Yesterday I was flying in drift mode for a few minutes at high speeds up to 25-30 knots and doing very hard turns. 5 or 6 passes into doing this the APM seemed to have lost orientation. I was up at the top of a semi stall turn (at least what the quad will do) and when I leveled out at the bottom the quad would not respond as normal. I let it slow down and stop, and when stopped the yaw control (normal aileron but I was in drift mode) was banking the quad while I was not moving. In drift mode this should have only been a yaw input and if it was moving, it was way too slow for the bank angles the quad was using. I also noticed it was having issues keeping itself level. I gained some altitude and switched to stabilize and it flew fine. Is this something unique to my quad? Or is this something that happens in drift mode when doing sustained high speed flight?
Hmmm… this is interesting…
There can be a problem in drift mode if you are banking and yanking at high speeds (>15 m/s) but the problem is really only to do with the copter trying to turn to hard, and can start wobbling around, it goes away if you simply release the roll stick.
I can’t figure any reason why you would have had the problem you’re describing. Logs would help.
What you are describing sounds more like a general loss of orientation that is not restricted to Drift mode. I’ve done quite a bit of very high speed bank and yank type flying stabilize mode, and have never had a problem, though in Stabilize I guess it would be less obvious if the compass heading was off.
Logs?
I dont have the logs because I have flown probably two to three hours of flight time since the incident. What you described is probably what happened. I was moving pretty quick (25-30kts on telemetry) when it happened for a sustained amount of time. About halfway through the turn I noticed it wasnt behaving correctly and let it stop itself using the auto brake. Once stopped I tried turning it back towards home but what should have been only a yaw input because I had zero speed was putting a large bank into the quad. Along with the yaw and incorrect bank it was too much for me to figure out so i gained altitude and switched to stab and it was all ok. Is this just the sensors getting confused occasionally? I have flown in drift before for very extended lengths of time slowly, but never at sustained high speed for that long.
I’m still not sure if the problem you are talking about is the same as what I mentioned. But in neither case is it the “sensors getting confused”. If that were the case, it would happen in all modes, not just Drift.
I wonder if it’s possible that your problem was more related to a GPS glitch? That would affect Drift mode since it’s using the GPS for part of it’s control strategy. Without logs, impossible to say.