Robohub.org
 

Fully autonomous flapping-wing micro air vehicle weighs about as much as 4 sheets of A4 paper


by
16 December 2013



share this:
DelFlyExplorerInFlight
The DelFly Explorer, a flapping wing MAV equipped with a 4-gram stereo vision system that can fly completely by itself in unknown, cluttered environments. © Delft University of Technology.

The DelFly Explorer is the first flapping wing Micro Air Vehicle (MAV) that is able to fly with complete autonomy in unknown environments. Weighing just 20 grams and with a wingspan of 28cm, it is equipped with an onboard stereo vision system. The DelFly Explorer can perform an autonomous take-off, keep its height, and avoid obstacles for as long as its battery lasts (~9 minutes). All sensing and processing is performed on board, so no human or offboard computer is in the loop.

Inspired by flying animals, flapping-wing MAVs are highly manoeuvrable, able to quickly transition between multiple flight regimes (such as between hover and forward flying), and are robust to collisions. Their low weight and unobtrusive appearance, as well their ability to fly at low speeds and operate quietly, make them more suitable for use indoors or in the presence of humans than many other aerial platforms. There are many future applications, such as the detection of ripe fruit in green houses, for which flapping wing MAVs would need to fly without human intervention.

However, designing flapping-wing MAVs that are capable of autonomous flight is challenging, because of their small scale and extremely limited payload capabilities. Therefore, previous work in this area either focused on sub-tasks (such as led-following) or out-sourced parts of the sensing and control to external cameras and/or computers.

We achieved the fully autonomous flight of the DelFly Explorer by resolving the following four main challenges:

  1. Onboard sensing/processing: We have developed a 4-gram onboard stereo vision system (2 cameras + processor) and 1-gram onboard autopilot with processor, barometer, accelerometers and gyros.
  2. Vision algorithms: We developed a new approach to purposive vision, in which the vision algorithms make use of sub-sampling and extract only as many image samples as necessary for subsequent control. As a result, all vision algorithms run at frame rate. Specifically, we designed efficient vision algorithms that can cope with the absence of visual texture, as often happens in indoor environments (see the empty walls in the lecture room as an example). The algorithms also deal with the distortions that are introduced by the combination of the flapping motion and the rolling shutter cameras.
  3. Control algorithms: We devised a control algorithm that ensures obstacle-free flight by construction. It takes into account the fact that the DelFly Explorer cannot hover in place by always ensuring an obstacle-free region in which the DelFly can turn around. The height control is based on the onboard barometer.
  4. Payload capability: Compared to its predecessor (the 16-gram, 28cm wingspan flapping-wing DelFly II), the Explorer’s payload capability was increased enough to carry the stereo vision system and autopilot. This was achieved both by a redesign of the wings and by a reduction in the number of coils in the brushless motors.

We have performed experiments in various indoor spaces, ranging from lecture rooms to office rooms and lab spaces. Below, you see a part of an autonomous flight in a lecture room at TU Delft. The image has been made by retaining the motion regions every 10 frames in the experimental video. The original experimental video can be seen here.

DelFly_Collage
A small part of the DelFly Explorer’s trajectory during a 9-minute autonomous flight. It runs efficient vision and control algorithms on board in order to avoid obstacles in the environment. © Delft University of Technology.

The current algorithms allow collision-free flight, but do not yet form a complete solution to autonomous exploration. We are working to extend the DelFly’s exploration capabilities so that it can pass through open doors or windows, which it currently avoids.

For more information and videos, please visit the DelFly website.

Reference

“Autonomous Flight of a 20-gram Flapping Wing MAV with a 4-gram Onboard Stereo Vision System”, by C. De Wagter, S. Tijmons, B.D.W. Remes, and G.C.H.E. de Croon, (submitted).

Team

Christophe De Wagter
Sjoerd Tijmons
Bart Remes
Guido de Croon

Contact

g.c.h.e.decroon@tudelft.nl

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

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



tags: , , , , , ,


Guido de Croon is Full Professor at the Micro Air Vehicle lab of Delft University of Technology in the Netherlands.
Guido de Croon is Full Professor at the Micro Air Vehicle lab of Delft University of Technology in the Netherlands.





Related posts :



Robot Talk Episode 126 – Why are we building humanoid robots?

  20 Jun 2025
In this special live recording at Imperial College London, Claire chatted to Ben Russell, Maryam Banitalebi Dehkordi, and Petar Kormushev about humanoid robotics.

Gearing up for RoboCupJunior: Interview with Ana Patrícia Magalhães

and   18 Jun 2025
We hear from the organiser of RoboCupJunior 2025 and find out how the preparations are going for the event.

Robot Talk Episode 125 – Chatting with robots, with Gabriel Skantze

  13 Jun 2025
In the latest episode of the Robot Talk podcast, Claire chatted to Gabriel Skantze from KTH Royal Institute of Technology about having natural face-to-face conversations with robots.

Preparing for kick-off at RoboCup2025: an interview with General Chair Marco Simões

and   12 Jun 2025
We caught up with Marco to find out what exciting events are in store at this year's RoboCup.

Interview with Amar Halilovic: Explainable AI for robotics

  10 Jun 2025
Find out about Amar's research investigating the generation of explanations for robot actions.

Robot Talk Episode 124 – Robots in the performing arts, with Amy LaViers

  06 Jun 2025
In the latest episode of the Robot Talk podcast, Claire chatted to Amy LaViers from the Robotics, Automation, and Dance Lab about the creative relationship between humans and machines.

Robot Talk Episode 123 – Standardising robot programming, with Nick Thompson

  30 May 2025
In the latest episode of the Robot Talk podcast, Claire chatted to Nick Thompson from BOW about software that makes robots easier to program.

Congratulations to the #AAMAS2025 best paper, best demo, and distinguished dissertation award winners

  29 May 2025
Find out who won the awards presented at the International Conference on Autonomous Agents and Multiagent Systems last week.



 

Robohub is supported by:




Would you like to learn how to tell impactful stories about your robot or AI system?


scicomm
training the next generation of science communicators in robotics & AI


©2025.05 - Association for the Understanding of Artificial Intelligence


 












©2025.05 - Association for the Understanding of Artificial Intelligence