Strong Vibrations

Discussion in 'ALTA' started by Ricardo Perret, Nov 4, 2015.

  1. Dave King

    Dave King Well-Known Member

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    I used black dampeners for everything as well when I had the Cinestar. However I believe that you can't compare the black o-rings on the Cinestar to the black O rings on the Alta because the Alta's vibration dampening is stiffer no matter which O rings you use. I have 2 M5's one for the Canon 5D and one for the Sony A7S and the A7S needs a lot less for tuning numbers than the 5D.
     
  2. Ricardo Perret

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    Hy @ all

    I run my Alta with M5 and A7s and have alsoe shaking issues.... Sometime less and sometime More Vibrations (more ore less wind)
    But im thinking, my Alta has pretty Much vibrations on the Chassis with standard Settings. As attached a Screenshot from my APP Monitor.
    Are this Vibrations acceptable ore what should be Okay?
     

    Attached Files:

  3. Cam Batten

    Cam Batten Member

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    @ Dave and Ricardo,

    Could you each please post your M5 A7s Settings. I'd be interested in comparing the two, and dave if you have any test footage?

    Pan Gain
    Roll Gain
    Tilt Gain
    Gyro Filter
    Output Filter
    Pan Hold Strength
    Roll Hold Strength
    Tilt Hold Strength
     
  4. Ricardo Perret

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    Hy Cam, here my Settings with my best but not perfect Result:

    Pan Stiffness 36
    Roll Stiffness 51
    Tilt Stiffness 19
    Gyro Filter 1
    Output Filter 1
    Pan Hold Strength 44
    Roll Hold Strength 13
    Tilt Hold Strength 16

    Best Regards
     
  5. Cam Batten

    Cam Batten Member

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    Thanks Ricardo. Interesting to see those Filter output's so low! What lens are you flying?
     
  6. Ricardo Perret

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    Hey Cam

    I have ,mount the Sony 28mm lens with the ultra Wide converter to 24mm...
     
  7. Dave King

    Dave King Well-Known Member

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    I had time to play with it a lot today and I see what the issue is but I don't know exactly what the fix is but I do know what is going on. When I posted last I tested with no batteries on the Alta which was a mistake because as soon as I added batteries the vibrations are there and very violently I must say.

    The issue is the pan motor with the Alta when the MOVI is on the ground and set to ground mode (middle position) in airborne mode but it only an issue if you have the batteries up on the alta. I run 2 10,000 mah Tattu batteries and nothing else to compare to see if its as bad with lighter batteries.

    This would be a none issue if we could have separate tunes for the ground/air modes but we can't so it has to be all or nothing and you halve to set the main air tune to have extremely low stiffness setings to get it to not vibrate on the ground.

    I have 2 M5 Movi's one with the Canon 5D mark II 24 mm prime lens and one with the Sony A7s and 24mm prime lens. It does this on both gimbals so the issue is not related to just the Sony camera combination.

    Here's my normal settings for tuning the Sony A7S with the copter floating in the air.
    Stiffness settings
    Pan 130
    Roll 58
    Tilt 19
    All 3 motor hold strengths are factory settings of 8.
    Gyro filter 3 (factory setting)
    output filter 3 (factory setting)

    If the batteries are off the copter, there is no vibration when either MOVI is connected to the Alta in the ground mode (middle switch). But if the batteries are on the copter the Pan stiffness settings have to reduced all the way to 45 to have no vibrations.

    The only way around this issue is to have the movi motors killed and set to off (set the switch on the radio closest to you). Then switch to air mode when you take off. I normally don't like doing this the camera can get off balance easily especially if you are launching from an uneven surface. That's why I like the middle ground mode as you at least have roll motor power.

    In my opinion there's two fixes for this, allow for a separate ground tune or just have the pan motor with no stiffness or power setting in the ground position.

    I am going to send this as a support ticket to freefly.
     
  8. Howard Dapp

    Howard Dapp Active Member

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    Am I wrong but I thought the purpose of buying a professional grade complete, non-frankenstein system like Alta was to rid yourself of all the troubleshooting and tweaking one had to do with other hobby-grade systems? Now with the latest 'reported' unsolved death roll and crash it seems some things will never change regardless of the amount money you spend.
     
