Pitch Ringing on Takeoff

Log Analysis -- deprecated Plane Logs -- deprecated
1

I’m new to Arduplane, running 3.8.5 on an mRo x2.1 (Pixhawk compatible) in my Team-Legit FOHDY 40" wing. I ran autotune and she flies nicely except for a pitch ringing (damped oscillation) on takeoff (hand launched) in FBWA. Autotune set PTCH2SRV_P to 1.05, but I reduced this to 0.9 hoping this would prevent the ringing, but it didn’t. See attached graph - CTUN.NavPitch (blue trace) is 12 degrees. CTUN.Pitch (red) oscillates with a period of about 0.25s. As soon as I switch to manual mode at the end of the graph this oscillation stops.

I notice that PIDP.D (purple) is very active - does this look like D-Term oscillation? Parameter file attached. (I tried to attach the log file but it bombed out).

Thanks for the help!
Andrew

TakeoffPIDs
TakeoffPIDs.png1313×617 15.7 KB

FohdyAP011.param (14.3 KB)

2

I reduced PTCH2SRV_D from the autotune value of 0,084 to 0.04, which solved the problem.