Hello,
I'm trying to figure out if my APM board is broken or not. While my copter is flying in stabilize mode, it often suddenly change its orientation. First, I thought STB_YAW_P & STB_YAW_I would be too large, so I reduced these values. However, the undesired behavior didn't stop. I finally reduced the both STB_YAW_P & STB_YAW_I down to zero.
This happens even when I don't touch the yaw stick at all. (although it is possibly that I unintentionally move the yaw stick when I control the pitch)
The below is the log that shows YAW_IN and YAW. I also attached the log file. It looks pretty odd to me. I appreciate any advice you might have to fix this problem.
Thanks.
Replies
Those big jumps you're seeing are not an issue - the yaw is being reported in centi-degrees between 0 and 36000 so as it crosses north you see a sudden jump when it goes from 360deg -> 0deg or vice-versa.
I've had a look at your logs and it appears you're getting radio glitches on channel 4 input to the APM.
If you're using a high speed Futaba transmitter with at least 8 channels, there have been reports of issues in which the APM's ppm encoder is not able to keep up with the messages from the receiver because they all arrive at nearly exactly the same time (most other transmitters don't sent all messages simultaneously..they're normally sent one after the other). This problem can be resolved by upgrading to the latest ppm encoder. instructions are here.
As a side note, I see you have a lot of dataflash logging turned on. We've found that this can cause performance issues so best to keep it down to just the items that you're investigating at the time. You should always leave ATT, CTUN and NTUN on though in case you need to investigate a crash.
Great to see that you're investigating your log files!