  9. Gary Haynes

    Gary Haynes Administrator
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    Dave everyone I know is starting in Kill mode on the ground and then switching on one off the ground. Single op I simply reach over to the other TX or MoVI controller and flip the switch while in a hover. If everything is balanced how does your camera become unbalanced when launching?
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

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    Same here. Works fine.
     
  11. Steve Maller

    Steve Maller UAV Grief Counselor

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    Yes you're wrong.
    ALTAs are in service all over the world and doing work every day.
    It isn't clear what happened to Adam's.
    Freefly have been very proactive in supporting us.
     
  12. Dave King

    Dave King Well-Known Member

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    Gary

    I recently flew with 2 others club members from Western PA and they had M5's using different frames and they also use the middle position for take off. If everyone is taking off in kill position what is the purpose of the middle ground position if you can't use it? Why was it implemented as a feature? If you can't use it you might as well use hand held mode.

    My M5's are as balanced you can possibly make them. I am probably more meticulous than most on the details of balancing not only the gimbals tilt and roll and pan balance plus the overall CG of the gimbal and copter. I take off quickly on takeoff just a force of habit. I"m not saying I have the throttle full up but I take off quicker than not. I guess I can slow down my take off's but if you take off from any uneven surface without the motors powered up and then the copters attitude changes to level off in flight it can generate enough side to side inertia that will force the camera to one side or another no matter how balanced the gimbal is. If I really have to work around it I could have the camera operator switch to air mode as soon as I spool up the motors because the M5 takes a little bit of time to start spinning but it would be nice to have the feature to use as it was intended. Hopefully it can be addressed in the tuning but if it can't it would be nice to add a bit of tuning features for the MOVI in airborne mode. That's all I am saying.

    As far as Howard's reply, I don't agree. I am in no way blaming the Alta for these issues. From everything that I experienced so far it is worth every penny to me as it is far superior than anything you can build. I have no regrets purchasing this machine In my opinion its not fair to criticize the Alta's reliability because of one isolated crash or because of this isolated issue related to the M5. There might be something else in the M5 tuning that I am not aware of. Yes you can setup separate tunes with the Alexmos for ground and take off but then I would be constantly battling with its own unique bugs. So not everything is black and white.
     
  13. Steve Maller

    Steve Maller UAV Grief Counselor

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    I use airborne mode for two-operator or stills, and handheld for one-operator video so i can use the majestic features.
     
  14. Dave King

    Dave King Well-Known Member

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    Thanks. Out of curiosity why use airborne mode if you can't use ground mode and just use kill mode for the ground?
     
  15. Ben Ruffell

    Ben Ruffell Active Member

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    I keep it in kill mode while my pilot spools up.

    Then, as the downforce is generated, the gimbal and camera can be blown around a little bit, so I flick it to the centre position. (Airbourne mode).

    This holds the camera still and stops it floating around.

    As he lifts off, I flick it to manual.

    When landing, I leave it in the central position and flick it to kill as he touches down.
     
  16. Stefan Helborg

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    Just to be absolutely sure of what to think. I use MOVI controller.

    Airborne = D = Dual mode
    Handheld = M = Majestic mode
    Kill = K = Kill mode

    right?
     
  17. Bryan Edmonds

    Bryan Edmonds Chief MōVI Whisperer

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    The difference between Airborne and Handheld is the function of the middle position on the mode switch.

    Handheld = Majestic Pan
    Airborne = Parked

    Parked mode stops the pan motor in what ever position it is at, and brings the tilt back up to pointing straight ahead. The roll will stay at 90 degrees to the vertical pan frame/tube (with the GCU/MCU mounted on it).
     
  18. Dave King

    Dave King Well-Known Member

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    All I received this email from Freefly support yesterday.

    Thank you for contacting Freefly Technical Support. Thank you for the detailed explanation of the issue you are experiencing. I was able to replicate the symptoms when the MōVI is parked on the ALTA. It actually has nothing to do with the MōVI and everything to do with the design of the suspension on the ALTA.

    The osculations you are experiencing are the cage that the Toad is mounted to, twisting slightly back and forth, flexing in resonance with the pan motor. I have shown this to our engineers and they are confident a firmware update can address this from the MōVI end.

    Until it can be sorted out with an update, I recommend continuing to take off in Kill mode and switching to parked, or dual as soon as you are off the ground. A lot of our pilots fly in Handheld mode and do this as a practice without issue.
     

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