Gimbal suspension too soft

Discussion in '3 Axis Gimbal' started by Marc BRACELET, Aug 25, 2012.

  1. Howard Dapp

    Howard Dapp Active Member

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    Thank Josh. Yeah dialing in expo ain't going to cut it for us, its gotta be a feature set with a range of adjustability via software.
     
  2. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Hopefully it will be added in. I too would like to see that.

    Josh
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Howard: I been struggling with the same thing myself (albeit calling "easing in" and "easing out.") I've tried two things: large amounts (e.g. 60% of exponential control on the sticks, and slowing (on the Radian betas) the slew rate to 20 degrees. I can certainly improve matters, but, if I slow the slew rate way down (e.g. 10 degrees per second), I'm starting to see what I think might be the individual servo "steps."

    I was working with a professional shooter and we came to the conclusion that for really smooth panning, it was best to yaw the C8 itself -- our theory was because the mass was sufficiently high that there is natural ramping.

    Regards
    Andy
     
  4. Howard Dapp

    Howard Dapp Active Member

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    Thanks Andy. Yawing the ship maybe a panning solution for a certain type of shot but I can think of a hundred other types of shots where yawing the ship in order to get a smooth pan would disrupt a planned run. To be honest this functionality should be in software already if i'm to pay over $1000.

    Walter's hacked MK FW works amazingly well (for me) if you dial it in correctly and use fast servos. The only issue I have with the MK board for gimbal use is roll stabilization performance during fast sideways flying.

    I just hope ramping adjustment is eventually added to Radian. That would be amazing.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I agree that Walter's firmware was remarkably good, but as you say, the high speed traverse with the camera at 90 degrees to the line of flight a bit iffy. I was wondering whether what was actually happening was that the vibration isolators were being laterally displaced and hitting the frameset? There would be a reasonable about of lateral slipstream on the gimbal and camera so I could see if generating a fair amount of buffeting.

    I don't know enough about the Radian's firmware, but assuming there's sufficient code space, ramping should be feasible, I would have thought.

    Thanks
    Andy
     
  6. Howard Dapp

    Howard Dapp Active Member

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    No, it's the accelerometers causing this phenomenon, not sure of the technical terminology but I call it accelerometer noise;) affecting the gyro, I believe better filtering between the gyro and accel may help..not sure there. I've used a number of IMU solutions and so far all of them are in some way affected by this.
     
  7. Howard Dapp

    Howard Dapp Active Member

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    Hi Josh,

    As a beta tester have you requested the ramping feature? Have you gotten any feedback? If ramping is not avail at release, will it be added in the future via fw update?

    Thanks for any info.
     
  8. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I have mentioned it to Tabb. Not sure whether or not it will be added in yet.

    Josh
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I was out shooting with a 5DM3 + 24mm prime yesterday for the first time. So, heavier payload and no image stabilization like I'm used to with the CX760 and noticed that there was a definite "wobble" -- I could see it on the video downlink from the camera. I brought the C8 in front of me and put it into hover, and with the yaw/pan sensor disabled (to eliminate that as the cause), could see that the whole gimbal was very gently wobbling in the yaw axis -- the tilt and roll servos were not operating (or were operating minimally) -- it appeared to be at about, oh, 4 to 6 Hz (that's just a guess). I'll get a better read when I look at the video later today.

    The temperature was about 75F / 24C, so warm, but not blazingly hot. Tabb's away on a shoot for a few days and I need to go back to get some additional shots, so I was wondering whether anyone has found a supply of stiffer O-rings? I can fix the wobble in post, but would rather minimize it at source.

    Thanks
    Andy.
     
  10. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Im still having some wobble issues... even with the stiffer O-Rings... not sure what the deal is... Im going to keep playing with stuff.

    Josh
     
  11. Mike Hagadorn

    Mike Hagadorn Member

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    I have been having the same issue since the beginning. I am running a little different setup but have never been able to get rid of the slight wobbles associated with the vibration isolators. My fix had been hard mounting the gimbal plate to the airframe. Has been working pretty well. Several time I have tried to go back to the isolators as I have seen alot of people using them with success.
     
  12. Howard Dapp

    Howard Dapp Active Member

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    I bet most folks would not experience any shaky video due to vibrations if they hard mount their gimbal. Give it a try!
     
  13. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Just an Idea:what would happen if we slide in between the o rings a cylindrical silicon piece so to help stiffen the o rings
     
  14. Howard Dapp

    Howard Dapp Active Member

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    Or soft foam to dampen/cushion.
     

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