Do you use all the rubber ring dampeners with Radians?

Discussion in 'Radian' started by Chris Newman, Oct 10, 2012.

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Do you use all the ring dampers with the radian?

  1. Yes- Stiff as possible

    88.2%
  2. No- Loosey goosey is how I choosey

    11.8%
  1. Chris Newman

    Chris Newman Member

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    I'm curious to see if using all the slots for the dampeners is the way to go. How is your cinestar set up with Radians?
     
  2. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Im using all 6 on my gimbal. Im using 4 stiff black o-rings from Tabb and 2 red ones in the middle. So far I still seem to be getting an odd bounce that I can't make go away! :(

    Josh
     
  3. Tabb Firchau

    Tabb Firchau Administrator
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    I use the stiffest setup I can that will not produce any vibrations or jello in the footage. Vibration isolation is a complex task. We have to isolate all frequencies of the prop vibration that might ruin the footage but also not allow the mount to 'swing' around and degrade the footage. This task gets even more difficult when we put a stabilization system on the mount (like the Radian) as it can create a feedback loop with the isolator.

    The problem is we have 2 competing interests. The Radian would prefer the stiffest setup possible, while the camera prefers a relatively soft mounting system to kill as much vibration as possible.

    Hope that helps

    Tabb
     
  4. Chris Newman

    Chris Newman Member

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    Thanks Josh and Tabb for your responses. Incredible work Tabb btw!! My camera op are I absolutely loving the independence and freedom that the radians give.
    Tabb, what dampener setup do you use on your heli. What colors?
    Thanks in advance!
     
  5. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Chris,

    I use red o-rings, with all o-rings installed. This is on an octo carrying usually an FS-100.

    Glad you are enjoying the products! We love creating them!

    Tabb
     
  6. Sedric "Zellevision" Sari

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    All original, cs6, wood 14X5 props, with 360, radians and sony cx730. All rings in place, no changes. Superb stabilization, no jello or vibrations, just shoot and put in avid for edit, voila :). Sounds to me that cs8 gimbal is too stiff with four arms/dampners for cameras around ~700gr. Better for heavy setups like 1000gr+ ?!
    Did a job yesterday for swedish tv, and it was windy, like 6m/s and gusts up to 12... and problems to keep the copter "alive" :). When I look at the clips, theres nothing, like a steadycam in the air, and I do operate steadycams too! ;)
     
  7. Kari Ylitalo

    Kari Ylitalo Member

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    I would love to see a raw footage, can you share a small clip in 12m gusts. I have very similar setup with yours and get a problems with jitter/bouncing mount or too slow response. Also what flight controller you're using? I want that one what ever it is if it needs to be kept alive in 12m gusts.
     
  8. Josh Lambeth

    Josh Lambeth Well-Known Member

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    KariY, I too have this issue of bouncing still... I can't for the life of me get rid of it... Im almost ready to mount the gimbal hard (no O-Rings) to the copter to see if that works...

    Josh
     
  9. Kari Ylitalo

    Kari Ylitalo Member

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    I have tried lately combo where i had only 1 red ring at the both ends of damper + silicone gel block between them and i get slightly better results, still bouncy though but noticeable less than if all red rings are in use.

    But i think our solution might be in some kind of damper, which is soft only in horizontal axis but very stiff in vertical axis. Vibrations from motors and props are mainly if not only horizontal but our problem with bouncing is mainly vertical softness. All ideas of this kind of dampening system are very welcome.

    Kari
     
  10. John Gore

    John Gore Member

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    Is this for 3-axis gimbal I take it?

    What is the total weight of Camera + lens ?

    Tks
     
  11. John Gore

    John Gore Member

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    Thanks Kari, this is exactly the problem I have too, simply calling it "bottoming out" myself, but in fact it is bottoming out on the oposite direction... i.e. vertically (as you explained).

    I have had quite a bit of success so far trying memory foam, jammed in above the vibration isolators. This slows down the previously "free swinging to sudden jolt and bottoming out", but has the side effect of transferring too much vibrations (bypassing the vibration isolation system (red o-rings). However, this was just a first test, and I plan to test further, and will share results.

    So far I have tested:
    -- all 6 red o-rings, plus 15mm thick memory foam -> introduced some jello (7D + 10-22mm non stabilised lens)
    -- same as above, but added 2x 3mm washers (reduce compression of the memory foam) to the existing 10mm spacers I used to mount each vibration damper -> almost no jello, but still some vibrations.
    -- next, thinking of adding 2 more washers, and removing 2 red o-rings. Will only have time in a few days time though.

