Alexmos 3 axis....glitching

Discussion in '3 Axis Gimbal' started by Devin Card, Aug 24, 2014.

  1. Devin Card

    Devin Card Member

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    We've been having fantastic results out of our Alexmos but now get a glitch coming about ever minute or so. Anybody experience this. The boards is the new board from aerial pixels....
     
  2. Dave King

    Dave King Well-Known Member

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    What kind of glitch?
     
  3. Devin Card

    Devin Card Member

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    It seems to be a quick little twitch a couple off mm on the roll axis that make it go up and down and then settle back in to normal movement...only about once a minute...maybe compounding I2C errors, but not really getting much of that on GUI
     
  4. Dave King

    Dave King Well-Known Member

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    Do you have the upgraded roll bar and twin tilt bars? Also are you running 2 IMU's?
     
  5. Devin Card

    Devin Card Member

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    upgraded tilt but no roll. only using one IMU....was working properly for a while so feels like an electronic glitch
     
  6. Dave King

    Dave King Well-Known Member

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    Have any footage? The updated roll bar makes a big difference. One thing I noticed on using a regular 25mm bar is that the roll balance has to be absolutely perfect not to see any roll twitches.
     
  7. Devin Card

    Devin Card Member

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    Everything is perfectly balanced. Here is a clip. It will also just glitch out sitting on the stand or holding in hand held mode,
     
  8. Dave King

    Dave King Well-Known Member

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    Says the video is private.
     
  9. Devin Card

    Devin Card Member

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    should be fine now
     
  10. Dave King

    Dave King Well-Known Member

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    Are you referring to the tilt jerk at 4 seconds? What motors are you using? How balanced is the camera? Can you put the camera any where on the tilt axis and it should be rock solid and not move? If you haven't done so I recommend putting this on the output of the alexmos that goes to the IMU http://aerialpixels.com/shop/access...id-cores-alexmos-brushless-gimbal-controller/

    Lastly I would recalibrate the ACC and Gyro for the IMU sensor.
     
  11. Devin Card

    Devin Card Member

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    Yup the jilt at 4 sec. Using GB 85s. Everythign is perfectly balanced. Can put cmaera anywhere on tilt axis and its rock solid!! We also have ferrite rings on both ends of IMU cables. We recalibrate ACC and Gyro every time we use it :)
    We are stumped....
     
  12. Dave King

    Dave King Well-Known Member

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    There's 4 things that come to mind, a bad motor, a bad alexmos, a bad IMU or a bad IMU cable. One thing you could try that wont cost anything is to switch the motors on the pan and roll since they are the same. To me this is a tilt issue not a pan issue so if you switched motors you could see if it goes away. IF that doesn't work you could switching out the IMU cable which is cheap and then the IMU and alexmos in that order. Maybe you could also try to reinstall the firmware to the alexmos.
     
  13. Devin Card

    Devin Card Member

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    Hi Dave ,
    Thanks for the help!
    Well Ive tried switching out all the items as you suggest but not the motors....its my last hope
    Its a pain, because I get the smoothest footage on the ground and in the air except for these jerky movements randomly
     
  14. Graydon Tranquilla

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    Devin, If you are still having issues, the newest firmware offers the option to put in notch filters. At certain angular positions the BG can start to resonate which can lead to issues such as the glitch. Using an acoustic spectrum analyser program to work with your PC or smartpad to work with your device microphone should be all you require to ID the resonant frequency.... then add the notch filter to cancel it out.
     

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