Wobbling/Shaking M15 on ALTA6

Discussion in 'MōVI MR' started by Tim Hoef, Oct 8, 2016.

  1. Tim Hoef

    Tim Hoef New Member

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    Hi Guys,

    we've got some problems with our MoVi M15 on a ALTA 6. There is some wobbling / shaking on each axis - no vibrations. We've tried to increase the stiffness, but it don't solved the main problem and added some vibrations. The gimbal is carrying a BlackMagic MicroCamera in the video. Same problem with Alexa Mini and A7S.



    PW: movim15

    Current setup (for BMMC):
    Tilt Stiffness: 32
    Roll Stiffness: 70
    Pan Stiffness: 94
    Tilt Hold: 12
    Roll Hold: 12
    Pan Hold: 14
    Gyro Filter: 5
    Output Filter: 1
    Tilt Filter: 3
    Roll Filter: 3
    Pan Filter: 10
    Jolt Reaction: 2
    Heading Assist: GPS

    Teal O-Rings on ALTA.

    Has anyone an idea?

    Many thanks in advance!
     
  2. Ozkan Erden

    Ozkan Erden Distributor

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    Hi Tim,

    Can you adjust these settings:

    Gyro Filter to 2

    And set the stiffness again. Stiffness settings should be higher now and this should help.
     
  3. Mike Reid

    Mike Reid Member

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    Tim, what I have been doing since the newest update is:

    -Suspend the Alta and run auto tune
    - once it's done I will use my movie controller to run the tilt and roll through full ROM, if I get any vibrations starting I will adjust each axis' filter slightly to see if it fixes it. If not, I will do my gyro and output filters.
    - after that is settled I will run through the ROM again, then try giving each axis a good hard tap to see if it brings any vibrations, or if it immediately settles.

    Doing this I have been able to get pin sharp photos on the new hasselblad h6d on a 100mm with as low as 1/125 of a second.

    You may also need to do a little bit of tuning on the Alta. If you have your setting modified, do a reset and work out each node individually. I start in position hold with stock values. If I have any shakes I will drop my stiffness down by 2, then retest. If I still have shakes after dropping by 3 I will take a couple off of hold strength until it is perfect. Continue on to height mode, then attitude.

    Also check your props to make sure you don't have any z axis play (up/down). Hold them at the hub and move each side individually. If you have play, adjust by 1/8-1/4 turn, they tighten up quickly. Don't over tighten because that can be just as bad as too loose. It's a fine line, and you need to keep on top of it every 10-15 flights, but it will make a difference. Also, aero landing gear. I was skeptical and didn't want to spend the extra $, but it does make a difference.

    Also, when flying light cameras I find adding a bit of extra weight by using shaft collars (I think I stole that from Dave King maybe) is helpful.

    Thanks all I can think of
     
  4. Derek Cooper

    Derek Cooper Active Member

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    I'm not familiar with the MicroCamera, but based on its name it does sound *small* and light. The A7S is definitely light.

    The M15 likely doesn't find either of these payloads ideal and are probably better served by a Movi rated for their weight - like the M5. We have found that flying the M15 with lighter loads typically means adding weight.

    The Alexa Mini should be fine though, so it's likely a filter setting so follow Mike's advice and let us know how you get on with it.
     
  5. Tim Hoef

    Tim Hoef New Member

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    Thank you, for the answers.

    We set the Gyro Filter to 2. Now its possible to reach much higher stiffnesses.

    Tilt Stiffness: 70 (Output Filter 1)
    Roll Stiffness: 145 (Output Filter 2)
    Pan Stiffness: 230 (Output Filter 16)

    Also we take the red O-Rings. It looks much better now, but on higher focal lengths it's still not as smooth as we had expected.

    Here is a clip with the new settings (focal lengths 70mm and 24mm):



    PW: movim15

    Do you think this is the best result we can get without adding extra weight?

    Mike, what do you mean with "ROM"?
     
  6. Derek Cooper

    Derek Cooper Active Member

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    Where is the problem in that video?
     
  7. Mike Reid

    Mike Reid Member

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    Range of motion, sorry for the abbreviation!
     
  8. Mike Reid

    Mike Reid Member

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    That looks pretty good, but try testing it at speed, do some ascents, descents, push it hard and see how it reacts, see if there are and shakes or vibrations that pop up from those tests. I like to tune to the hardest conditions that I will fly it in, that way when you are being nicer to the rig it will be just fine.
     

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