After upgrading my tricopter flight controller to KK2.1 from KK2.0, the original settings does not work anymore. Although I can make roll and pitch perfectly stable now, I was having tricopter yaw unstable problem. The yaw simply does not stay at the centre, and the tail servo just moves left and right. I first looked at the hardware first, which wasn’t the issue. But if you have the same issue and haven’t done those things yet, give them a try.
- Balance prop and motor
- Make sure yaw mechanism is not sloppy, and movement is smooth.
- Use Digital Servo rather than Analog Servo (if you are using the tricopter for FPV and taking videos, it’s always best to use digital servos, which is more precise and faster)
The answer to my problem was actually settings on the KK2.1.
I first make sure the channel used for the servo is set correctly.
Mixer Editor- Channel 4 - change Servo from Low to High
Be aware this is only for digital servo, setting it High will damage analog servos. Also remember to adjust Offset to make sure tail is at its centre position when hovering
I then lower PI for yaw, it does solve the wobble issue for me, but with low yaw PI gains, the yaw response become slow. However, I tried to increase servo filtering.
Misc Setting - Servo Filtering - change 50% (default) to 70%
This allows me bring yaw PI gains back up without having the wobble issue.