    Note: I am using 2 axis gimbal, so it will be lighter than 3 axis which many of you are using.

    (PS: I use the 7D for stills and aerial 360 panoramas, not for video, but use the cx760 for video. Ideally will like to have the setup as perfect as possible for both, but weight is about 800g difference, so will be happy to give priority to video on cx760, and have the setup a bit too soft for the 7D.)
     
  12. Joe Azzarelli

    Joe Azzarelli Active Member

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    I am having good luck with the mod shown below. The zip straps add some restriction to horizontal movement as well as stiffening.

    (Note: Your mileage may vary.)

    Joe Azzarelli

    isolatorModv2.jpg
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmmm. The decaf coffee hasn't kicked in yet this morning, Joe. It took me 20 seconds to figure out what you'd done -- the black cable tie disappears nicely against the carbon fibre so you've got a good "stealth" modification there.

    How tight did you pull that cable tie?

    Andy.
     
  14. Joe Azzarelli

    Joe Azzarelli Active Member

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    As tight as reasonably possible. You have to use two connected small ( 4" ) straps, unless you have available the very narrow width in longer length.

    Joe
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    In the USA, there are some 8" long, so-called "miniature cable ties." You can see them on the bottom of this page.
    That's obviously not the only vendor, but I had to search around before I realized that "miniature" really meant "narrow." :)

    Andy.
     
  16. John Gore

    John Gore Member

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    Nice idea. Getting a bunch of things ready to try. This looks like a simple mod to test. Tks for sharing!
     
  17. Shaun Stanton

    Shaun Stanton Active Member

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    My vote would be middle ground. I purchased the 3 axis system, I like its modularity and compactness in the design. However we flew it today and got a nasty panning jitter. We were using a lightweight Cannon Vixia as our test camera. I figured it was do to the gimbal inertia pulling on the vibration dampeners, and causing the control system to get confused and getting "Robot" induced oscillation. After reading these posts it confirmed my assumption. I did not seem to get a bad jitter on the roll compensation. All though I was not being real aggressive with the a/c I put it to 250 feet and stuck it on hold modes. Tonight in my lab I affixed some two rubber grommets on two of the isolation dampeners standoffs where the gimbal plate meets. This stiffened that area considerably preventing roatation movement of the plate about the vertical axis. I benched tested it tonight and the gimbal is smooth as silk now. The unknowns are how much high frequency dampening did I loose by making it stiff. I tried to meet middle ground by only stiffening two dampeners and leaving the adjacent ones loose. We will be flying tomorrow to test this theory out.

    It seems like a workable solution might be to use something less stiff but also preventing too loose of a movement as well.
     
  18. Joe Azzarelli

    Joe Azzarelli Active Member

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    Shaun
    I know it is somewhat academic, but make sure the pan belt is TIGHT and also check the bolt attaching the pulley to the servo. The mass that the little servo needs to accelerate and decelerate is significant and any latency from when the radian says 'stop' and when it senses the stop occurred sends it into rubber-band mode. Play in the belt drive contributes to this and some of is definitely coming from the lateral movement of the vibration isolators.

    The trick becomes how to stop or dampen lateral motion but retain the vibration isolation qualities of the isolators. This is what my post #14 on this thread attempts to accomplish. My results are 'improved but not perfect'. I agree you may lose some hf dampening with stiffer o-rings, how much is dependent on the weight of the gimbal + camera.

    Please let us know any outcomes, good or bad, from your testing. Collectively we should be able to solve these issues.

    Joe Azzarelli
     
  19. Shaun Stanton

    Shaun Stanton Active Member

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    Joe

    We flew today testing our mod and we apparently made it too stiff and got what you said. We eliminated all the panning jitter, but we now have jello footage. It seems with the zip-ties the isolation dampers still seem loose, but I will give a shot later on the bench test. I did see that there was a firmware update, I did not update the system after getting it so I may need to do this as well and see what we get.

    I will undo my mod maybe try yours out. I did stiffen the drive belt, as I can see how that can cause a delay and induce oscillation as well. It almost seems to me that the work around is some dampening constant to the spring coefficient of the isolation to allow the isolation to still move in a fashion that will dampen motor vibe but at the same time not adding a negative feedback to the system. I am thinking about wrapping the standoffs with some packing foam and see what that does. I hope we can figure it out, obviously this will be super important.
     
  20. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I just did 2 more flights using Joe's method. So far it is the best fix. Footage has never been as smooth as it was tonight. I did 2 flights, one with a lower roll gain then the second i bumped it from 120 to 145 and it is even smoother. Video is rendering now so you can take a look.

    Josh
     

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