{"action":"created","issue":{"url":"https://api.github.com/repos/diydrones/ardupilot/issues/1971","labels_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1971/labels{/name}","comments_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1971/comments","events_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1971/events","html_url":"https://github.com/diydrones/ardupilot/issues/1971","id":60798856,"number":1971,"title":"APM:Copter: fence action, what might happen","user":{"login":"robustini","id":3864712,"avatar_url":"https://avatars.githubusercontent.com/u/3864712?v=3","gravatar_id":"","url":"https://api.github.com/users/robustini","html_url":"https://github.com/robustini","followers_url":"https://api.github.com/users/robustini/followers","following_url":"https://api.github.com/users/robustini/following{/other_user}","gists_url":"https://api.github.com/users/robustini/gists{/gist_id}","starred_url":"https://api.github.com/users/robustini/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/robustini/subscriptions","organizations_url":"https://api.github.com/users/robustini/orgs","repos_url":"https://api.github.com/users/robustini/repos","events_url":"https://api.github.com/users/robustini/events{/privacy}","received_events_url":"https://api.github.com/users/robustini/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/diydrones/ardupilot/labels/ArduCopter","name":"ArduCopter","color":"02e10c"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":3,"created_at":"2015-03-12T10:34:06Z","updated_at":"2015-03-13T02:46:47Z","closed_at":null,"body":"With an heavy \"X8\" (coax, 17\" props) we had an unpleasant event.\r\nDuring a \"fence\" event, at the speed of 14 m/s, the quad is literally bounced, resulting crash.\r\nAnalyzing the log we noticed excessive current consumption and an unexpected voltage drop, we are analyzing the hardware to understand if something is undersized, but apart from that the quad is almost bounced, and imho this is not correct.\r\nRegardless this issues I believe that the \"fence\" is not operating properly, rather than engage immediately RTL, then force the quad has to fly in the opposite direction during the event , it would be correct that first should reach in Loiter for a few seconds (3 or 5, are enough) then later if the pilot does not engage in any action should automatically switch to RTL, to prevent an over overcompensation.\r\nThe initial effect that you should have during fence action should be identical to the achievement of a common waypoint with a loiter action.\r\nThe video of this event:\r\n\r\nhttps://www.dropbox.com/s/nsqi2hj6938103h/crash%2Bslomo.mov?dl=0\r\n\r\nAnd here the log:\r\n\r\nhttps://drive.google.com/file/d/0B3HEcrNCOga9blprUHRCMWFwcWc/view?usp=sharing\r\n\r\nSo for a future version of fence I propose an additional option, \"Loiter, then RTL\"."},"comment":{"url":"https://api.github.com/repos/diydrones/ardupilot/issues/comments/78762269","html_url":"https://github.com/diydrones/ardupilot/issues/1971#issuecomment-78762269","issue_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1971","id":78762269,"user":{"login":"rmackay9","id":1498098,"avatar_url":"https://avatars.githubusercontent.com/u/1498098?v=3","gravatar_id":"","url":"https://api.github.com/users/rmackay9","html_url":"https://github.com/rmackay9","followers_url":"https://api.github.com/users/rmackay9/followers","following_url":"https://api.github.com/users/rmackay9/following{/other_user}","gists_url":"https://api.github.com/users/rmackay9/gists{/gist_id}","starred_url":"https://api.github.com/users/rmackay9/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/rmackay9/subscriptions","organizations_url":"https://api.github.com/users/rmackay9/orgs","repos_url":"https://api.github.com/users/rmackay9/repos","events_url":"https://api.github.com/users/rmackay9/events{/privacy}","received_events_url":"https://api.github.com/users/rmackay9/received_events","type":"User","site_admin":false},"created_at":"2015-03-13T02:46:47Z","updated_at":"2015-03-13T02:46:47Z","body":"I've looked at the logs provided by Marco and done some tests in AC3.2.1 and master and it looks like we could do a better job of gently slowing the copter when entering RTL.\r\nThe first graph shows what happens in AC3.2.1 when entering RTL at high-speed.  Although better than AC3.1.5 it still slows down too rapidly and then pitches forward again.  In the actual log, the vehicle was travelling at a similar speed (14m/s in the actual logs, 18m/s in simulator)\r\n![ac321_enteringrtl](https://cloud.githubusercontent.com/assets/1498098/6632261/818c2f56-c976-11e4-9a8c-bab1d4b9ff52.png)\r\n\r\nThe picture is worse in master in which we have a nasty spike when first entering RTL.\r\n![master_twitchenteringrtl](https://cloud.githubusercontent.com/assets/1498098/6632255/562cae94-c976-11e4-84d4-0c873e56e490.png)\r\n\r\nI'm going to title this issue."}}