roll shake

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

  1. Gary Haynes

    Gary Haynes Administrator
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    Phil your video in Post 121 has disappeared.
     
  2. Philip Ellerbroek

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    Brad

    How do you mean by "slop"? You mean a gear was stipped?

    Also, can we replace gears if this is the issue?

    Phil
     
  3. Brad Meier

    Brad Meier Active Member
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    I feel like its a limitation in all servos but less in Freefly servos. The tolerances are tight... any kind of hard landing where the servo may be forced suddenly could cause a little wear on those gears. In my case I believe it happened before I had the gear extenders on. With my extended down tube the adjustable tilt bars only had 1/8 ground clearance. Probably hit the ground a few times and stressed the roll servo.
     
  4. Philip Ellerbroek

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    Brad,

    Well that would likely explain my issue. Just prior to this beginning to occur in my videos, I had the unfortunate experience of the vertical shaft the the roll servo resides on slip out and the entire camera and gimbal tray fell 3 feet onto the grass and it likely jammed the roll servo quite a bit.

    New servo arrived today.

    Phil
     
  5. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Phil, Let me know how that works.

    I have not swapped my Roll servo out. It's still the original one from FF when I bought the gimbal.

    Josh
     
  6. kjetil tønnesen

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    video is coming up soon with the steadyshot off ,off the sony 730
    uploading it now:)
     
  7. Philip Ellerbroek

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    Josh

    I'm hoping this is the fix. Trying to fly but I've been busy.

    If not the fix maybe we need to meet up.

    Phil
     
  8. Philip Ellerbroek

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    Forum,

    Per Brad, I switched out the original roll servo for a brand new FF servo. Here's the flight...



    OR direct link: http://vimeo.com/58676208

    The only mod's I have done are replace half of the 6 month old red o-rings on each dampener with new blue o-rings. Temps are 65degrees F. Wind 1-2 mph. Roll radian gain at 135. Camera was balanced 3 weeks ago, but may need rebalancing after replacing servo. Servo bands appropriately tight and without slack. Shoots a 5d mark 3 with 28mm. FYI, using 3 axis Gimbal.

    Primary issue before was a roll shake or what otherwise looked like a delayed correction in the roll radian servo. In a video, you would see the horizon correct and level out but in a delayed manner or timeframe. This would cause a horizon twitch or roll. This was seen mainly when moving left then back towards a right bank roll, or vice versa, even in none aggressive movements. What you can't see in this video is my aggressive rocking left to right at certain times. On the video it rolls, but no where near as bad as it was. When flying one would never be this aggressive during filming purposes.

    I am curious about the vibrations at the 1:45 mark.....

    I would say this greatly improved the video, almost to the point of the problem being eliminated, leaving only minor tweak and adjustments needed. These adjustments would include double checking the camera balance, perhaps all new o-rings, stiffer gimbal plate, Gyro settings adjusted as well, particularly Gyro D (plan to try settings 12-17 per Adam).

    Current Flight settings - MK TOOL and Gyro Settings:
    P - 100
    I - 120
    D- 18
    YAW P - 100
    YAW I - 120

    Dynamic Stability - 70
    ACC/GYRO FAKTOR - 27
    ACC/GYRO Comp - 32
    Main i - 16
    Drift Comp - 0
    Gyro Stability - 6
    Motor Smooth - 0

    Phil
     
    Rex D Peters likes this.
  9. Gary Haynes

    Gary Haynes Administrator
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    Phil perhaps the vibrations are prop wash. Worst vibrations always seem to be in hover or vertical descents due to the dirty air from the props.
     
  10. Janne Hoglund

    Janne Hoglund Member

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    Yes, did this on two smaller ships and it made all the differense!
     

    Attached Files:

  11. kjetil tønnesen

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    her is the video:
     
  12. Brad McGiveron

    Brad McGiveron Active Member

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    Looks pretty good. Clearly some vibrations taken away with the steadyshot but the roll looks not bad at all.
     
  13. Philip Ellerbroek

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    Forum,

    Here was the BEFORE I changed the roll servo. Watch the shadow compared to the video. You will see the copter roll but there is a latency or lag before the horizon adjusts. This is the "roll twitch" I was speaking of....

    https://www.dropbox.com/s/yq17pqccgjy369q/Twitch.mov

    Phil
     
  14. Josh Lambeth

    Josh Lambeth Well-Known Member

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    So Phil, It sounds like it was a roll servo issue? Nothing else changed except for that?

    BTW I can't see your video in the post above. It says nothing is available.

    Josh
     
  15. Philip Ellerbroek

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    Josh,

    Opps!

    Try this now:

    Password: roll1

    Yeah it looks like the servo greatly cleared things up. Whats your next steps/plans? You going to servo swap or try an all new servo?

    Phil
     
  16. Brad McGiveron

    Brad McGiveron Active Member

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    Is this the improved shot? or the way it was before?
     
  17. Philip Ellerbroek

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    After servo swap. I have some before's I can post later.

    Thoughts?

    Phil
     
  18. kjetil tønnesen

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    i see you use 135 on gain
    try around 125 and see how it goes
     
  19. Brad McGiveron

    Brad McGiveron Active Member

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    There are less micro jitters which is better for sure.
    That big lag/wobble on the roll still seems there every time you go sideways and it has to counteract. It does it not smooth at all with a big wobble, otherwise its smoother.
     
  20. Philip Ellerbroek

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    Brad

    Yes, that roll wobble is what I can't seem to fix. Only other thing would be stiffer gimbal plate. Otherwise I have new blue orings on. I can't see how a stiffer gimbal plate would fix this.

    Any other thoughts since I know I have a new servo with realistic radian gains, tight bands and a balance camera?

    Phil
     

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