Mikrokopter Afro Esc Weird Behavior

Discussion in 'Cinestar Misc' started by Marcelo Vaccari, Dec 8, 2014.

  1. Marcelo Vaccari

    Marcelo Vaccari New Member

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    Hello,

    I wonder if some of you guys could help with this issue I'm having. I started flying this quad multirotor a couple of weeks ago and it was really smooth. I tested a few battery setups and all seemed ok. A couple of days ago I tried to arm the quad and one motor didn't run. I checked the i2c cables and noticed one of them was disconnected. After connecting the cable I re-started the procedure and made a couple of flights, but this weird behavior started to happen: It looses stability and accelerates all in a sudden, and gets really difficult to maintain control. It seems to get better or worse when changing battery packs, so I initially thought it could be related to battery voltage. I lowered the battery voltage cutoff to a minimum, but it doesn't seem to make any difference.

    I also played with PID, lowering them, but no effects on the problem.

    I re-flashed 3 different firmware versions (V0_78b, V2_00f and V2_08a) on the flight ctrl board, and tried 2 different firmwares for the afro esc controllers, but nothing seems to change.

    Here follows my setup:

    Mikrokopter Flight Ctrl Board 2.0
    AfroEsc 30A
    Axi 2820/14 motors
    APC 14 x 4.7 slow flyers
    4S battery packs tested:
    GensAce 6600
    GensAce 10000
    GensAce 12000
    Hyperion 5000
    QuadroPower 6200

    Here follows the link for the video of the last flight:



    Any comments are welcome.

    Regards,

    Marcelo.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Marcelo:

    I'm not sure if we can help you too much as this is the Freefly Systems support forum.
    That said, have you used the Mikrokopter Tool "motor test" to try each motor independently?

    Andy.
     
  3. Marcelo Vaccari

    Marcelo Vaccari New Member

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    Hello Andy, thanks for the reply.

    To answer your question, the motor test runs perfectly. The strange thing is that the behavior changed all of a sudden. It was flying incredibly smooth one day, and then that you can check at the video. Do you think something could have happened to the flight control board? I do have a navi ctrl board and GPS to solder and put together to try and log some flights, but I was wondering if you guys have seen this behavior before, as its so strange.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I suspect that it might the Flight Controller that has gone bad. Do you have a spare you could try?

    Andy.
     
  5. Marcelo Vaccari

    Marcelo Vaccari New Member

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    I'm afraid not. That's the only one I have. Thanks anyway Andy.
     
  6. Marcelo Vaccari

    Marcelo Vaccari New Member

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    Andy, how are you? Just to let you know, I finally found the error. I did a lot of research and found some very similar behaviors on other multicopters that had soft arms. After building a new frame on aluminum, the errors disappeared. Cheers.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Marcelo:
    Nice to hear that you figured the problem out -- sounds like it was just the arms bending that was causing the problem!

    Andy
     
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  8. Marcelo Vaccari

    Marcelo Vaccari New Member

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    Yes, at the beginning the arms were stiff enough, but after a few flights they probably lost the original rigidity and started bending. That explains why they worked before.

    Marcelo.
     

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