I made my own gimbal system from some 3d printed parts and two servos (tilt/roll control). I tried to plug the two servos in to RC channels RC9 and RC10, and configured them appropriately in APM Planner. I have my 4s lipo hooked up to an ESC with a 5A BEC, which I have connected directly to the servo rails. I can control the servos no problem if I hook them up to RC channels 1-4, but they don’t respond at all when they are connected to RC channels 9-14. Even when I try to manually trim them using channel 7 (one of my analog knobs on my tx), they won’t respond. The raw servo outputs don’t change at all when I move the pixhawk around and the stabilize box is checked.
Is there something I am missing in the setup of a gimbal system with pixhawk?
I have been perplexed for some time trying to understand why not all of the main outs would move a servo (as an example) despite the fact that channels 5-8 all register pwm signal changes in the ‘Radio Calibration’ area of Mission Planner. I think i have finally begun to understand why this is. In general, the only ‘Main Outs’ that will actually drive a servo or motor are the ones that are mandatory for the model firmware you’ve loaded. So, for arduplane (ele, thr, rud, ail [channel1-4]) and for Hexacopter (motors [channel 1-6]). For any other ‘Main Outputs’ to drive any non-default items could result in problems if you plugged in a servo or motor lead in the wrong spot.
Having said that, i have gotten this working on my plane for my pan/tilt (2 servos) on channels 5 and 7 of the ‘Main Out’. See image below for how i configured the Camera Gimbal. In the full parameter list, these settings are called MNT_RC_IN_PAN, MNT_RC_IN_TILT, RC5_FUNCTION, RC7_FUNCTION respectively. In my case, i wanted to provide stick input for tilt in addition to having the Pixhawk stabilize the tilt of the camera.
Figuring this out was the key to understanding the main outputs on the pixhawk which had been confusing me for weeks.
