I am a embedded SW engineer but a total newbie with PX4. Built my own drone as described in the topic title and it does not fly stable. I need some help to figure it out from the logs.
Problem description: After few minutes of stable flight, I was hovering approximately in 1.5meter height with negligible controls. Suddenly, the battery low beep was triggrered (i was actually testing the beep and thus had set it to trigger very very early) and at the same time the drone jumped approx. 1m higher. I pulled the throttle down to stop the rise, but could not catch it and the drone came down with a few jumps breaking its landing gear (it is heavy). The drone remained level all the time, so i cannot believe it would be a motor/ESC problem.
I am linking the log below. The event starts at 215.640. I do not really know which items I should describe here, but some observations:
* The RC controls remain stable - not my fault
* The IMU values seem normal and only change at the time of event (cannot judge if reason or result)
* The ATTC values tell that someone requests attitude change (again cannot judge is this reason or result)
* The ATT values tell that the attitude is changes at the exact same timepoint with all the other events
* The OUT values tell that the output changes at the exact same timepoint with all the other events.
* The BATT values tell that the battery warning kicks in slightly after the other events, so seems to be the result of motors starting to take more power
What could be the issue? I do not dare to fly it atm. There were similar issues earlier but they could've been for some bad electrical connections and I do not have log for them. Sure I can upgrade the firmware but I would need to know that something related to this has been fixed and I could not find the changelog anywhere.
Log available at: https://drive.google.com/open?id=0BxykaYXTxO4rQXFIVGM5TnhwV00
I will be thankful for any ideas!
EDIT: Manual flight mode, GPS connected but should not be in any use.