EKF Fail Safe Error?

I've build a costume drone for fishing (actually casting bait) - still in development, made more than a few model - its 450mm, weigh around 1.8 KG.
works pretty well - but in the last two models are very unstable - sometime they work well sometime they are just unstable, yesterday I had two crashes (EKF Error)  - the log indicates it's an EKF fail safe. What actually happened is the drone past the RTL point, kept going and losing altitude until it crashed (meanwhile the RC didn't response)

Does anyone had the same problem? Does anyone knows what causes this? Any suggestions?
Log is attached.
Would really appreciate your help Thanks a lot!


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  • MR60

    We need to analyze more files.  What we've seen so far is that the processor still being able to keep the ship stable (it doesn't crash) but not responding to the mission.  So far we've seen the issue about 2% to 10% of the time, which makes it difficult to trace.

    We will keep you in touch via this thread as we bore down to the problem. 

  • Hi Forrest,

    Do you think that maybe the main processor is just ignoring the data stream from the ppm encoder ?

    My quad since about a year ago intermittently didn't want to arm, but in the field, and I didn't have a laptop to monitor.

    Back at home, it always armed and flew ok.....

    Did that about 3 times, always in the field without laptop :-(

    Then finally it did the same at home, with telemetry connected.

    No rc input on any channel.

    Now it stayed broken....

    I sequencially connected a small servo to the rx outputs itself, all was fine.

    That was with Hobby King apm.

    I then re flashed the ppm encoder, and it worked fine again.

    But I don't trust that apm, so I fitted an older 3dr apm, had to cut the mag trace to use external magnetometer.

    Now the quad fly's again, but somehow with the latest code I have issues with auto tune......

    Unfortunately I never kept track of what version software I was running :-(

    The Tx is a Spektrum DX9, and on the same day the quad had problems, I flew another model all day long......

    Very confusing, not going to update my Talon fixed wing !

  • MR60

    Three different UAVs in different parts of the world that we are testing periodically freeze and then slowly drift.  Sometimes by switching modes (auto or RTL to stabilize and then back a few times) we can get them to continue their mission or respond to other modes.  We've noticed this since about October, but that might be a coincidence as that is when we started testing more.

  • Mmm, I also had an RC not respond, fortunately on the ground, on APM 2.6.

    Turns out the PPM encoder intermittently goes funny, and does not pass through RC commands.

    Fortunately mine happened on the ground, and manifested itself as unable to arm.

    I was able to re flash the encoder part, but will put that apm in a car or boat for now!

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