is where traditional robots begin to show up in our discussion. In fact, a lot of industrial robots have 5 axes. These robots can travel through the three spatial axes (X-Y-Z) and the tool can be turned around on two further axes. In other words, the tool can be turned around axis Z and around axis Y, but cannot be turned around axis X. This means it does not have total freedom of movement and there will still be some positions that cannot be achieved.

You can also imagine a 5-axis robot, similar to a 5-axis CNC machine, where your tool can travel through the X-Y-Z axes, the table can spin around the Z-axis (effectively making 4 axes), and finally the table can tilt around another axis (5-axis).

6-axis

At a minimum, a 6- axis robot is fully free: it can travel through X-Y-Z axes and turn around each axis. The difference between the 5-axis robot shown in the picture is that axes 4 and 5 can turn around another axis. A good example of a 6-axis robot would be the Universal Robot. You can easily count the 6 blue caps (which cover the motors) and easily identify which motor is doing what.

7-axis

We just said that 6-axis robots are free to reach every location available in space, so what is the point of having a 7-axis robot? Well, having that extra axis allows you to arrive at an end effector position with several joint configurations. It is used to avoid singularities and to be able to avoid certain objects by placing the arm in different orientations than what a 6-axis robot could accomplish. A great example of a 7-axis robot would be the Motoman SDA series. 7-axis robots are also called ‘redundant robots’ because they have one extra axis.

What about 12 and 13 axis robots?

This just means that two 6-axis robots are joined together to form a 2-armed robot. It may be that the base of this robot can rotate around itself; this will then add an axis (arriving at 13 axes). But in terms of space, these robots can’t reach any further with their 12 axes because there are only three dimensions in our perception.

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

• How to calculate a robot’s forward kinematics in 5 easy steps
• Where to place fuses and how to protect your robot and motors
• Dry vs wet, oil vs grease: Choosing the right lubrication for your robot
• Selecting a camera and lens for your robot
• Things to think about when transporting your robot

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