I’ve noticed a problem in my setup. I think it doesn’t have to do something with the described pich movements when roll is commanded. But just to be sure…
The cyclic deflections of my swashplate are not symmetrical. I can measure 6.2 deg when I roll to the right and 8.4 deg with roll left. Of course I checked it on 0 deg of collective and also with H_COL_MID set very precisely. It doesn’t have something to do with my mechanical setup because all my servo arms are perfectly horizontal and also I can see in the servo monitor of Mission Planner that my Pixhawk is commanding a greater servo travel to the left than to the right. Of course I had to make some adjustments to the servo trims in ardupilot. They look like this:
SERVO1_TRIM,1542
SERVO2_TRIM,1580
SERVO3_TRIM,1480
(Servo 1 is left, 2 right and 3 on the rear.)
Could this cause the problem? E.g. ardupilot is trying to prevent the servos from binding? But in reality there is enough space for the movements.