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APM 3.2 QUADCOPTER Err: EKF_CHECK-2 / Err: FAILSAFE_ EKF-1

Posted by Gonzalo Garat on December 15, 2014 at 4:26am

Hi all,

I'm attaching my log from our last flight as our little quad went completly bonkers before it crashed.

Short after takeoff it went completly out of control, no response at all from RC or Telemetry and then crashed near a pond (thank god).

But the mistery was about to begin when we started reviewing the log and found out that the trigger was the failsafe error  Err: EKF_CHECK-2 / Err: FAILSAFE_ EKF-1. 

In understand these two were recently added to APM, but this ain't the first time I see this sort of thing happening.

I'm attaching my log in hopes for some guidance.

Thank you all!

2014-12-14 11-10-14.log

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Tags: ekf, failsafe
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Replies

  • Mark Slater May 6, 2015 at 10:03am

    Looking at the logs there appears to be 4 problems that are consistent.

    1. The log reports EKF - it should be saying DCM (firmware error)

    2. Problems are with vibrations and building error - See vibration analysis in Mission Planner

    3. Almost always the trigger is large yaw - could be PID tuning or lack of torque, either way the yaw of the copter is not what the flight controller wants it to be.

    4. Old GPS unit without 2nd Mag - upgrade if possible.

    • Michael Keppeler > Mark Slater May 6, 2015 at 10:46am

      OK, here is my log.

      got a nice crash on that

      2015-04-12 15-26-02.log

      • Andy Piper > Michael Keppeler May 6, 2015 at 11:15am

        There's no IMU data that I can see so difficult to tell what's going on. No MAG data either.

        But your ErrYaw is very bad and that's why you get the error and why it hits the failsafe. The ErrYaw is calulated by examining the difference between the compass heading and the inertial heading. Bad compass puts the first out, bad vibrations the second. So check both.

      • Michael Keppeler > Michael Keppeler May 6, 2015 at 11:02am

        And another one...

        2015-04-03 15-57-24.log

  • Andy Piper May 6, 2015 at 1:49am

    Note that the error is actually from the DCM system even though it says EKF (it's a bug in the code that it says EKF) - this had me confused for a long time, until Randy pointed it out. So ignore everything the docs say about EKF - if you don't have it enabled this doesn't apply. That still doesn't fix the issue however :)

    • Ted Morgan > Andy Piper May 6, 2015 at 8:16am

      Well that makes sense then. Clearly I had a compass issue but the EKF failsafe concerned me since we are not using EKF.  Thanks for the help

    • WR > Andy Piper May 6, 2015 at 4:11am

      Update On mine. I took the board out of the case.. cleaned it with alcohole and a tooth brush.. examined it under a microscope and found NOTHING! looked good.. 

      I put it back in my quad calibrated everything and took it back out. IT WORKED.. no EKF.. anywhere in any log.. 

      Sorry I dodn't remember where, but in MP I found a EKF drop down that had nothing in it.. I set it to disable. not sure if that's whats fixed it or not. maybe just one time luck..

      APM 2.6 clone

  • Mark Slater May 5, 2015 at 9:29am

    Guys - I think I may have found the problem/bug - can you post a log each from the flight (please not the Tlog) the bin would be much better for what I'm looking at.

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