My APM 2.6 quad has failed to disarm.

As a noobie I am asking for someone to review my data log. 

I have a 500 series quad that I purchased pre-built. So far I am very happy with it but have had a couple of occsions where it would not disarm and I had to unplug the battery. 

When this happened the first few times I thought it was my error. But recently I am more confident my actions should have disarmed the quad. Also this seems to happen when landing in RTL or Loiter. 

Saturday it was windy and area of launch a bit restricted, so I chose to use RTL as the GPS modes (loiter, RTL, and auto missions) have been spot on. Upon touch down I placed left stick full down and full left. The props almost came to a stop then suddenly sped up just enough for a hover less than a foot of the ground while at full left yaw. Needless to say it touched back down and flipped over. I have attached the data log from this event. 

On my next battery I landed in stability mode and was able to dis arm with no problem. 

On my third battery I got into some brush causing a crash and again I could not disarm with left stick down and left (loiter mode). Log for this event not attached. 

I don't fully understand how to graph all the info but was able to show altitude, throttle in, and throttle out in screenshot also attached. I think this shows throttle input was correct but APM over-rode and raised throttle for some reason. 

Thanks in advance for reviewing the attached log.3691272890?profile=original


2016-01-30 12-31-29.bin

2016-01-30 12-31-29.log

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  • With APM 2.6 you need to turn up logging so we get more data to help with the issue.  The default is 830 and needs to be set higher so it will record RCIN and RCOUT which will tell us what you did and what the motors were doing.

    Recreate the problem and after that set it back to 830 as higher logging effects the flight controller performance.

    • Michael I appreciate the quick reply and apologize for my lack of knowledge in APM. 

      What BITMASK setting are you suggesting? In the link you provided I do not see an option that covers both RCIN and RCOUT?

      Also can you explain what you see in the graph I attached? I thought this showed throttle input (geeen line) was null but APM called for throttle up (blue line)?

      Also what effects might be expected with higher logging?

      • No, this is what the copter was doing not your input.  You need to set it to NearlyAll.

        When landing the copter it must think it has landed or it will not respond to your input to shutdown.  You can not shutdown the copter while it is flying only when it has landed.

        • What effects might be expected with higher logging rate?

          What data does arducopter use to determine it has landed?

          • That I don't know.  It slows down the flight controller as it is too busy to keep up with current tasks so they recommend that the logging rate be set low for most operations.

            For testing it should be fine with no noticeable effects.

            You will see lots more data in the logs though which will help with problem determination.

          • I would recommend you to go over, all the basic calibrations, you may have missed something out, or not completed it properly.

            When performing the calibrations, take your time and don't rush through them.

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