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Massive vibration/shutter/wobble

Discussion in 'Phantom 2 Discussion' started by lachers, Feb 21, 2014.

  1. lachers

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    Hey guys,

    In previous topic i mentioned that i was trying to mod a gimbal for my P2V so i could use the stock camera with a 2 axis gimbal. I managed to short out the camera and have since decided to use my GoPro Hero 3 to do the job.

    I went to just have a test flight while i wait for the last of my new FPV gear to arrive and test out the gimbal with the GoPro but appear to have run into an issue.... The whole Phantom shakes, I'm not talking just the gimbal having a bit of jello shake, this is something you can hear all through the phantom and the motors trying to adjust for it.

    Here is some footage of it flying, it's hard to hear over the wind from the props, but you can hear that this is not just a jello problem. You can physically see the Phantom shakes and this footage shows how its a fast and fairly aggressive shake.

    http://www.youtube.com/watch?v=kf1QvFfFM5w&feature=youtu.be

    The gimbal function works fine, camera keeps still and level and i have tested different softness rubber dampers, but this seems something more.

    Is it because of the gimbal sitting so low that the balance is off? I chose this one as originally i was trying to fit the big vision camera in.
     
  2. goldfishrock

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    The video is showing as private?

    How heavy is your P2 rig with all this kit on it?
     
  3. lachers

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    Public now - it randomly decided to make it private.

    Not sure what it weighs in at, don't have scales sensitive enough:-(
     
  4. ianwood

    ianwood Taco Wrangler
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    I've seen this before. The gimbal and the Phantom are fighting with each other. I don't recall the specific fix but I think it has to do with how the gimbal is mounted. Maybe gain settings as well but not sure. Can you post up a pic of the gimbal mounted up to the Phantom?
     
  5. goldfishrock

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    Wow! I see what you mean.

    I'm not convinced that the gimbal is at fault. I've watched the vid a few times and it looks like the shudder actually starts prior to it lifting off the ground. This would almost certainly rule out the gimbal being the culprit.

    OK, couple of things to check. Have you got a spare set of props? First thing I would do is swap all the props just to rule those out.

    Secondly, after it's landed, immediately just touch each of the arms and motors to check for heat. If one feels warmer than the others it may indicate either an ESC problem or a motor on the way out.

    Have you altered your gain settings at all in the Assistant software?

    You also mentioned about shorting out the camera... can you explain what happened? Was it connected to the P2 at the time. Just trying to rule out anything electronic that's failed as a result?
     
  6. lachers

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    ok - going through the list -

    Props - i havent tried a different set, but i did rotate the props to see if maybe it changed at all if the were reversed, but no significant change.

    Short Circuit - possibly a fault, but i would be comfortable at saying its maybe 95% not the problem, the short only happened when plugging in the cable via an adapter cable to give a little extra length. The cable carrying the power, video and ground to the Vision camera, just happened to kit one of the other contact points and bam it burnt the camera unit out, not appearing to have effected the main board.

    Gimbal - here is a video of the gimbal as i was testing with the original Vision Camera, it kinda shows it off best.....
    http://www.youtube.com/watch?v=0DDzR5My8dw

    Here is are some general pictures of the setup
    [​IMG]
    [​IMG]

    Gain - I had thought maybe this was an option - i had an old quadcopter (Gaui 330x) old school and it had a shake similar to this, i had to do an adjustment to the gain and it seemed to fix that issue. Whats the best way of adjusting the gain, on my old Gaui it was a turn the screw to adjust the gain, does the phantom assistant software allow you to so it electronically, if so, do i go up or down???

    Thanks for the help so far :)
     
  7. goldfishrock

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    If you download the Phantom 2 Assistant Software (and windows driver is you are using windows) (http://www.dji.com/download/phantom-2-downloads/). This will allow you to change the gain from the 'Basic' screen in the software. I would say you maybe want to reduce the gain a little in each of the Pitch, Yaw, Roll & Vertical and just play around tweaking it and see if that makes any difference.

    Looking at the video I am hazarding a guess that it weighs in at more than the 1300g limit which could well be part of the problem too. It's impressive looking through!
     
  8. EMCSQUAR

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    You need to download the BGC software to adjust the gains on your gimbal. The gimbal gains appear to be to high or needs the basic calibration offered from BGC depending on your software version. You can load the default settings from their site also (I think it's now called Basecam) Don't bother adjusting gains in asst software.
     
  9. lachers

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    Ok - Changed the gains... Id say things are about 90% better

    I started reducing in 10% increments and found that 90% was too low, and stuck at 95% for the final figure. The hovering became erratic and couldn't hold a position at 90%.

    95% seemed to remove most of the issue, still not perfect but i think the most of the rest can be fixed more with a bit more balancing in general of the gimbal and fine tuning of the camera balancing within the gimbal. Those random glitches at the extremes are because the go pro hasn't been weighted correctly in the gimbal. Then video software can do the rest ;-)

    Check it out - happy to accept more advice if you think there is more to do to help :-D But either way - thanks for the helps so far!!!
    Note - I'm and in a small courtyard at home and was flying around erratically to test it out... There is still a little shake coming through though.

    https://www.youtube.com/watch?v=LEEvfHDoWxc
     
  10. goldfishrock

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    Yeah, that looks a lot better. I think you're right, the rest can probably be corrected with some light tweaking to the balancing and setup

    Good News :)