question of robustness

Discussion in 'MōVI M10' started by Brett Harrison, Sep 6, 2013.

  1. Brett Harrison

    Brett Harrison Active Member

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    I would like to know what sort of limit there is to velocity counteracting the motors, i.e. bumps in the road on a car rig or a sudden change in orientation.

    The application I have in mind is some off-road car rigging, or off-road motor bike rigging. I see that it's been used on horseback! so I am thinking it should be okay but I'd like to know to what degree you need to baby it.
     
  2. Brad Meier

    Brad Meier Active Member
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    The thing you have to remember is that MoVI itself does not take out translation. So mounting directly to off-road car would of course have translation issues if your moving fast over a bumpy road. At that point it's all about how you mount it. The horse shots were handheld, I've done shots from a car on bumpy roads handheld... But in those cases your arm is handling the translation motion while the MoVI takes care of roll, tilt, and pan.

    Its all about vibration. Too much... your not getting perfect footage. It's a very robust piece of equipment. Also remember its a very precise piece of equipment.
     
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  3. Brett Harrison

    Brett Harrison Active Member

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    Thanks for the clarification Brad. I understand that it doesn't take care of translation, but rotation, I just wonder where the threshold is of acceleration that can't be factored or counteracted per 100th of a second, if that's the correct metric.

    edit: for example, the lens is 100mm, the car goes over a slight bump, but the MoVI tries to smooth that out because the movement is below a threshold of rotation of the rig that counts as a command to pan camera (up down in this case) however if the bump is sharp enough would that overcome the MoVI's ability to smooth that out.

    Also, can bumps if they are rapid enough cause wear on the motors?
     
  4. Brad Meier

    Brad Meier Active Member
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    Ive personally done a few tests with quick accelerations in a car and attached to a Cinestar multirotor. There were no issues with either. The Cinestar accelerates much faster than a car would.
     
  5. Brett Harrison

    Brett Harrison Active Member

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    I mean acceleration caused from a bump in the road, i.e. vertical acceleration, rather than horizontal or lateral. Like if the car hit a pothole for example.
     
  6. Brad Meier

    Brad Meier Active Member
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    No different, except a pothole would be 95% translation motion.
     
  7. Tabb Firchau

    Tabb Firchau Administrator
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    Brett, Situations like this get very tricky for stabilized platforms. A huge instantaneous shock like a pothole in the road can generate HUGE accelerations. In order for any stabilized platform to cope well it would need to be precisely balanced. Theoretically if you were able to balance the MoVI perfectly then all you would see is translation. In practice you can't balance it perfectly (unless you are willing to spend 3 days on the task) so you will be able to achieve some level of disturbance rejection which correlates to the quality of balancing and the stiffness settings in the GUI.

    I don't have an exact figure on what kind of disturbance rejection you will achieve as it is very hard to quantify since the payload, disturbance amplitude, and frequency are all unknowns.

    Hope that helps!

    Tabb
     
  8. Brett Harrison

    Brett Harrison Active Member

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    Thanks Tabb that's what I was getting at. : )
     

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