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Gimbal Tuning In Windy Conditions

Discussion in 'AP/FPV' started by GPS, May 25, 2014.

  1. GPS

    GPS Registered

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  2. LEM504

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    Looks fantastic to me!
    Tell us more.
    Is this on the HEX?
    Controller?
    Gimbal?
    Are you using the Naza to control the Gimbal, or is it independent
    With it’s own controller?
     
  3. GPS

    GPS Registered

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    Thank you Larry. Yes, it is my hexacopter running a separate controller on the Tarot gimbal.
    It was so windy that the camera was causing a rudder effect on the whole airframe.
     
  4. LEM504

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    John,
    That is good news to me!
    I have one Tarot on the bench, and another on the way.
    I was getting cold feet and wondering if they were a mistake.
    The plan was to put one on the DJI 450 and one on the 550.
    Gopro 2 on one, and the Gopro 3 the other.
    Not exactly as simple as expected. Wish I hadn’t sold the old lathe.

    First problem, was my hang-up, about using the cameras without lens covers.
    Gopro has protective lens’s. Bought a pair, Now it got sticky.
    They are made to fit the Gopro 3. Friction fit.

    Of course the lens diameter is smaller on the Gopro 2, not to mention
    On a different location on the front of the camera. The 2 was also a few thousands taller and didn’t want to fit the mount housing. A bit of work with a file handled that.

    A simple aluminum plate for the front of the Gopro 2 handled the lens location problem. Crude, but it works. Needed longer screws to handle the
    Thickness of the camera.

    Back to the lens covers. The 2 wasn’t a problem. Just made the lens hole
    Large enough to seat the lens against the camera and hot glued it to the front plate.

    The lens cover for the 3 wouldn’t go onto the lens far enough to hold, with the plate mounted. Opening the lens hole on the plate wasn’t an option,
    Not enough metal. Did a quick test and found it wasn’t critical for focus
    And there was no cut off at the corners with the camera set for medium angle. Just hot glued it to the front plate.

    Now the protective lenses are mounted to the front plates, not the cameras.
    Next problem will be balance. I don’t expect it to be critical. The Tarot
    Isn’t balanced to begin with. Power off, and the camera hangs at an odd angle. I suspect the motors will handle that. If not, back to the wheel weights.
     
  5. GPS

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  6. LEM504

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    This lens cover would have solved all of the problems I had. OH well ---
     
  7. GPS

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  8. Tiger

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    The video looks great John. I take it this is something new? Whatever... It's doing a great job!

    ...Tiger
     
  9. Jonas

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    That looks pretty solid for a 2 axis gimbal as the horizon stayed pretty level throughout. But you're at the mercy of your airframe to keep the yaw stable in that case.

    To clear that up the yaw on a windy day, you need a 3 axis gimbal.

    If this is a 3 axis, then you just need to do some adjustments on the yaw PID settings.

    Overall the video looks great John.
     
  10. GPS

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    Thank you Jonas.

    Aren't three axis gimbals pan, tilt and roll (3 motors) and two axis gimbals tilt and roll (2 motors)? I have seen some gimbals on RC airplanes that are pan and tilt though for head tracking but usually on a multirotor for aerial photography there is no pan but roll instead. I think 3 axis gimbals with pan on a multi rotor are often used when there is a two pilot system, one for the airframe and one for the gimbal/camera.
     
  11. Jonas

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    Yep, pan (yaw) tilt (pitch) and roll.

    So think about your 2 axis gimbal, while you might manually set the pitch, for the most part the magic is in the stabilization of both the pitch and roll. to the 3rd axis is just extending that same magic to the pan (yaw).

    It can be set up to have manual control of the yaw if you have a camera person and a pilot, but that's not the general use case. You want that stabilization on the yaw to smooth out your airframe panning either under your control or the winds.

    So in the case of those windy jiggles you're getting there, it would pretty much wipe them out. BUT also, when you do manual pan with your Airframe, it can help smooth out jerks in that as well from getting to your lens.
     
    Last edited: May 29, 2014
  12. GPS

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    Thank you Jonas. I would like a 3 axis gimbal, but then I'd also like a Nex7 to hang on it too. ;)

    I'm not sure what I have the PIDs set to so maybe I can tune this better.
     
  13. Pelagic Pilot

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    We could put my Nexus 7 on a gimbal.
     
  14. GPS

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    My little camera is enough of a sail in the wind! I'm hoping GoPro will come out with a tube camera like the ReplayXD. I still think that is the chassis format best suited for AP.
     

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