{"action":"created","issue":{"url":"https://api.github.com/repos/PX4/Firmware/issues/6856","repository_url":"https://api.github.com/repos/PX4/Firmware","labels_url":"https://api.github.com/repos/PX4/Firmware/issues/6856/labels{/name}","comments_url":"https://api.github.com/repos/PX4/Firmware/issues/6856/comments","events_url":"https://api.github.com/repos/PX4/Firmware/issues/6856/events","html_url":"https://github.com/PX4/Firmware/issues/6856","id":215285062,"number":6856,"title":"VTOL Standard transition improvements","user":{"login":"dagar","id":84712,"avatar_url":"https://avatars0.githubusercontent.com/u/84712?v=3","gravatar_id":"","url":"https://api.github.com/users/dagar","html_url":"https://github.com/dagar","followers_url":"https://api.github.com/users/dagar/followers","following_url":"https://api.github.com/users/dagar/following{/other_user}","gists_url":"https://api.github.com/users/dagar/gists{/gist_id}","starred_url":"https://api.github.com/users/dagar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dagar/subscriptions","organizations_url":"https://api.github.com/users/dagar/orgs","repos_url":"https://api.github.com/users/dagar/repos","events_url":"https://api.github.com/users/dagar/events{/privacy}","received_events_url":"https://api.github.com/users/dagar/received_events","type":"User","site_admin":false},"labels":[{"id":10884840,"url":"https://api.github.com/repos/PX4/Firmware/labels/enhancement","name":"enhancement","color":"84b6eb","default":true},{"id":249514594,"url":"https://api.github.com/repos/PX4/Firmware/labels/vtol","name":"vtol","color":"bfe5bf","default":false}],"state":"open","locked":false,"assignee":{"login":"dagar","id":84712,"avatar_url":"https://avatars0.githubusercontent.com/u/84712?v=3","gravatar_id":"","url":"https://api.github.com/users/dagar","html_url":"https://github.com/dagar","followers_url":"https://api.github.com/users/dagar/followers","following_url":"https://api.github.com/users/dagar/following{/other_user}","gists_url":"https://api.github.com/users/dagar/gists{/gist_id}","starred_url":"https://api.github.com/users/dagar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dagar/subscriptions","organizations_url":"https://api.github.com/users/dagar/orgs","repos_url":"https://api.github.com/users/dagar/repos","events_url":"https://api.github.com/users/dagar/events{/privacy}","received_events_url":"https://api.github.com/users/dagar/received_events","type":"User","site_admin":false},"assignees":[{"login":"dagar","id":84712,"avatar_url":"https://avatars0.githubusercontent.com/u/84712?v=3","gravatar_id":"","url":"https://api.github.com/users/dagar","html_url":"https://github.com/dagar","followers_url":"https://api.github.com/users/dagar/followers","following_url":"https://api.github.com/users/dagar/following{/other_user}","gists_url":"https://api.github.com/users/dagar/gists{/gist_id}","starred_url":"https://api.github.com/users/dagar/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/dagar/subscriptions","organizations_url":"https://api.github.com/users/dagar/orgs","repos_url":"https://api.github.com/users/dagar/repos","events_url":"https://api.github.com/users/dagar/events{/privacy}","received_events_url":"https://api.github.com/users/dagar/received_events","type":"User","site_admin":false},{"login":"sanderux","id":14801663,"avatar_url":"https://avatars3.githubusercontent.com/u/14801663?v=3","gravatar_id":"","url":"https://api.github.com/users/sanderux","html_url":"https://github.com/sanderux","followers_url":"https://api.github.com/users/sanderux/followers","following_url":"https://api.github.com/users/sanderux/following{/other_user}","gists_url":"https://api.github.com/users/sanderux/gists{/gist_id}","starred_url":"https://api.github.com/users/sanderux/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/sanderux/subscriptions","organizations_url":"https://api.github.com/users/sanderux/orgs","repos_url":"https://api.github.com/users/sanderux/repos","events_url":"https://api.github.com/users/sanderux/events{/privacy}","received_events_url":"https://api.github.com/users/sanderux/received_events","type":"User","site_admin":false}],"milestone":null,"comments":6,"created_at":"2017-03-19T18:47:54Z","updated_at":"2017-03-22T15:16:00Z","closed_at":null,"body":"**Transition to FW**\r\n - FW actuators 100% immediately (integrators reset at start)\r\n - MC actuators 100% and will ramp down automatically as vehicle produces lift and MC thrust is no longer needed to hold altitude. Require MC thrust setpoint to drop below a parameterized threshold before considering forward transition successful.\r\n - use roll and yaw setpoints from FW position controller?\r\n\r\n**Transition to MC**\r\n - FW actuators ramp down proportionally to transition progress (airspeed or time)\r\n - MC actuators ramp up to 100% sooner (over 1-2 seconds?)\r\n - monitor ground speed and consider transition complete if ground speed <= max MC speed\r\n - check MPC initialization. Shouldn't be trying to abruptly stop immediately.\r\n\r\n**Ideas for future improvement**\r\n - We need position control at all times. With any airspeed L1 navigation is more appropriate for a standard VTOL.\r\n - Multicopter with pusher should be allowed to achieve speeds much closer to FW minimum airspeed. This bridges the gap during transitions.\r\n - Transition to FW start using FW position controller sooner, but prevent TECS from pitching down\r\n    - use MC position controller (with appropriate VT_DWN_PITCH_MAX) to first accelerate vehicle to an appropriate level that FW position (and TECS) can takeover. TECS can have control of the throttle, but not allowed to pitch down.\r\n - Transition to MC\r\n   - Two phase transition\r\n   - Phase 1: FW position control with throttle cut to brake (forced to hold altitude) once speed decreases to acceptable level for MC position controller move on to phase 2. MC actuators are blended in to be at 100% for phase 2. Flaps could also be deployed for braking.\r\n   - Phase 2: MC position controller initialized with current velocity and given full control for reasonable braking"},"comment":{"url":"https://api.github.com/repos/PX4/Firmware/issues/comments/288431391","html_url":"https://github.com/PX4/Firmware/issues/6856#issuecomment-288431391","issue_url":"https://api.github.com/repos/PX4/Firmware/issues/6856","id":288431391,"user":{"login":"tubeme","id":12617619,"avatar_url":"https://avatars2.githubusercontent.com/u/12617619?v=3","gravatar_id":"","url":"https://api.github.com/users/tubeme","html_url":"https://github.com/tubeme","followers_url":"https://api.github.com/users/tubeme/followers","following_url":"https://api.github.com/users/tubeme/following{/other_user}","gists_url":"https://api.github.com/users/tubeme/gists{/gist_id}","starred_url":"https://api.github.com/users/tubeme/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/tubeme/subscriptions","organizations_url":"https://api.github.com/users/tubeme/orgs","repos_url":"https://api.github.com/users/tubeme/repos","events_url":"https://api.github.com/users/tubeme/events{/privacy}","received_events_url":"https://api.github.com/users/tubeme/received_events","type":"User","site_admin":false},"created_at":"2017-03-22T15:16:00Z","updated_at":"2017-03-22T15:16:00Z","body":"> Below min airspeed TECS will want to pitch down, which we can't allow during forward transition.\r\n\r\nWe've had a lot of this cases in the past... I understand now.\r\n\r\nThanks @sanderux and @dagar "}}
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