Need help on understanding crash cause

ArduCopter
1

Hello there.

I made a quadcopter that flew very well since I made it a week ago. I made ~30 flights without any problem, but today it wasn’t the same.

5 seconds after taking off, the gyro went crazy and thought the drone was flipping over, which caused it to crash as I was in stabilize mode. I didn’t have the time to realise what was happening that it already crashed.

I can’t understand what went wrong this time. What caused the gyro to act like this ?

Here is my FPV feedback

Here is the flight log

Thanks a lot

2

You’ll need to unlock the flight log so it can be downloaded.

I did notice in the video that the arming checks have been disabled. You should turn that back on. Also in the video there is a GPS glitch. All clues, but the log may tell more.

3

Sorry I thought sending the link would be enough. Just fixed it

I disabled arming checks when I was running motor test on the bench and I didn’t take the time to reenable it.

Thank you

4

You had an EKF failsafe triggering Vibration Compensation. This is triggered when the position estimate is poor. You can read about it here and graph the parameters and see where the condition was met.
Vibration Failsafe

You haven’t calibrated the compass?

5

Thank you for those precious informations.

I calibrated the compass at the very beginning but inside my house. Should I recalibrate it outside ?

I finished repairing the quadcopter and I’m waiting to be sure my problem is fixed until I takeoff again. Don’t want to take the risk to damage it more (it broke one propand sent the battery 20 meters further away).

I feel like I was lucky on this crash as it really didn’t do any serious harm to my quad.

6

There are no Compass offset saved so the calibration was not successful.
COMPASS_OFS_X,0
COMPASS_OFS_Y,0
COMPASS_OFS_Z,0

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7

I agree with Dave, you need to calibrate the compass. Take it outside and get a good GPS lock before you begin the calibration.

I’m also wondering if you’re getting some throttle interference, but the we can look at that after the calibration is done. Do a short flight after the calibration and if you’re concerned post the new log.

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8

I recalibrated the compass and everything looks fine now :smiley:

I made a normal flight without any problem.

Thanks a lot for helping me guys!

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