Onboard quadrocopter failsafe: flight after actuator failure

Researchers demonstrate an onboard algorithm that allows a quadcopter to maintain stable flight and control after a complete motor failure.

Onboard quadrocopter failsafe -- Institute for Dynamic Systems and Control (IDSC), ETH Zurich, Switzerland - idsc.ethz.ch/ We have developed an algorithm allowing a quadrocopter to maintain stable flight despite the complete loss of a motor/propeller. In a previous video (youtu.be/bsHryqnvyYA) we have shown this algorithm in use, where a motion capture system was used to measure the position and orientation of the quadrocopter. In this video we have a pilot fly the quadrocopter. The algorithm is executed on the quadrocopter's onboard micro-controller, and the only sensors required are the quadrocopter's angular rate gyroscopes. We use blinking LEDs, mounted on the quadrocopter's arms, to indicate a virtual yaw angle, so that the pilot can control the vehicle with the same remote control commands after the failure. As an alternative to the LED system, an onboard magnetometer could be used to track the vehicle's yaw angle. Alternatively, using more sophisticated algorithms, the system could be made to work using only the rate gyroscopes. The failsafe controller uses only hardware that is readily available on a standard quadrocopter, and could thus be implemented as an algorithmic-only upgrade to existing systems. Until now, the only way a multicopter could survive the loss of a propeller or motor is by having redundancy (e.g. hexacopters, octocopters). However, this redundancy comes at the cost of additional structural weight, reducing the vehicle's useful payload. Using this technology, (more efficient) quadrocopters can be used in safety critical applications, because they still have the ability to gracefully recover from a motor/propeller failure. This technology is patent pending, and we hope that it will soon be available as a product on most commercial platforms. For more information, please see www.FlyingMachineArena.org. Researchers: Mark W. Mueller, Simon Berger, and Raffaello D'Andrea Pilot: Thomas Kägi Video: Mark W. Mueller, Markus Waibel, and Raffaello D'Andrea Location: Flying Machine Arena at ETH Zurich; and Zürichberg, Zürich Acknowledgements: This work is supported by and builds upon prior contributions by numerous collaborators in the Flying Machine Arena project. See flyingmachinearena.org/people. This work was supported by the SNSF (Swiss National Science Foundation).