I am trying to get and S800 Evo flying smoothly to waypoints on a pixhawk with Arducopter 3.1.2, however despite playing a lot with the PIDs I am still getting uncomfortable twitches when changing between loiter-based flight modes (e.g. Loiter->Auto-RTL and so on)
Looking at the logs I can see that not only is the S800 twitching when I switch from, say, Loiter into Auto mode, but that also the DesPitch itself seems to be temporarily twitching, inverting after an overshoot. That I don't understand.
I can understand why actual Pitch might overshoot a computed Desired Pitch when as it tries to home in on the new required lean angle to fly to a waypoint, but why is the DesPitch itself oscillating, and even inverting here? Is this an IMU / Gyro / Vibrations issue? I have got vibrations down to well inside the +-3 recommended band, and the pixhawk is mounted on the damped IMU board under the S800.
Graph and log attached for any that might shed some light!
(in log see around 14775 for example, towards the start. test also repeated 7 or 8 other times in the flight)