Fly away in Loiter Mode and Crash - Pixhawk

Dear all,

Today I tested my quad for the 1st time with the Pixhawk FC. I use to fly with DJI. I followed the "first flight" instructions and took off in Stabilize mode. All went well: good response, directions were as they should be. Only I noticed that the quad was hovering with throttle at 35%. I adjusted Throttle Hover setting down to 390. That went well: hover at 50%.

I continued testing in Stabilize mode, checked vibration values (seems to be ok), adjusted Climb Sensitivity to 0.64 and RC Feel Roll/Pitch to 95.00.

Then during hovering, I switched from Stabilize to Loiter...: the quad started to drift toward the left. Just as someone commanded a Left Roll input. Trying to correct it didn't help and as I was hovering only 1 meter above the ground, before I realize what was happening the quad tilted further and kissed the surface. Luckily, the location where I flew was covered with high grass and somewhat took some of the impact. It didn't prevent one of my 15" carbon fibre props to break.

As I have no idea what caused this "fly/drift away in Loiter" I hope one of you can analyse the attached log file and explain me what happened.  2014-11-01%2012-17-28.log (i believe this is the Log file when it crashed)

2014-11-01%2011-51-26.log (log file of quad in Stabilize mode: good behaviour)

Any help is appreciated.

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Replies

  • I am suffering from the same phenomenon.
    What are the causes of these symptoms?

  • i tried looking at your logs files but you need to enable more logging because its not enough, 45054 should be enough on the logging parameter to get RCIN and RCOUT

    you are also running AC3.1.5 - consider moving to version AC3.3.2

  • Check you compass direction,if the direction is wrong,the control will be opposite. Sometime you need flip your direction in the initial setup. 

  • Results from the auto analysis for the first file you provided:

    Log File C:/Users/Aaron/Desktop/Google Drive/RC/Flight controllers/Ardupilot/logs/20141101121728.log
    Size (kb) 139.076171875
    No of lines 2101
    Duration 0:00:15
    Vehicletype ArduCopter
    Firmware Version V3.1.5
    Firmware Hash ee63c88b
    Hardware Type PX4
    Free Mem 65535
    Skipped Lines 0

    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Balance/Twist = GOOD -
    Test: Brownout = GOOD -
    Test: Compass = GOOD - No MAG data, unable to test mag_field interference

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = GOOD -
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.22, WARN: 0.75, FAIL: 1.50)
    Test: Parameters = GOOD -
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = GOOD -

    • And the second file:

      Log File C:/Users/Aaron/Desktop/Google Drive/RC/Flight controllers/Ardupilot/logs/20141101115126.log
      Size (kb) 3651.205078125
      No of lines 50124
      Duration 0:09:55
      Vehicletype ArduCopter
      Firmware Version V3.1.5
      Firmware Hash ee63c88b
      Hardware Type PX4
      Free Mem 65535
      Skipped Lines 0

      Test: Autotune = UNKNOWN - No ATUN log data
      Test: Balance/Twist = GOOD -
      Test: Brownout = GOOD -
      Test: Compass = GOOD - No MAG data, unable to test mag_field interference

      Test: Dupe Log Data = GOOD -
      Test: Empty = GOOD -
      Test: Event/Failsafe = GOOD -
      Test: GPS = GOOD -
      Test: IMU Mismatch = GOOD - (Mismatch: 0.38, WARN: 0.75, FAIL: 1.50)
      Test: Parameters = GOOD -
      Test: PM = GOOD -
      Test: Pitch/Roll = GOOD -
      Test: Thrust = GOOD -
      Test: VCC = GOOD -

      • Dear RonHogwarts, Thanks for this reply and your time checking the logs. Since this 'accident' I had enough successful flights, but was never able to figure out what happened. Even by looking at the info you provided, I'm not sure what I

  • Additional info: I did a proper GPS/Compass calibration before the first flight and when I tried to fly in Loiter, the Pixhawk locked to GPS (flashing green LED).

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