Tilt servo Bucks wildly.

Discussion in 'Radian' started by nathan yant, Feb 15, 2013.

  1. nathan yant

    nathan yant New Member

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    I've just mounted Radians on Tilt and Roll on my Photohigher AV200 w/ Savox Servos. But when I power them up with my camera on them the tilt starts bucking violently. I'm putting a cannon t3i on it with a 10-22mm. The roll seems to be working perfectly. I took the camera off and the problem ceases. I tried to power up again with the camera balanced several more times, but the bucking on the tilt continues. Any Ideas? I'm chomping at the bit to do some test flights. Thanks securedownload-1.jpeg securedownload.jpeg co
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Nathan how about shooting a quick video. Your screen shot looks like it is setup correctly.
     
  3. nathan yant

    nathan yant New Member

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    I tried to shoot one with my phone, not quite sure how to upload it on this Forum.
     
  4. Gary Haynes

    Gary Haynes Administrator
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    Post it to Vimeo or YouTube. You can make it private with a password if you want. On the icon bar, click the screen button and paste the URL for the video location. Forum will then put it into the posting just like a photo.
     
  5. nathan yant

    nathan yant New Member

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    Sorry about the shaky cam, need a tripod for my phone
     
  6. Gary Haynes

    Gary Haynes Administrator
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    Can you take a screen shot of your Radian Config for the Roll Access? Let's see what some of the values are. Also have you balanced the camera/gimbal setup? Not sure how you do that on an AV since I don't believe there are any belts. Reason for this question is to make sure that you aren't out of balance and by adding the camera weight the servos start working to hard.

    Also if someone else is running Savox servos/AV200 maybe they can chime in on the settings that they are using.
     
  7. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Nathan,

    I am afraid the AV200 the way you have it setup will never work well for fast active stabilization. With the silicon dampers under the top camera plate the camera is able to flex back and forth. This allows the camera mass to flex / deflect as the Radian tries to correct and this creates a oscillation.

    Steps to improve:

    1. Remove top mounting plate and silicon dampers (I dont think these are a good design anyhow as when you point straight down the silicon chips are trying to shear
    2. Fasten the camera firmly to the camera plate. This is critical that everything is 100% rigid and solid. When the Radian commands a movement it is important that the camera, camera plate, etc all act as one solid unit.

    Hope that helps!

    Tabb
     
  8. nathan yant

    nathan yant New Member

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    Here you go Gary. The Tilt axis on the AV200 does have a pulley and a belt. I took the belt off and got it as close to balanced with my camera as possible.

    roll settings.jpeg
     
  9. nathan yant

    nathan yant New Member

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    Thanks Tabb, I'll try what you mentioned and see if I can get it to behave properly.
     
  10. Gary Haynes

    Gary Haynes Administrator
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    Nathan, on the balancing take a look at the videos on the FreeFly Systems YouTube channel. For balance you want to be able to tilt the camera and have it stay in that tilted position, not have it return to the 0 degree angle (level or straight up and down) if you can get it there. Don't know if that is possible with the AV200 but worth trying. Does a better job of taking the loads off of the servos.

    And kudos on shooting the video in a horizontal format. ;)
     
  11. nathan yant

    nathan yant New Member

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    Messed with the tilt quite a bit now. Took off stabilizing plate, tried rebalancing camera, and the bucking still occurs. Anyway this could be a bad servo?
     
  12. Tabb Firchau

    Tabb Firchau Administrator
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    HI Nathan, Have you adjusted the tilt gain?

    The AV200 has a very flexible camera plate and the twisting between the Radian sensor and the tilt drive axis can cause some big issues as you are seeing.

    Another thing to try is to mount the radian sensor on the other side of the tilt axis more near the servo and drive pulley. If you hold one side of the tilt axis in your hand and twist against the other side you will see what I mean, there is a lot of flex in the plate.

    Grab another video for us if you can also!

    Thanks

    Tabb
     
  13. nathan yant

    nathan yant New Member

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    Tabb, I took your advice and switched the Radian over to the other side of the camera tray where the pulley is located. I also bumped down the gain quite a bit. This defiantly took away most of the bucking. I haven't flown with it yet so I'm not sure how it will handle the little bumps. I'm wondering if you think it would be worth trying to rig the Radian on to the actually Pully the camera tray is attached to since it shadows the camera tray movements. Also, would buying your servos help smooth things out.
    Thanks again for your help
    Nathan
     

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