Pann axis gitter

Discussion in 'Radian' started by Laurence Hamilton-Baillie, May 27, 2013.

  1. Laurence Hamilton-Baillie

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    Hi guys me again! So got my gimbal set up and working now! Just in the process of tuning up the gains. In the Pan axis though, the whole gimbal oscilates back and forth as if the gain was too high. I have turned the gain all the way from 100 down to 50 in 10% increments and the gimbal still oscillates. what do you think could be causing this? are my vibration isolators too soft/hard. I think they were too soft because the gimbal does shake a bit too much in flight (see video) I have the blue rings and am just flying a go pro at the mo so it they shouldn't be to soft should they??


    Laurence
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    If you're just flying a GoPro, the payload is probably too light for those gain settings. Do you have a heavier camera you can try -- or just strap a house brick to the gimbal as a dummy load.

    For a GoPro you just have to keep cranking the gains way down -- it's all about how much mass in motion you have. Also you might want to experiment with a lower slew rate on the Radian settings and using lots of Expo on the radio transmitter so you can accelerate/decelerate the gimbal more gently to avoid the aggressive start/stops that can induce oscillation.

    Andy.
     
  3. Brad Meier

    Brad Meier Active Member
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    Most of your oscillation looks to be roll. You did have some pan movement but it looked like it was low gains causing the issue (low gains cause a softer movement while high gains create high freq oscillations). I would run those pan gains back up to 100 and start playing with the roll gains. If you change cameras, you will have to make all the adjustments again.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Laurence:

    Would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/

    Could you also take some images of your gimbal so that we can see how you have it set up and where the Radian sensor is, please?
    Also, most of what I see in your test video is instability in the roll axis -- but that's one of the axes where you do not have any stabilization, so that is to be expected. I do not see wobbling in the pan axis -- or if there is any it is insignificant compared to the wobbling in roll.

    Thanks
    Andy.
     
  5. Laurence Hamilton-Baillie

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    soz bout the name, changed now. yeh the video just shows the general shaking rather than the pan axis gitter. I did have stabilization on all 3 axis for this flight! should my roll gain be higher i wonder? Turns out the pan gitter was because the pan belt was way too loose. Tightened it up and that sorted the gitter right out allowing me to raise my pan gains again.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Laurence: Thanks for the name change. Yours is a fine surname (as anyone with a double-barrelled surname will tell you -- and as they are called in England).

    Try shooting some video without the Radians switched to Mode OFF. Does the jitter get better or worse? If better, then you will need to tweak the Radian gains -- probably by adjusting them down. If it gets worse, that means that the Radians are compensating but not enough so you'll have to tweak the gains up.

    Andy.
     

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