Yaw issues

New build with Pixhawk. My Yaw PID’s are still stock, I haven’t gone after them yet…

Here is the trouble… @ issues realy but maybe they are related.

  1. copter slowly oscillates back and forth in PosHold. It was significantly worse but I saw the external compass was slightly out of alignment with the flight control so I aligned by eye best I could. This seemed to take a lot of the oscillations out but it is still doing it. Slow back and forth.

  2. when asking the copter to YAW it does but when stick is returned to center there is a little bounce. When clockwise YAW and return to center the is about 15 degrees of CCW bounce…

I am going out tonight and re calibrate the compass to hopefully rule that out… I guess it makes sense that if you move it you need to re calibrate it… This is a large Hex so calibration is awkward to say the least…

I have noticed that the declination that I got from the prior cal and what the on line source says it should be is about 1 degree different…

My Stab Yaw is 4.5

Rate Yaw P 0.20
Rate Yaw I 0.02
Rate Yaw D 0.00

Any input would be greatly appreciated…


 There is an update in BETA firmware 3.3RC6 that is supposed to reduce yaw twitch due to an EKF error check. You may want to try uploading the beta firmware and see if that solves your problem. There is also a YAW Auto tune feature that may help fine tune your yaw control and prevent your stated yaw bounce back. Give it a try and let us know how it turns out.

Rc6 has some other issues and Randy has suggested no one uses it but sticks with rc5 for now.

I wait for firmware to be bug free and then give it a try… So, you don’t think YAW PIDs are the answer?

The yaw auto tune would have helped you tune your Yaw PID settings.

If you are having Yaw stability issues with the default PID settings then the yaw axis needs to be tuned. Try removing your Yaw I term completely and see if you still have such a drastic overshoot. Without the Yaw I term it should drift more on its own but you can see if it is related to the spring back effect you have described. If the spring back goes away with less Yaw I then slowly increase it until you have a good balance of heading hold without overshoot.