Before I updated to Cleanflight 1.14.2, I was having vibration issues – causing my Loki 130mm quad to drift while in a hover. In random directions. And a drift that increased with time. Made stable flying (angle mode is my preferred stable flight mode) untenable.
So, while still on CF 1.14.1, I started doing physical modifications to the stack, while quantifying my accelerometer data via BlackBox logging.
Besides adding the O-rings on both sides of the OSD and FC, I removed threads from the white screws holding down the FC to the stack – such that the screws would be less likely to contact the sides of the FC. Also, I unpinned the OSD from the FC, and used wires instead. All this was done to decrease likelihood of vibrations moving from the craft to the FC on the top of the stack.
You can see the final result of this work, in the stack shown in the main picture for this blog, at the top of this post.
That work seemed to help, just a little, and not very much – it was hard to quantify any real changes via looking at the logs – and I still had drift issues during flight. So …
What did make a huge difference, was upgrading from CF 1.14.1 to CF 1.14.2. The accel RMS was about 100x less. And the before and after accelerometer graphs as viewed in Blackbox Explorer – they speak for themselves.
What a difference. Yowsa!
Why? Well after scouring the solved issues list in the Cleanflight GitHub, turns out that the accelerometer code was broken in release 1.14.0. Further, the new filters weren’t applied as well. Both these were recitified in 1.14.2 though.
Weird part is that I’ve been using Cleanflight, rather than Betaflight, to avoid these types of issues. Hmmm … maybe I need to indulge in some CF release candidate testing. Because obviously that’s been falling short. Or, use Betaflight.