Unstable roll axis on video footage

Discussion in 'Radian' started by Björn Smith, Oct 27, 2013.

  1. Björn Smith

    Björn Smith New Member

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    Hi all!

    I'm having big difficulties obtaining reasonable stable video footage with my CS6. I've read most threads here related to the problem and made many different test but without any major success. This is my setup:

    bild-1.JPG
    - 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)

    I realize the roll axis stability issue could be caused by either a "nervous hexacopter" or improper adjusted gimbal (or maybe both). Therefore I mounted a 2:nd camera (GoPro) hard to the frame and created a synchronized video with the content from both cameras. bild.JPG

    By watching the video one can see that after 1:20 it seems that the Radian roll gyro is twitching a lot. There was a moderate to light with during this flight.

    My cheap old DJI FlameWeel with GoPro gives better video footage :-(

    Could anyone please give me a clue of where I should start!?
    Many thanks in advance for any kind of help!
     
  2. Karl b

    Karl b New Member

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    Hi
    Did you manage to solve this problem as I'm having similar problems on a hex I have built
    Thanks in advance
     
  3. Björn Smith

    Björn Smith New Member

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    No, not really. I think it will be very difficult to get a much smoother footage. At least when it's a bit windy. I've decided to convert my gimbal to brushless with some high-end components from brushlessgimbals.com. Unfortunately I will not be able to build and test the new gimbal until beginning of January.
     
  4. Gary Shainberg

    Gary Shainberg New Member

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    Guys

    I have been offered some great support from Gary via this forum but have been a little tied up to get all the infer to him to continue which I hope to do this week, however, I am flying a HEX with a 3 axis CS3 all with Radians and have spent hours on this and still have had bad results, however, although I would like to try and get it working with Gary's help, I have decided to go brushless with AlexMos control which I hope to convert his week.
     
  5. Gary Haynes

    Gary Haynes Administrator
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    Björn there are multiple threads on the forum about how to both balance and then go through the steps to dial in the appropriate settings. The key is to be very methodical about testing and test each axis independently. There are no short cuts if you want to get the best performance out of the Radians. And you CAN dial them for great footage. You may still need to use some warp stabilizer but the last stuff I was shooting with Radians, warp was down to 3-5% setting.
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    Bjorn,
    I have a couple questions about your setup.
    1. there seems to be something mounted underneath the camera on the horizontal boom (it looks red). What is that?
    2. the cable coming from the GH3 (shutter release?)...where is that going?
    3. it looks like you're using all red vibration isolators...i use a mix of 4 red and 2 blue with my GH3
    Any or all of these could lead to problems with both balancing and with extraneous things causing twitching.
    Steve
     
  7. Karl b

    Karl b New Member

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    I use brushless gimbals that I make in my workshop the results are amazing, this video was shot in 22mph winds on my 650mm hex with naza. For me getting smooth video is not what I'm worried about, I just want a stable platform to bolt my camera to. My 800mm hex with wookong seems to behave like Bjorns, which concerns me slightly as it seems too easy for an unstable aircraft to become overwhelmed by the wind. It is usable but I just don't feel as confident as I do with the 650mm
     
  8. Björn Smith

    Björn Smith New Member

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    Hi Steve!
    The red-ish thing under the camera is the HDMI converter for the video down-link.
    The shutter trigger is one from Gentles Limited connected to one receiver aux channel.
    Your comment on the vibration isolation is interesting. Yes, they are all red rings but I have a pack of blue rings as well that I never tried. The reson for this is that I was recommended by an experienced person to stay with all red ring for cameras up to 1.5 kg. I'll try to mix in some blue rings like you suggested to see if it gets more stable.

    Many thanks for your input!
     
  9. Björn Smith

    Björn Smith New Member

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    Hi Karl!

    Interesting that you have the very same experience as I have. I fly my reliable and predictable FlameWheel 650 and I feel comfortable and safe to fly. However, with my super expensive (in my opinion) CS6 I get a bit nervous when it suddenly starts wobbling more than expected during flight. In my opinion, it should be possible to get a large 1100 mm CS6 as stable or even more stable than a DJI FlameWheel of 650 mm. Both have Wookong M with latest firmware and I've carefully tested with gains within a large range. :(
     

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