Pixhawk quad crash - help analysing logs

Posted by Tom Moore on June 20, 2016 at 9:36am

Hi,

I have recently set up a Pixhawk on a quad and the second time around a waypoint mission wanted to bring it down early in case the battery was close to being low. Just as I was switching to STABILISE mode it lost altitude and despite giving a full throttle command it continued to fall.

Fortunately it came through a tiny gap in the tree canopy and landed upright and seemed fine.

I'm inexperienced with analysing logs and wanted to ask for your help. Is there also somewhere I can go to and learn what I should be looking for after a crash to find out what caused it?

I wonder if the battery was too low to continue powering the quad but it flew for a longer time on the same battery previously.

Any help on this would be much appreciated. I've attached the .log and .bin and KMZ file so hopefully this is all that's needed.

Thanks, Tom

112 18-jun-16 10-49-28 pm.bin.kmz

112 18-Jun-16 10-49-28 PM.bin.log

112 18-Jun-16 10-49-28 PM.bin.log.xml

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Replies

  • Tom Moore June 21, 2016 at 5:53am

    Thanks everyone for the replies, that's really useful!

    Thanks, Tom

  • SkyRover June 20, 2016 at 4:48pm

    3702256956?profile=original

    • SkyRover > SkyRover June 20, 2016 at 4:52pm

      Looks like your copter ran out of juice. Whether from a battery not fully charged, or an underpowered setup I can't tell without more info, but you can clearly see in the picture the Throttle Out setting creeping up throughout the flight until its maxed out and it just isn't enough. I used to have the same problem with the Iris, the 9" props couldn't make enough thrust on hot days at the altitude Im at and it would fall down even at full throttle. In my case I fixed this by stepping up to a larger sized prop.

  • Clifton Hipsher June 20, 2016 at 11:43am

    3 minutes into the flight Pixhawk threw an EKF Check-2 error

    http://ardupilot.org/copter/docs/ekf-inav-failsafe.html

    There was no battery or current data in the log.

    Add that to the fact that you have no idea as to how your power system is performing you are very lucky the aircraft didn't crash sooner.

    Do yourself  HUGE favor:  Install a Power Module and setup the Low Battery Failsafe.

    There is more, but this should get you started.

    You can also find info here:  Pixhawk on RC Groups

    EKF Failsafe — Copter documentation
    • Peter Arnold > Clifton Hipsher June 20, 2016 at 2:54pm

      I think he is also asking for some help on reading and analysing the logs. Information on how to graph the log files is difficult to find and understand. I for one would like to find some information how to use the log graphs!

    • SkyRover > Peter Arnold June 20, 2016 at 4:53pm

      Check out this page for info on how to go through logs:

      http://ardupilot.org/copter/docs/common-mission-analysis.html

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