{"action":"opened","issue":{"url":"https://api.github.com/repos/cleanflight/cleanflight/issues/887","labels_url":"https://api.github.com/repos/cleanflight/cleanflight/issues/887/labels{/name}","comments_url":"https://api.github.com/repos/cleanflight/cleanflight/issues/887/comments","events_url":"https://api.github.com/repos/cleanflight/cleanflight/issues/887/events","html_url":"https://github.com/cleanflight/cleanflight/issues/887","id":75719879,"number":887,"title":"Implement ETH Zurich safety algorithm","user":{"login":"alexgorbatchev","id":65633,"avatar_url":"https://avatars.githubusercontent.com/u/65633?v=3","gravatar_id":"","url":"https://api.github.com/users/alexgorbatchev","html_url":"https://github.com/alexgorbatchev","followers_url":"https://api.github.com/users/alexgorbatchev/followers","following_url":"https://api.github.com/users/alexgorbatchev/following{/other_user}","gists_url":"https://api.github.com/users/alexgorbatchev/gists{/gist_id}","starred_url":"https://api.github.com/users/alexgorbatchev/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/alexgorbatchev/subscriptions","organizations_url":"https://api.github.com/users/alexgorbatchev/orgs","repos_url":"https://api.github.com/users/alexgorbatchev/repos","events_url":"https://api.github.com/users/alexgorbatchev/events{/privacy}","received_events_url":"https://api.github.com/users/alexgorbatchev/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-05-12T19:59:13Z","updated_at":"2015-05-12T19:59:13Z","closed_at":null,"body":"Search didn't show this was suggested earlier. I believe it would be great for Cleanflight and community overall to have this implemented. Perhaps a small Kickstarter campaign to sponsor this feature?\r\n\r\n> — This paper presents periodic solutions for a\r\nquadrocopter maintaining a height around a position in space\r\ndespite having lost a single, two opposing, or three propellers.\r\nIn each case the control strategy consists of the quadrocopter\r\nspinning about a primary axis, fixed with respect to the vehicle,\r\nand tilting this axis for translational control. A linear, timeinvariant\r\ndescription of deviations from the attitude equilibrium\r\nis derived, allowing for a convenient cascaded control design.\r\nThe results for the cases of losing one and two propellers\r\nare validated in experiment, while the case of losing three\r\npropellers is validated in a nonlinear simulation. These results\r\nhave application in multicopter fault-tolerant control design,\r\nand also point to possible design directions for novel flying\r\nvehicles.\r\n\r\nReferences:\r\n\r\n* [New algorithm makes quadrocopters safer](https://www.ethz.ch/en/news-and-events/eth-news/news/2013/12/new-algorithm-makes-quadrocopters-safer.html)\r\n* [White paper](http://flyingmachinearena.org/wp-content/publications/2014/mueIEEE14.pdf)\r\n\r\nhttps://www.youtube.com/watch?v=bsHryqnvyYA\r\n\r\n "}}