Robocob movements in all 3 axis :(

Discussion in '3 Axis Gimbal' started by Oscar Ruperti, Jun 4, 2013.

  1. Oscar Ruperti

    Oscar Ruperti New Member

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    Hi.
    I have been adjusting the cinestar 3 axis gimbal and it is almost perfect. And I say almost, because I have a big problem I can't resolve. All 3 axis are very smooth when they are already moving. But at the very first start up of movement it starts with a very rigid and robotic movement wich is not smooth at all. That's what I call robocop movements. For example; I am moving pan and after a few seconds I need to tilt, the result is that you notice very much the tilt starting point movement because it kinds of starts like sudenly with a strong start and it ruins the footage. Its like working with a bad tripod with no silicone friction. starting a movement in any direction is like a robot, you know what I mean, I cant combine pan and tilt movements like as one only movement....
    If been messing around with expo and dual rate on the futaba ff8 and the radian software and I cant get that silicone smoothness at the starting movement.
    I am a professional camera operator and I know exactly what a smooth starting movement is, and radian doesn't give that smoothness at all.
    Anyway I can understand why it doesn't. It's impossible to get that smoothness with electronic gyro and geared servos. The only way I've been able to get real smooth starting movements is with these gyros http://www.ken-lab.com/ but of course handholding the camera....
    The problem is that they are way to big and heavy for even a big octocopter!!!!

    So, I will be really happy if there is any body out there that can help me solve this problem. Thanks!!!!

    Oscar
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Oscar:
    The things I've tried are (a) lots of expo, (b) using Dual Rate on the transmitter, and (c) reducing the slew rate in the pan Radian sensor.

    However, nothing is going to get you as smooth as a fluid head as the Radians do not support ramping...

    Andy.
     
  3. Oscar Ruperti

    Oscar Ruperti New Member

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  4. Oscar Ruperti

    Oscar Ruperti New Member

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    Thanks Andy.
    I was thinking about adding myself a little bit of friction fluid on the gimbal axis, maybe only on the tilt axis. Of course that would make the servo do some extra effort, but maybe not so much and it might be an option to avoid radical start and stop....
    It would probably also affect the stabilization itself creating a delay in the gyro system, but in my RC helicopter experience, some gyros have a delay knob to adjust the tail rotor compensation, depending on the helicopter itself.
    Do you think it might work? Have you experienced something like that?

    Oscar
     
  5. Scott Stemm

    Scott Stemm Member

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  6. Oscar Ruperti

    Oscar Ruperti New Member

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    Thanks Scott.

    Looks cool, but does it solve the easy start and easy stop? I can't notice in the video :(
    I've seen some new gimblas with brushless motors that seem to run really smooth, but dont know if they have the same start and stop problem.
    Whatever, I think this should be the next step in all kids of gimbals and I really hope manufacturers find a solution. At least for the footage I need smoothnes is very important.
     
  7. Scott Stemm

    Scott Stemm Member

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    From what I seen he is able to use ramp up and ramp down which smooths out the movement. I would love to get one but right now the price is a little more than I am willing to pay.
     
  8. Tim Joy

    Tim Joy Active Member

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    Not to be hash, but this is where skill and a steady hand come in. :) (in addition to the proper settings with expo and rates)

    There could be other factors- Are you using long lenses? If so, the servos really need to be geared down to get that fine resolution.
    or, if you use some lenses with image stabilization, then it might cause a jerky start.
     
  9. Oscar Ruperti

    Oscar Ruperti New Member

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    Hi Tim.
    Yep, good hands have a lot to do, but if electronics don't support ramp control there will always be a tough start...
    What do you mean by servos need to be geared down?
    In the next footage we will be using a canon D5 with 20mm lens

    Thanks
     

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