Tuning issue

Discussion in 'MōVI M10' started by alex ryan, Sep 18, 2016.

  1. alex ryan

    alex ryan Member

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    A reoccurring issue I've been having with my M10 is that if I tune it with the radio Tx on and connected to the Movi I am able to get much higher stiffness settings. And when the radio Tx is on everything is working beautifully - The gimbal performs well and there are no oscillations, but when I turn the radio off and the M10 reverts to majestic mode I get severe oscillations.

    This is a link to a video of the motor monitor in the app showing what happens when I turn off the radio. when I shot this video the M10 was suspended from my ALTA. I had just moved the alta around in all directions with no oscillations and based on previous flights the gimbal would be doing a good job in the air.

    https://www.dropbox.com/s/9d8qr7d7gf4fw9b/tuning issue.mov?dl=0

    I just updated to the new firmware and the issue seems to be attenuated slightly. The same thing still happens, but the oscillations aren't as severe.

    Any ideas why the M10 does this? I have posted about this before, but didn't get any answers as to why this happens so thought id ask again.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    How far away is the Tx when you're tuning the M10, Alex?
    If it's only a few feet away, try tuning with the Tx on, but 10 feet away and see if the effect still happens.
    I'm just wondering whether the Tx is injecting some kind of interference when it's close by that's messing with tuning.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  3. alex ryan

    alex ryan Member

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    Thanks Andy I will try that.

    Yes the tx is only a few feet away, but the thing is, the gimbal only oscillates when the tx is off.

    Are you saying that the tx may be causing interference during the tuning process that makes it so my stiffness levels are too high?

    The difference between the stiffness levels I am able to achieve with the tx on in comparison to when it's off is substantial, especially on the pan axis.

    I did notice after doing this test that one of the screws on the battery mounts was loose, so this may have been causing problems, but it's still interesting that the tx being on or off makes a difference and trying to understand why.
     
  4. alex ryan

    alex ryan Member

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    Could it be that the filter settings are creating the problem? I am countering the alleged tx interference with the filters and then when I switch the tx off the filters are not in the sweet spot any longer?
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Not sure whether the Tx will be causing interference, Alex -- so I was just suggesting you have the Tx on, but not so close, and then try tuning to see if you see the same problem.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  6. Graham Futerfas

    Graham Futerfas Well-Known Member

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    Just to clarify, Alex, is your Tx set to Majestic Mode when you're seeing this change? Or is it in Remote?
     
  7. alex ryan

    alex ryan Member

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    Yep will do, but theoretically should it make difference to the tuning when the tx is on or off?

    Also, a slightly unrelated question. Usually I tune the gimbal while hanging from the suspended Alta. I usually do this with the Alta resting on three chairs. But the other day it was raining and my studio doesn't have enough floor space to do this so I hung the Alta from a beam in the ceiling with a strap attached to the top handle of the Alta. It occurred to me that this probably isn't the best way to do it because it removes the vibration dampeners from the tuning equation. hoping you could enlighten me with your thoughts on this. If I am to hang the Alta to tune the gimbal again, wondering if you have any tips on how to hang it?
     
  8. alex ryan

    alex ryan Member

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    The tx is in remote. It has full control of the gimbal. The gimbal is set to airborne mode. Then when I switch the tx off the gimbal begins to oscillate.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Alex: I think the general rule is "Always tune it like you want to use it." So if you're going to be flying, then hang it using the main handle so the ALTA is "flying" -- then all the masses in motion are as they would be when airborne (absent slipstream and rotor wash, of course). I just use a Velcro piggin string to hold the ALTA for a C-stand with boom on it (and counter-balance, of course). I'm not sure whether everyone calls them piggin strings, so I mean one of these: https://www.bhphotovideo.com/c/product/65641-REG/Porta_Brace_PS_6_PS_6_6_Piggin_String.html

    Graham: Are you heading down the path that the MoVI should be in Majestic and then tuned in Majestic to avoid any sudden spasms in flight?

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  10. Graham Futerfas

    Graham Futerfas Well-Known Member

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    I'm not a flyer, so wouldn't know about that issue, but I'm trying to determine why the Movi tunes differently with the Transmitter on. Sounds like Remote\Majestic may be one possible culprit.
     
  11. alex ryan

    alex ryan Member

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    Right, well this is what I did, but if you are hanging the Alta from the main handle are you not effectively reversing the forces put on th vibration dampeners as compared to the conditions it would be in during flight?
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Well, apart from Airborne Mode, you really a "flyer" Graham -- it's just that your hands take the place of the copter! :)

    I agree with you. I need to experiment to see whether Autotune gives substantively different results depending on the Remote/Majestic setting. Certainly you will get very different results between "in repose on chairs" versus "dangling from the ceiling" because of the different masses in motion (aka "the legs cannot waggle when the MoVI's resting on'em!")

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
    Graham Futerfas likes this.
  13. Graham Futerfas

    Graham Futerfas Well-Known Member

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    Next time I'm set up, I can run a test on that too.

    And I'll just picture myself in a bird outfit with feathers next time I'm operating\flying my Movi LOL! :) You flyers have way more skills and things to worry about than us hand-operators.
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Indeed you are -- if the MoVI is suspended underneath an ALTA that is dangling from the ceiling, then the vibration isolators will be in in tension (the ALTA's lifting up, the weight of MoVI is pulling down), whereas if the MoVI MR is resting on the ground, it's going to be pushing up to support the ALTA thus compressing the vibration isolators.

    Andy.

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  15. alex ryan

    alex ryan Member

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    Just to clarify, the Alta is resting on the chairs. The gimbal is free to move and suspended from the Alta. But yes the chairs are locked in place from the weight of the Alta with the gimbal suspended from it.
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    There are some images that need to be left unseen, Graham. Hold the feathers! :)

    Flyers need to worry about flying the copter into something, surface residents need to worry about the trip'n'prat-fall. Flyer's tend to stand relatively still (in my case because I'm petrified!) :)

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  17. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmm. So how is the ALTA being supported by the chairs -- I may have misunderstood what you were saying Alex -- in which case I apologize -- are the ALTA booms resting on the chairs? In which case that's similar to flying but not quite the same as the booms are being held relatively immobile by the chairs -- in contrast to "dangle mode" where the whole kit and kaboodle is twistin' in the wind....

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  18. alex ryan

    alex ryan Member

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    Yes that is correct Andy. The Alta's booms are resting on the chairs, and the chairs are immobile, but the ALTA is supporting the weight of the MOVI, legs off the ground. I suspected dangling would give a more accurate simulation of the conditions the movi would be in during flight, but just had the thought that if I hang the alta using the main handle (which is connected to the vibration dampeners, not directly to the fuselage of the ALTA) the vibration dampeners aren't doing what they would be doing during flight (they are expanded from the weight of the ALTA rather than being compressed) so this may effect the tuning results (but it sounds like this may not be significant judging from your advice). I thought maybe a better way of achieving 'dangle mode' would be to hang the ALTA from the booms rather than the handle, but then I guess you would get less 'twist in the wind'.
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    It would be an interesting experiment to autotune with the ALTA in dangle-mode suspended by the handle, versus suspended by the booms. I've no idea what the resulting values would be. I'm side-tracked for the next few days, so please post on what you find if you get a chance to do that test!

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     

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