U8 II KV85
28" folding Polymer props
Initial flights went well. Performed Autotune for roll axis. Announced error (autotune failed, cannot level) but it did complete and produce new values.
Performed Autotune for Yaw, same error message. Autotune completed.
Stabilize and Alt-hold are very stable. I was really comfortable on the sticks. As soon as I switch to Loiter mode the vehicle begins to oscillate.
The oscillations are not toilet bowling however. It seems to be rotating about motors 1 and 3, with motors 2 and 4 seesawing.
Below is a google drive link containing two logs. Was hoping someone could take a look and maybe see whats going on as I enter loiter mode.
Any help is appreciated.
Did you ever resolve this issue? I have had similar problems on my drone too (T960 frame, 6S, 18" props).
I recommend using the notch filter outlined in the Ardupilot wiki Tuning section. Then Autotune.
I know it’s been a while since you first posted, but try these and see what happens, post another .bin log if you like
Update the CAN GPS firmware
Update the Arducopter version to latest stable
Connect to MissionPlanner, Initial Parameters, put in your battery info and accept all the battery-related settings it offers. Including:
I would highly recommend FENCE_ENABLE,1 since this is big, expensive and potentially dangerous.
You just have to wait for a good GPS 3D Fix and (wait a bit more) for Home to be set.
Harmonic Notch Filter is doing nothing, set this:
Also set this and let’s see what is going on:
This will reduce the yaw severity a bit and might allow a bit better pitch/roll attitude control. Having these yaw P/I values too high can induce some yaw oscillation at arming. Changing these is not essential.
This should settle down the oscillations in Loiter: