Crash due to uncommanded yaw - log file analysis needed - Discussions

Can anybody help analysing the cause of this crash?

The copter started a test mission without any troubles and after reaching a waypoint, he started to yaw constantly but continued to follow the mission path.

After a couple of seconds the pilot switched out of AUTO mode into PosHold and then down to STAB, but the copter kept on spinning. The resulting oscillation of trying to get the copter stable and dealing with the ongoing spin resulted in a crash.

When I looked at the log-files, I can see the actual yaw following the desired yaw nicely. Until this very certain waypoint where the desired yaw goes up to 360, stays there for 3 seconds and then drops to 0 and stays there - all still during AUTO mode. When the desired yaw goes up to 360, the copter started its constant yaw and did not stop unitil crashed.

We are aware of the z-vibrations being not super nice, but I am pretty sure that this is not the cause of this behaviour. The copter holds it's altitude pretty nicely.

Frame type is a X8.

Any ides or suggestions?

Any help is greatly appreciated!

Regards

Marc

10.BIN

2016-03-09 17-34-25.tlog

Replies

- - - - Syrphus_AWO > leonardthall April 12, 2016 at 1:28am
        
        I tried to set the proposed bit-Code using the LogsFlags.exe for Windows.
        
        It's not exactly matching the Log options in my MP version but i hope this will give us the data you need.
        Waiting now for the rain to stop and then go for a new testflight.
        
        Developer
        
        leonardthall > Syrphus_AWO April 12, 2016 at 2:02am
        
        Hi Syrphus,
        
        Please just use the parameter I gave you. You can set it directly in the full parameter list.
        
        LOG_BITMASK,192509
        
        If you use IMU_Fast and IMU_RAW you will be logging too much data for a normal SD card and lose the data I want to see.
        
        Syrphus_AWO > leonardthall April 12, 2016 at 7:05am
        
        Hello Leonhardt,
        
        here's the log files of todays flights.
        
        http://www.filedropper.com/logs2016-04-12
        
        I did some interruption testing during mission flights and switched flight modes.
        
        Thanks for your help.
        
        Greetings.
        
        Alex
        
        Developer
        
        leonardthall > Syrphus_AWO April 14, 2016 at 3:40am
        
        Hi Syrphus,
        
        These logs look fine to me. The copter doesn't have the tightest control I have seen but it isn't having any problems.
        
        Vibrations look fine and motor outputs are reasonably balanced.
        
        You may want to double your Rate_I_MAX values for roll and pitch.
        
        There is a little more noise on your esc outputs than I like to see but nothing dangerous. However, this seems to be fixed in your last log.
        
        Well done!!
        
        Developer
        
        leonardthall > leonardthall April 15, 2016 at 4:30am
        
        Hi Syrphus,
        
        Sorry, I think those basic calibrations are just pass fail.
        
        Syrphus_AWO > leonardthall April 15, 2016 at 12:27am
        
        Hello Leonhardt,
        
        thanks again for your feedback and additional suggestions. I will check the higher rates for Rate_I_MAX.
        
        One final question with regard to all the calibrations that are done. Is there a way to see how successful these calibrations were done?
        How can i know about whether i achieved a good calibration result (i.e. accels, compass) and not just the digital feedback which states "succesful or fail"?
        
        Greetings
        Alex
        
        Cala > Syrphus_AWO April 12, 2016 at 9:06am
        
        Your vibes looks good but not your att, wait Leonard for better diagnose, perhaps you need tunning now.
        
        Syrphus_AWO > Cala April 12, 2016 at 3:04pm
        
        Hello Cala,
        
        thanks a lot so far.
        
        We did some test flights later again. Switched to different propeller blades (though also composite they are not that stiff like the ones we used before) and wanted to see the effect on the vibes. The vibes did not get better.
        
        But then we put some more weight on the pixhawks front and tail and significantly reduced the Z-Vibes. Also Compass looks good.
        
        http://www.filedropper.com/2016-04-1219-33-09
        
        I am waiting for Leonhardts judgement now. Also with regard to the ATT values you mentioned.
        
        Greetings
        
        Alex
      - Syrphus_AWO > leonardthall April 11, 2016 at 12:40am
        
        Thanks for the input, Leonhardt. I will do so and post a link to the new LOG-file tomorrow or the day after.
        
        Thanks
        
        Syrphus
    - Cala > Syrphus_AWO April 9, 2016 at 1:06pm
      
      Great news Syrphus :D ; in this log I couldn't find IMU to see IMU vibes and no Baro Alt too, but you still have something with your clips, follow that, but much better now, it's prefereable a flat line, perhaps It was something with gimbal, a rude movement or wind? Another suggestion watching your photos, perhaps If you can compact your frame, looks more easy to controller to work, I refer to distance with the colums don't looks optimus but if it flies well enjoy it.:)

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