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!
Replies
Wow - only the first part of my post appeared....
It should say - I think you need to tidy the cables first, they will tug on the pixhawk and cause vibrations
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.
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.
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 :)
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
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.
Here is mine from the Pixhawk. You can see the error at line 30305
15-04-30_16-28-02.bin
Later on in the log it looks like bad vibrations, but the initial error looks like the OP - huge requested Yaw triggering an EKF fail error. Your ErrYaw is also huge all the way along, so you should look at the vibrations anyway.
Opening Post
You have bad vibrations. You should fix those - it is the cause of most of your problems.
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