Smooth video

Discussion in 'Cinestar 6' started by Laza Randria, Jul 2, 2013.

  1. Laza Randria

    Laza Randria New Member

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    Hi everybody,
    I fly a CS6 Wookong with 2axis radian with a sony cx760. My radian gain for roll and tilt are at 100%, deadband 15%. My Futaba T8fg with expo -30%, I think that my multicopter is still too nervous for video, and I still have some small roll shake. basic/atti: pitch 180%/130% roll 180/130 yaw 130 vertical 100. And for "gain advanced" I pitch&roll 100 / Vertical100% --- v.damping 100/100 ---disturbed gain 100%

    The question is where should I begin: to remove Expo in the futaba like -60% or change the gain in the wookong or for the CX760 100% gain in the radian gain is too much.

    Greetings from Madagascar
     
    Martin Larsen likes this.
  2. Janne Hoglund

    Janne Hoglund Member

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    Well first of all you must be sure if it is the copter or the gimbal that is causing the vibrations.
    Try flying with both the camera stab and the Radians off.
     
  3. Björn Smith

    Björn Smith New Member

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    Hi Laza!

    I'm "in the same boat" as you. Have you managed to get it stable enough since July? I find my CS6 all too unstable for video. My old DJI Flamewheel 550 gives more stable video!!! My setup is:

    - CS6 with 500 mm booms, 2-axis gimbal with Radian gyros
    - Wookong M with gains set to 175, 125, 175, 75 for P, R, Y, V and 65, 65 for attitude
    - Motor idle speed set to maximum
    - Motors are standard (came with the frame) 3328 700 rpm/V
    - 14x4.7 APC propellers well balanced
    - ESC are Maytech 45A opto with Simon K firmware
    - Batteries are 2x6000 mAh 4S
    - Futaba T8FG radio, all S-bus connected
    - Radian gains 100%, 100%
    - Camera weight 930 gr (Panasonic GH3)
    - AUW (total weight) 5400 gr
    - Vibration damping is standard (all red rings)

    After several tests flying with two video cameras, one on gimbal and one fixed to frame, and synchronizing the two videos shows the following: The fixed camera is the upper and the one on gimbal the lower.

    Further indoor tests with the CS6 hanging from two strings shows that the 2-axis gimbal with Radian gyros cannot absorb the roll axis motions like the once during flight. My conclusion is that my CS6 frame (and not he gimbal) is all too nervous and I'm really out of ideas how to get it more stable.

    Right now I'm a bit desperate and would really appreciate any advice that would make my CS6 acceptably stable for video.

    Many thanks in advance for any kind of help!
     
  4. Dave King

    Dave King Well-Known Member

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    Sounds like the camera isn't balanced good enough on the roll axis. Here's a video I made to help
     
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  5. Björn Smith

    Björn Smith New Member

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    Thank you Dave for very good and clear instructions in your video. I have balanced it but not as careful as you describe. I'll do it again and more carefully as you describe and test again. Many thanks :)!
     
  6. Graydon Tranquilla

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    I had similar problems with a custom designed 800mm Hex using 22pole 570kv motors. Once I switched up to 22pole 420kv motors these issues disappeared. Keep in mind that I power these with parallel 6S - 5000 mAH batteries and use 15 x 5.5 carbon fiber props. I chose to 420 kv motors not only because of efficiency gains but also because they provided the extra torque needed to respond to FC control faster. And PID loop control for pitch and roll is only as good as the ability of the motors to respond fast. Higher torque and less speed range give you faster response time.
     
  7. kjetil tønnesen

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    Hello
    If you use the radians then be wear off that system is not perfect and you will allways have a bitt trouble with roll
    If you want perfeck steady film rigth from your camera sony cx760 go for brushless gimble.
    However the radian can make good video too but not perfect .make sure everthing is balanced and finetune the cs6 and gimble

    Thanks
     
  8. Brad McGiveron

    Brad McGiveron Active Member

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    What Kjetil said:)


    Björn, you can get somewhat better results with many hours of messing around with balance/tricks and other things with the Radians and servos but it will never be perfect or not need some post stabilization to be super smooth.
    Your currently setup and how it is flying in that clip would be absolutely smooth out the camera with a brushless setup. It sucks I know, but that's the reality of new tech vs old tech.

    So ya if you are staying with Radians and servos just get your balance and all the suggestions from the others sorted. Just be aware of the limitations.
     
  9. Björn Smith

    Björn Smith New Member

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    Thank you Kjetil and Brad for your input!
    Yes, I've looked around a bit on the net for brushless gimbals. However, Mövi is beyond my budget so I have looked for CS 2-axis gimbal conversion kits. Do you know if there is a good conversion kit or do I have to build it myself? What gyro and motors should I go for?

    Thans again! :)
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

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    If you want to DIY, BrushlessGimbals.com has some good quality parts to mod a Freefly gimbal (2-axis or 3-axis) and they have really good support.
     
  11. Graydon Tranquilla

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    I have successfully installed the following on my CS8 and I use the brushlessGimbals.com Alexmos 2 axis BGC.
    And both the 2 axis BGC and 2 axis gimbal can be upgraded or purchased as 3 axis.... here are some details.
    http://www.rctimer.com/product_912.html
    http://www.rctimer.com/product_976.html
    A custom G10 interface plates was created so I could use the existing camera mounting holes in the CS8 camera anti-vibe attachment.
     

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  12. kjetil tønnesen

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    I woud go for alexmos 3axis
    if you want to bulid one you shoud go for ipower 150-180 turn
     
  13. Shaun Stanton

    Shaun Stanton Active Member

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    Steve are you getting good results with your BGC gimbal in flight?
     
  14. Steve Maller

    Steve Maller UAV Grief Counselor

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    haven't flown it yet. got sidetracked. radian rig's working great. :)
     

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