Throttle doesn't work in X-plane 11 when try to enable servo in HITL mode

Pixhawk
1

I’m trying to enable real world servos while in HITL Mode. I’m using QGC version 3.5.6 and X-plane 11 and edited px4 firmware.
The files I have edited in order to make the servos work in HITL mode are:
i) Commented this line: https://github.com/PX4/Firmware/blob/b1dc1b1ecd479cc7d608f1d2df53f08fe45ecfb7/ROMFS/px4fmu_common/init.d/rcS#L357
ii) Commented this line: https://github.com/PX4/Firmware/blob/f160743df40b9dcc9558f3df1c6eeaf56646a758/src/modules/commander/state_machine_helper.cpp#L184

The result of this is that only airelon in X-plane 11 and one servo connected to Pixhawk works when moved with RC. And, no throttle,pitch,yaw works in X-plane 11 as well as other servos connected to Pixhawk also don’t work.

Thanks.

2

I got it working. This is what I did:

  1. I used the latest px4 firmware (v1.11.1 - also works on current master branch)
  2. I only changed one file (state_machine_helper.cpp): Commented the line armed->lockdown = true; inside if (hil_enabled) { block
  3. I compiled, built and then uploaded this firmware in QGC v3.5.6
  4. In QGC I disabled HITL then rebooted vehicle and then selected Standard-Plane as the airframe
  5. I pressed the safety switch to check if my servos are working as per the radio control.
  6. Then, I enabled HITL, again rebooted the vehicle and selected ‘HIL-Star’ as my airframe.

Note: At this point, the servos should still be active and controlled by radio.

  1. I launched XPlane-11 and started a flight
  2. In QGC, I opened the HIL widget to connect with X-Plane 11
  3. Then, I armed the vehicle

After arming; the real servos and the X-Plane aircraft wings should both be working and you should also be able to fly the plane using the radio.

I hope this helps someone