VTOL: MC throttle drops when front transition is initiated

[sfuhrer]

Describe the bug
When a front transition is started, the MC throttle shortly drops:

This usually results in some altitude drop.
It is mostly noticeable if the vehicle is slightly climbing before the transition happens.

In sitl, there is also a short drop (shorter than for the real vehicle). This could well be related:

I would prefer a smoother transition on the MC throttle from hover to transition.

[sfuhrer]

@MaEtUgR could this be the position controller resetting when the transition starts (i.e. when switching flight tasks)?

https://github.com/PX4/Firmware/blob/master/src/modules/mc_pos_control/PositionControl.cpp#L112

[sfuhrer]

When climbing strongly right before transition it can look like this:

This seems to come from a step in position sp, that the controller then aggressively tries to follow. Giving up of alt control during transition and instead only controlling altitude change (vz) to 0 could fix this issue.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. Thank you for your contributions.

[sfuhrer]

Let's close this. I haven't seen it happening again in recent flights.