Please could someone help analyse this Autotune/Pixhawk crash?

Posted by Ben on September 16, 2016 at 4:00am

Was flying perfectly well on stock PID settings but wanted to see if autotune could improve things.

About 3 minutes into the tuning whilst still on the first axis it suddenly flipped over and crashed without any warning. It looked like an overly aggressive roll command caused it rather than a motor cutting out or stalling. Conditions were calm at the time.

It had completed about 90% of a previous autotune without incident but didn't have enough battery to finish, was in the air for about 15 mins without incident in autotune mode but had to land.

Sent it up again with a fresh battery, this time without any payload to help ensure sufficient flight time to complete tuning on single lipo (New C of G was accounted for by shifting lipo position) and the crash happened.

RATE_RLL_FILT_HZ and RATE_PIT_FILT_HZ were set to 10hz as recommended for larger props and battery voltage scaling of PID gains was setup..

Spec:

Pixhawk on a 900mm Y6 frame with T-Motor 4008-18 380v motors, 10000mAh 6S lipo, 15" props.

If anyone fancies looking at the log, it would be most appreciated - I've checked a few things but still unsure on the exact cause - possibly the default AUTOTUNE_AGGR parameter which I left alone as per the instructions was simply too high?

210.BIN

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Replies

  • Ben September 16, 2016 at 5:00am

    I certainly won't be using it again - had a pretty expensive crash! 

    Thanks for your help :)

  • Mikko Korhonen September 16, 2016 at 4:40am

    when i was tuning my px hexa, i had coupple of weird crash with autotune, decided not to use it at all. Yeah, if it was hitting gf, it should not defenetly crash, tho your px was on at mode,so who know´s? i think i cant help u too much, but i will be following the thread, im curious about this issue. Hope you find a solution :)

  • Ben September 16, 2016 at 4:33am

    I'm not sure - I was within the geo fence that was previously setup, so not sure if it somehow thought it was hitting the geo fence, or if the error actually means something completely different. If it is geo fence related, I still don't understand the way it behaved.

  • Mikko Korhonen September 16, 2016 at 4:16am

    i dont know too much about log´s.. What do you think that "fence" error in your bin file is ? 

    Sieppaa.PNG

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