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Cesna Pixhawk Crashed in FBWA . Autopilot wrong???

Posted by Wilson Frias on September 4, 2014 at 11:20am

Hello everyone.


Today I tried to fly a small Cessna 182 with pixhawk and everything seemed fine until I activated the FBWA mode. I started flying manually and take off  with difficulty because it is a little heavy, but when I thought   was stabilized I activated FWBA  and the aircraft went crashing to the ground. Reviewing the log I see that the commands I was sending to pixhawk were completely contrary to what I was doing with my radio.

I'm right ?? below the flight logs to see if someone can help me.

Thanks in advance

2014-09-04 12-04-44.bin

2014-09-04 12-04-44.kmz

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Tags: cessna, crash, pixhawk
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Replies

  • Wilson Frias November 25, 2014 at 5:52pm

    Hello to all!!!

    Here is my parameter file is someone is interested in Pixhawk on a Cessna 500 Class

    Parametros Cesna Rev 1B.param

    https://storage.ning.com/topology/rest/1.0/file/get/3701881986?profile=original
  • Wilson Frias November 19, 2014 at 3:24pm

    Here it is!!!!!!!

    Working!!!

    http://youtu.be/jNy_vxHcPu8

  • Wilson Frias November 5, 2014 at 4:41am

    Hello Everyone:

    I'm trying to find out what happened. I would love for someone with more experience could help me with the interpretation of LOG flight.

    What happened was that after flying a bit in the AUTOTUNE mode switched to FBWA mode. Everything worked as it was supposed to and I decided to move to AUTO to fly a mission that was previously loaded.

    When I lost sight of the plane I moved a bit but I could not see what was happening. I put it on again FBWA manner and under the log indicates the airplanes being inverted turned around, ending finally hitting the ground.


    The weird thing about this is that so FBWA could not exceed 40 degrees of roll !, so do not understand how she turned

    Here are the links to log telemetry and video screen mission planner.

    https://www.dropbox.com/s/bmpcjpddyqjw28b/Crash%20cessna%20500%20co...

    https://www.dropbox.com/s/4lp3r75o8imksp0/2014-11-02%2015-15-20.bin...

    https://www.dropbox.com/s/qw2a41f0vh2gsu6/2014-11-02%2015-15-20.log...


    Thanks in advance

    3701867203?profile=original

    Dropbox - Error
    Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
  • Flying Buddha September 4, 2014 at 8:19pm

    Sorry about your crash...Your not alone, same thing happened to me with my first APM. Plan on "tinkering", sometimes you can get lucky and find a good parameter file for your airframe and sometimes you have to start from scratch. Its taking me about three weekends now to get my new ArduPlane tuned to my liking.  

    I've put together a couple planes (and copters) using the APM and Pixhawk...and every time I still get very nervous just before flipping the switch into an AP mode. Altitude has save me so many times.

    Good Luck

    • Wilson Frias > Flying Buddha September 4, 2014 at 9:01pm

      Thanks. Have you see my log?? Its there another problem that I haven't notice?

  • Andre K. September 4, 2014 at 2:45pm

    two major mistakes here:

    1:you tried to blame it on the "autopilot"  - Just realize that until you are very familiar with this advanced piece of technology, any mistakes, crashes, and failures are most likely to be a user error.  :)

    2: you must set up your pixhawk so it's output is *correct*  ,  instead of just setting up your radio so that it flies in manual and hoping autopilot will "guess" corect actions.  Simply said: the autopilot was set up to use the elevator in opposite direction of what's up - when it wanted to go "up"     - set Stabilize mode, and check control surfaces movement on ground.

    • Wilson Frias > Andre K. September 23, 2014 at 12:17pm

      Andre:

      This happen again. This time I did every thing by the book and gess what??? 

      Just when I change to FBWA, the plane rotates uncontrollable. I went back to manual to try to save the day but it was too late. The plane smashes into the ground.

      I do Check all the control surfaces in manual and in FWBA mode

      Any Ideas.

      Here is my log

      • Andre K. > Wilson Frias September 23, 2014 at 12:30pm

        I see no new log.

        but the question remain: did you set it up correctly ?

        If it flies in manual:   switch to manual, hold plane in hand, apply left aileron, - observe deflection that you do.

        now switch to stabilize,  - roll plane to left , what does the ailerons do ? - do they work against that roll, or do they the opposite of what you would have done to stop it from rolling left ?

        test the same for pitch, as I am not sure if you actually mean roll or pitch , or both are inverted.

        • Wilson Frias > Andre K. September 23, 2014 at 2:53pm
          switch to manual, hold plane in hand, apply left aileron, - observe deflection that you do.

          That's what I do: When I apply left aileron the right Down left Up

          This is a litlle video with the issue:

          https://www.dropbox.com/s/83g35tlhhhfrz2l/Comportamiento%20Pixhawk%...

          Dropbox - Error
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          • Andre K. > Wilson Frias September 23, 2014 at 11:08pm

            It's like I thought; your roll response is inverted. 

            you must get your ELEVON_MIXING right.

            Basically: you must set up the plane so Pixhawk's output are correct in stabilize, and then, and only then, set up your RC so the RC does what you expect in manual mode.

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