I have a quick question about setting up a camera gimbal for my 3DR (version A) hexacopter using an APM 1.
I recently purchased this camera gimbal: http://www.quadframe.us/collections/camera-mounts/products/gopro-2-axis-gimbal-for-ll4-and-other-frames
It uses two of these digital servos: http://www.quadframe.us/collections/parts/products/emax-es08md-servo
Following the instructions on the wiki, I'm running the gimbal tilt and roll control from channel 5 and 6 of the APM 1. I also configured channel 6 (the rotating knob on my Spektrum DX7s) to control the tilt axis. I'm currently running firmware version 2.7.3. I use the 3DR 900mhz radios for telemetry.
The latest version of Mission Planner has a GUI configuration screen for the gimbal that differs from the parameter-based configuration in the wiki. However, by setting min/max PWMs for the servos and experimenting with the angle values, I am able to get the gimbal working. Unfortunately, the motion of the gimbal is very jerky/jittery on both the tilt and roll axis. When I plug the servos directly into my Spektrum rx unit, they operate smoothly. I have also made sure that the servo linkage on the gimbal isn't too tight or sticking.
Any suggestions on how to get the gimbal operating more smoothly? In other posts where users are experiencing the same problem on the APM 2, it seems that switching channels on the APM sometimes solves the problem. Because I'm using 6 channels on the APM 1 for the motors, 5 and 6 are the only two available channels.
Also, I'm curious about how the gimbal configuration controls in Mission Planner work. For example, how do the neutral angle and control angle settings impact the function of the gimbal? Any help is greatly appreciated!
Replies
Digital servos do exactly what they are told, some of what you are seeing is just the precision of the control system hard mounted to your gimbal axis. I think analog servos work better for camera control, especially a direct drive system such as yours. It's like listening to music from a analog record player versus a digital CD.
The first thing to do is put ferrite choke filters on your servo leads, be mindful of your cable routing, etc. A multi-rotor is an electronic rich environment with many sources of signal noise.