Mark Mueller
4 HN mentions · mentioned in 4 months, 2014–2019
1:00 · 219K views · Dec 2, 2013
An ETH Zurich lab demonstration of a failsafe algorithm that lets a quadrocopter detect the loss of a propeller and recover, returning to its original position.
HN cites it to show that a quadcopter can keep flying after losing a rotor, though under ideal lab conditions.
4 comments from Hacker News
I wonder if the algorithm could be applied to flying robots or other flying vehicles? If there was sufficient height maybe? It reminds me of this quadcopter drone recovering from the loss of 1 rotor, this video Although the drone in that video uses a pre-computed strategy, I think, not a general experiment and learning approach. And it recovers by spinning around on its axis, which saves the drone, and the environment, from further damage, but makes the damaged drone useless for most applications.
The Ehang 184 has 8 propellers, two for each of the four quad points. I'd assume the reason is safety, that it can limp to the ground with just 7. You're wrong about a quadcopter not being able to fly with 3 rotors, see this video: this video That looks like it would be quite a ride with a human on-board, but would probably suck less than crashing.
Aha! I couldn't find the video quickly for my first post but I finally stumbled on it. Granted this is in ideal laboratory conditions but: this video
I recall a quadcopter control mode that spins the entire craft quite rapidly, exchanging yaw control for altitude control. Found a vid: this video