roll shake

Discussion in 'Radian' started by JY Air, Oct 17, 2012.

  1. MIke Magee

    MIke Magee Active Member

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    Hi Pavlos. I don't understand your question.

     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think Pavlos is asking whether the MR (Multi-rotor) was suspended or resting on a bench?

    Andy.
     
  3. Pavlos Antoniou

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    Exactly... Because mine with new motors i have it on the bech with cs skids and the numbers after balancing the motors was 0.015-0.035
     
  4. MIke Magee

    MIke Magee Active Member

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    I see. I removed the gimbal and legs, and placed the "MR" top end on a 1'X1' 1/4" foam pad. Please remember that I wanted only to compare the motor vibration w/o any other influences like the legs, support straps, etc. The goalwas to compare the motors to each other only.
    -m


     
  5. Pavlos Antoniou

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    hmmmm..! i think that there will be a difference on these..!
     
  6. Gustavo Rios

    Gustavo Rios Member

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    Hi,

    I have this small movement of the servo and I think is the cause of the oscillations that I have but not sure. This test is with 130 on the roll but I raise to 170 and still the same. any suggestions?

    Gustavo.

    http://youtu.be/OObHWW2KGiA
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    At what gain do you see oscillation in the roll axis, Gustavo?
    Also, have you checked the the roll servo belt is tight? (2-3mm deflection at the center of the gap between large and small pulley when pushed with a finger tip).

    Andy.
     
  8. Gustavo Rios

    Gustavo Rios Member

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    Andy, I check the belt and is within the parameter, the test I did with a gain of 130 in the roll, but the same result with 170 gain.

    thanks,

    Gustavo
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks, Gustavo. There's inevitably going to be some vibration - it should be damped.
    What happens if you have the gain below 130?
    What I do is change the gain by 10% up and down to see what changes, and then start changing by 5%, again observing the change, and then finally by 2% and then 1%. It's all too easy to "overshoot" the sweet spot with large percentage changes and not even realize that there is a sweet spot....

    Hope this helps.
    Andy
     
  10. Gustavo Rios

    Gustavo Rios Member

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    Andy, in flight, I tested from 60 to 130 gains and I have the same vibrations, which I find strange is that when flying with only 2 axis did not have this problem.

    thanks,

    Gustavo
     
  11. Gustavo Rios

    Gustavo Rios Member

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    The belt more tight could improve this?

    Gustavo
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Gustavo: yes, if the belt is too loose, then some vibration can occur just because of the slackness in the belt as the sensor/servo try to compensate.

    When you were flying with two axes, were you using a three axis gimbal and securing the gimbal to the motor booms -- or did you change the configuration of the gimbal back to two axes?

    Andy.
     
  13. Gustavo Rios

    Gustavo Rios Member

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    Hi Andy, only I checked previous videos were unstable but did not have this oscillation. (2 axis, servos Savox without radians).
    Well, I've re-balanced the camera and tight the belt more. I wait less or nothing oscillation.

    thanks,

    Gustavo
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    OK. Keep us informed of what you find, Gustavo.

    Andy.
     
  15. Gustavo Rios

    Gustavo Rios Member

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    Well, after of re-balance the camera, tight more the belt roll , I still have the same vibration, change the roll gain but not vary.
    One question, when activated radians, the servo camera (roll) must be completely fixed, no movement?, Because it is not my case, when I activate radians the roll not fixed I have a little game servo which I think is causing this vibration.



    Gustavo.
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Gustavo:
    Your video makes the gimbal look pretty good. Have you test flown with it? I think you may be at the point where only in-flight testing will tell you whether there's still a problem.

    Andy.
     
  17. Gustavo Rios

    Gustavo Rios Member

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    Hi Andy, everything what I mention are on the based of tests of flight.

    Gustavo.
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Gustavo:
    Hmmm. Then I'm not quite sure what you could try. You seem to have done all the right things.
    I wonder if any of the other forum members have some ideas that you could try?

    Andy.
     
  19. MIke Magee

    MIke Magee Active Member

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    Andy, My CS8 arrived in MT today with (as you know) very similar symptoms. I'll share their diagnosis and suggestions as soon as I get them. Hopefully they will resolve my issues with techniques that could benefit others. Keep all 10 finders crossed.

    -m
     
  20. Brad McGiveron

    Brad McGiveron Active Member

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    Gustavo... one thing I would do is show us some of your footage in the air with and without the radians on in the same flight.
    Also the gyro D MK tool settings should not be as high as 20 and more like 8-12 or you will get some rumbling vibrations that can cause the Radians to oscillate ( if you are using MK this is likely). The video you showed looks about right as Andy mentioned.

    But first some footage would help
     

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