Left Right Mystery

Discussion in 'MōVI MR' started by Adam Etheridge, Apr 1, 2014.

  1. Adam Etheridge

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    Hi Guys

    Thought I'd try and start a fresh thread for this one. We've been having on going issues with our Movi MR, in that it won't produce a stable image. It appears to judder / fidget and render all shots useless (see video link below), but with one curious exception.

    In the "Tracking Left" shot, it looks almost perfect. However when we change direction and Track Right, the problem returns. We've had exactly the same thing happen on 2 days, with very little wind.

    http://exchange.aspectfilmandvideo.co.uk/judder-tests.mp4

    We're desperately try to work out what this might mean, and if it might help us identify our problem???!

    Everything is very finely balanced in all three axis. We've balanced all the props and removed the big wheels on the legs. We're flying:

    SkyJib v1
    Allied Echo Mount (8 x Soft Dampeners)
    Movi MR - Stiffness settings: Pan 100, Roll 52, Tilt 38.
    Red Epic (20mm Canon Prime with side handle)

    Any thoughts / expert opinions greatly appreciated.

    Adam
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Adam Your pan gain sounds a little low. How are you adjusting the gains? Are you hanging the entire rig or some other method? You might also try the harder dampers for the Allied Drones adapter.
     
  3. Adam Etheridge

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    Hi Gary - we tried suspending the rig, but found that wasn't very accurate, so instead we put it in a hover and adjust in flight using an HD feed. What makes you think pan stiffness?
     
  4. Gary Haynes

    Gary Haynes Administrator
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    Others have posted that they have higher readings on pan. You may be the first trying to tune while flying.
     
  5. Brad Meier

    Brad Meier Active Member
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    If it's fine one way but not the other... I would guess pan balance. Did you do both steps of pan balance?
     
  6. Adam Etheridge

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    Hi Brad - I didn't know there were 2 steps for balancing pan!?...

    We hang the system by 2 booms, vertically on its side. We then move the pan knuckle back and forth, until it can rotate to any pan position and stays where its (without wanting to spin back down to earth!) - are we missing a step?
     
  7. Sam Leggett

    Sam Leggett Member

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    Yes Brad is right - I don't want to steal his thunder but just in case you are waiting and it is still very early in the States I'll carry on! You slide the pan knuckle back and forth to make the movi sit still in one plane... then you rotate the gimbal 90degrees and repeat. To adjust in this plane instead of moving the knuckle back and forth you need to tilt it slightly off vertical. This is not easy to word but you can see it here:

    http://forum.freeflysystems.com/index.php?threads/mōvi-tutorial-videos.2123/

    Our pan stiffness was about the 90 mark - with the wheels - we haven't adjusted for no wheels yet but will do. Our picture though is really good with no wobbles in the pan axis.
     
  8. Gary Haynes

    Gary Haynes Administrator
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    Adam please go to the Freefly website and review the MoVI training videos. There is one available on balancing the Pan axis. It is a two step process. While it is outlined in the owners manual makes a bit more sense when you see it shown to you.
     
  9. Adam Etheridge

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    Hi Brad / Sam / Gary - thanks for this... not sure how we missed that, but we were only doing the first - will try this and report back.
     
  10. Adam Etheridge

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    Hi Guys - I stand corrected, having spoken to our crew apparently we have been balancing pan using both steps...

    Also just for clarity, we're not seeing this strange discrpency when panning Left / Right... its only when we're flying Left / Right.

    The Mystery continues :(
     
  11. Chris Fox

    Chris Fox Active Member

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    G'Day Adam,
    Can you post a picture of the way you have the MōVI set up, do you have anything attached to any of the landing gear legs?

    Cheers
    Chris
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Adam: is this something that you can cause on the ground by, say, have someone hold the copter and run/fast walk left/right? If it's reproducible on the ground then it would point to an issue with the MōVI itself. If you cannot reproduce it on the ground then it's something to do with being airborne/aerodynamics -- which is where I think ChrisF is headed. :)

    Andy.
     

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