Pan troubles

Discussion in '3 Axis Gimbal' started by Gustavo Rios, Oct 10, 2012.

  1. Gustavo Rios

    Gustavo Rios Member

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    I have this problem with the pan, the first test all good but then this happens and I have no idea what it might be. Any ideas or suggestions?



    Thanks,

    Gustavo.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    You have the pan gain set too high, I think Gustavo. The "normal" value seems to be around 80. What you're seeing is the pan system oscillating.

    What is the current pan Radian sensor Gain value set to please?

    Andy.
     
  3. Gustavo Rios

    Gustavo Rios Member

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    I have 130 gain, savox servo in pan and 5v for all.
    I change now and test but with a first flight is no problems with same gain
    Gustavo.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    A pan gain of 130 seems quite high, Gustavo. Certainly what you showed in the video is the pan system oscillating. I know it only too well!

    Thanks
    Andy.
     
  5. Gustavo Rios

    Gustavo Rios Member

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    I tested with 70 gain and is better but I have not have fine pan.

    Gustavo.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah, 70 might be a little low -- try splitting the difference between 70 and 130, so go to 100. If you get oscillation, split the difference between 100 and 70 and go to 85, and so on. It's worth the effort!

    Andy.
     
  7. Gustavo Rios

    Gustavo Rios Member

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    Now when I move the stick of pan slightly to the right or left I have small oscillations.

    Gustavo
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    At what pan gain are you getting those oscillations -- there should be none if you get the gain set correctly.....
    Also check that the pan belt is tight -- pressing mid-way between the large and small pulleys should result in a 2-3mm deflection.

    Andy.
     
  9. Gustavo Rios

    Gustavo Rios Member

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    Gain 80, the belt is ok

    Gustavo
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmm. And yet you're still seeing pan oscillation? That's very odd. Just as an experiment: what happens if you crank the gain back to 30? It's obviously too low but it would be interesting to know whether the oscillation still occurs.

    Andy.
     
  11. Gustavo Rios

    Gustavo Rios Member

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    Yesterday turn the gain to 70 and still had the same oscillation, could be the servo savox not working as well as the FF ?

    Gustavo
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That's a question for Tabb on JohnC (who check this forum)....I'm only using the FF servos, but it sounds like a very valid question.

    Andy.
     
  13. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Gustavo,

    Yes the Savox servos do not tune as well with the Radian's. They are not tuned for camera gimbal use like the Freefly servos are.

    I would think this is where the difficulty in tuning pan is coming from.

    Best,

    Tabb
     
  14. Tabb Firchau

    Tabb Firchau Administrator
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    Gustavo,

    I don't think we ever sold a 360 gimbal with Savox servo? Or even a 3-axis upgrade with a Savox servo??

    Wondering how you ended up with a Savox on pan??

    Best,

    Tabb
     
  15. Gustavo Rios

    Gustavo Rios Member

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    Is true Tabb, first I buy 2 axis camera gimbal (two savox), after the 3 axis adapter kit (one FF), I read that this FF servos working better with radians and for this the change. I thought the roll has to be more efficient.

    Gustavo.
     
  16. Gustavo Rios

    Gustavo Rios Member

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    I change the servo Savox for FF and the oscillations disappeared, but now the problem is on the roll (savox), this tells me that the problem is the servo, the SAVOX not work well with radians as Tabb says. They said another thing to me, but well, I will have to change them.

    Gustavo.
     
  17. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Gustavo, It seems with some camera configurations the SAVOX work OK, with others they are difficult or impossible to tune with the Radians. I am not quite sure why the variance but you are correct the FF servo's work much better with the Radian. It seems that there is some inconsistency in the Savox servos. JohnC tested them quite a bit on a photohigher mount and they tuned up OK.

    Best,

    Tabb
     
  18. Gustavo Rios

    Gustavo Rios Member

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    Hi Tabb, the savox work ok in the tlit, for the moment, I donĀ“t know later, I think buy two FF and change all.

    Gustavo.
     
  19. Ryan J. Rowe

    Ryan J. Rowe Member

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    Hey guys,
    Been trying to smooth out pan. I'm getting a studder or jitter. Kind of a slow, fast, slow, fast movement. I've tried many gain settings. Can't go above 70 without craziness. I've tried stiffening and softening isolators, tightening belt and changing servos. Everything is balanced. Check out the clips. Hard to see in the aerial pan, but you should be able to see landing gear in ground shot with studder movements.

    Link to the video:
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ryan:
    Have you tried using exponential settings on the transmitter -- that seemed to improve the situation for me. I also used the dual rate feature on the transmitter to reduce the slew rate.

    Andy.
     

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