APM 3.2.1 Random Twitching on Stablize mode

ArduCopter Copter 3.2
1

Good Day Everyone,
I’m new to this forum though i’m not exactly new to APM. Build couple of quads with APM and all went well…until i recently upgraded firmware to 3.2.1 on my APM 2.6 and have experienced some random twitching (Sometimes increase in altitude–akin to punching short burst of throttle). And all these have been happening quite randomly, just this morning, i experienced shortly(Without crash) on take off and after that the flight went on uneventfully for 10 mins or so.

The copter flys very well after auto-tune with solid loiter and RTL. But only thing that bugs me is the random twitching that almost cause me to crash at times. I have did some bench testing on motors/esc and i’m fairly confident it may not be mechanical/ESC related.

The log attached was a short test flight where the twitching occurs.

Would like to seek you guy’s opinion on this issue. Thanks and Safe Flight Always.

Regards,
Dan

2

I think i may have confirmed the cause of the issue. It could be caused by failing 3.3V regulator during the flight that causes surge in SPI speed and causes the twitch. The regulator finally gave way and output un-regulated 5V to the sensors which now, i could not event boot up the MPU6000 or connect via the mavlink.

I’m going to improvise some 3.3V regulator into the APM to revive it. Awaiting parts from ebay now. Stay tuned for updates.