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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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Replies

  • Mikko Korhonen September 20, 2016 at 3:17am

    i had same errors today. in gps mode, a sudden lost of altitude.

    I have had same thing before, so i was high enough to have time to change to STAB mode and make a save.

    Any info what is causing this? magnetic interference ?

    here´s log

  • Robert Caraway March 9, 2016 at 4:35pm

    Paul

    I am new to the forum and need to find someone with expertise in interpreting error.  I seem to get servo fluctuation while on the ground in FBWA mode as well as other auto modes.  I think this is traced to my IMU2 being noisy.  Any D that I add to Roll seems to be amplified by the noise.  I am not sure if this is normal noise or not.  I can see the plane twitch in the air from the gyro noise being modulated though the servos.  Any idea how I can filter this out?  I have attached a file of my plane sitting on the ground, no wing, no wind, no motor.  I did lift the tail at one point in the file.

    Any help would be much appreciated.

    Scot

    2016-03-07 12-31-46 7.bin.jpg

  • Tuloski November 10, 2015 at 4:45am

    Yeah, perfect analysis...in fact close to the ground the magnetometer goes crazy...from 40 to 70 degree offset.

    Thanks

  • Tuloski November 6, 2015 at 5:18am

    Hello, I had the same problem and my EKF4.SM are high, up to 2.0. What does that mean? What EKF4.SM are? How GPS velocities are used? And what do you mean by GPS velocities? The SoG coming from GPS?

    It seems the vibrations were fine and no big error on yaw.

    I attached the log.

    2015-11-06 12-24-58.bin

  • Andy Piper June 9, 2015 at 8:40am

    Response from 3DR "Given you are using beta firmware that we do not provide support for, you would need to flash current stable firmware to demonstrate ekf issues." So that's a no then :(

    I tried setting EKF_GBIAS_PNOISE as you suggested and have not seen any TBE since although I probably haven't gone as high either. Overall copter control is good, so I'm happy with this. Thanks for your help.

  • Andy Piper May 26, 2015 at 1:27am

    Hi Paul,

    Thanks once again for the amazing analysis! This seems like quite a subtle issue, do you think 3DR would accept it as grounds for RMA? If the pixhawk is faulty I'd prefer to get it replaced.

    I'll have to check my logs from the same day for similar occurences. Should I expect to see the divergence disappear as the temperature increases again?

    In your graph above 3.5 deg/second doesn't seem like a lot - it's hard to see in the graph, but you are saying that even this much discrepancy can cause serious issues? Did DCM learn the offset as well or is that new to EKF?

    Have you seen this thread at all:

    http://diydrones.com/group/iris/forum/topics/iris-massive-yaw-issue

    ? He has even more severe gyro drift, but it settles down after a while. Could this also be temperature related?

    Thanks

    andy

  • Andy Piper May 25, 2015 at 7:29am

    Hi Paul,

    So I loaded 3.3rc5, straightened the mast, recalibrated the compass, set declination manually and redid compass mot. I ended up with lower offsets and a much higher level of agreement between the compasses. I took it for a flight test yesterday and all was good. Took it for another one today in some wind and while performance was good, I still ended up with some yaw errors and a small toilet bowel. The log is attached. You can see I go quite high and the errors and TBE occur at higher altitude. I'm guessing this is because the wind was stronger higher up, but it's still disconcerting and a little worrying. Note that I pretty much go straight up - there is almost no forward velocity. I've got this tuned about as accurately as I can now, so I'm not sure what else I can do.

    Thanks

    andy

    2015-05-25 12-39-54.bin

  • luke cooke May 13, 2015 at 12:16am

    I have also Had this error once before, After much reading I came to the conclusion that it must be a DCM error. Finally tracked it down to the a yaw error. But still have no idea what caused it???

    It did only appear once and I havent had it again.

    It would be good if the error codes where better documented, and EKF changed to DCM in the code for APM users.

  • Andy Piper May 10, 2015 at 12:02pm

    Forgot the log

    2015-05-10 14-16-23.bin

  • Andy Piper May 10, 2015 at 12:00pm

    Here's a flight with 3.3rc3++ built from source and manual declination. This looks a lot better to me in EKF and bad but not awful in DCM. Would you agree?

    Have a look at EKF4->SMX at 12mins. There is a huge jump and it is again at the point at which MAG->MagY goes sharply down and crosses from +ve to -ve. I have seen this pattern before - downward transition crossing zero causes big error. Does this not look a bit suspicious?

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