Use gamepad/joystick in ALTCTL mode

Hi Everyone

This is my setup

gamepad (logitech f350) -> QGC -> wifi -> raspberry pi -> telemetry 1 -> pixhawk (PX4 flight stack)

I set COM_RC_IN_MODE to 1 (disable RC check)
I am able to fly quadcopter in stabilize/manual mode quite well. But when I switch it to ALTCTL mode, I can not take it off using gamepad. Increase throttle do not increase motor spin rate. If I take it off in stabilize mode and change it to ALTCTL mode, nothing happens. Quadcopter lose altitude if I release throttle stick (just like stabilize mode, you have to hold some throttle to let quadcopter hover). However AUTO_LOITER mode works quite well. Do I miss something? Or gamepad / joystick is only for stabilize mode only?

Thank you very much

You need to make sure you’re sending the correct range for the joystick. At alt control it will only hold altitude if you have the joystick centred. If it zero then it will interpret that as a command to reduce altitude.

If you fix your joystick output to the correct range it will work. There is no issue with PX4, its the incorrect data you’re feeding that is creating the issue.

Hi LorenzMeier

Thank you very much for your help
I will check mavlink packets send from QGC and joystick config