{"action":"created","issue":{"url":"https://api.github.com/repos/PX4/Firmware/issues/5072","repository_url":"https://api.github.com/repos/PX4/Firmware","labels_url":"https://api.github.com/repos/PX4/Firmware/issues/5072/labels{/name}","comments_url":"https://api.github.com/repos/PX4/Firmware/issues/5072/comments","events_url":"https://api.github.com/repos/PX4/Firmware/issues/5072/events","html_url":"https://github.com/PX4/Firmware/issues/5072","id":165812503,"number":5072,"title":"Unstable position hold using px4flow with pixhawk and QGC","user":{"login":"Graceson","id":20116292,"avatar_url":"https://avatars.githubusercontent.com/u/20116292?v=3","gravatar_id":"","url":"https://api.github.com/users/Graceson","html_url":"https://github.com/Graceson","followers_url":"https://api.github.com/users/Graceson/followers","following_url":"https://api.github.com/users/Graceson/following{/other_user}","gists_url":"https://api.github.com/users/Graceson/gists{/gist_id}","starred_url":"https://api.github.com/users/Graceson/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Graceson/subscriptions","organizations_url":"https://api.github.com/users/Graceson/orgs","repos_url":"https://api.github.com/users/Graceson/repos","events_url":"https://api.github.com/users/Graceson/events{/privacy}","received_events_url":"https://api.github.com/users/Graceson/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":7,"created_at":"2016-07-15T15:21:26Z","updated_at":"2016-07-20T14:23:38Z","closed_at":null,"body":"Hello everyone,\r\n\r\nI am having trouble to get a stable hovering using optical flow. I use a dji flamewheel F450 drone with pixhawk and QGC latest stable version. I don't have gps and I just use px4flow for position estimation. I have set the parameters to use the INAV position estimation method. When I switch to position control flight mode, the quad does a somewhat OK stable for 5 - 10 seconds, then it starts to drift. The altitude seems to be fairly constant, but the drifting is more in xy direction. Now when I try to get back to the position using the radio sticks (in position control mode itself) the quad goes really unstable and I have to switch it back to stabilize mode to regain control. I have tried the lpe position estimation mode also, but it is far more unstable than the INAV method. Is there any parameter change or setup that I can do to get more stable hovering using optical flow? I am happy since the quad is doing something when switched to position control (I took four weeks to get to this point). But I would like to get a better and reliable position hold. Since I am novice in this field, my apologies if my question is too basic. My project is a small part of a bigger research project, so I am in desperate need to get it working as soon as possible. Thanks in advance for everyone's help.\r\nAlso, below are the parameters than I changed to make the position control in INAV mode work: \r\n\r\n- SYS_MC_EST_GROUP -> position_estimator_inav, a Set multicopter estimator group\r\n\r\n- INAV_LIDAR_EST -> 1 (I dont use a lidar, but this parameter change was needed to make position               control work otherwise it would give me a reject position control even if the OF data was available)\r\n\r\nThanks again!\r\n"},"comment":{"url":"https://api.github.com/repos/PX4/Firmware/issues/comments/233964667","html_url":"https://github.com/PX4/Firmware/issues/5072#issuecomment-233964667","issue_url":"https://api.github.com/repos/PX4/Firmware/issues/5072","id":233964667,"user":{"login":"Graceson","id":20116292,"avatar_url":"https://avatars.githubusercontent.com/u/20116292?v=3","gravatar_id":"","url":"https://api.github.com/users/Graceson","html_url":"https://github.com/Graceson","followers_url":"https://api.github.com/users/Graceson/followers","following_url":"https://api.github.com/users/Graceson/following{/other_user}","gists_url":"https://api.github.com/users/Graceson/gists{/gist_id}","starred_url":"https://api.github.com/users/Graceson/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Graceson/subscriptions","organizations_url":"https://api.github.com/users/Graceson/orgs","repos_url":"https://api.github.com/users/Graceson/repos","events_url":"https://api.github.com/users/Graceson/events{/privacy}","received_events_url":"https://api.github.com/users/Graceson/received_events","type":"User","site_admin":false},"created_at":"2016-07-20T14:23:38Z","updated_at":"2016-07-20T14:23:38Z","body":"We also got stable hovering with the INAV method after tuning the MPC_XY_P parameter. But LPE is mich more better. Thank you @julianoes and @mhkabir  "}}
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