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I need help in working out forces in a real mechanism

  1. Jul 26, 2016 #1
    I have a mechanism that controls the movements of multiple assemblies in the X Y and Z directions.
    The mechanism has been built and suffers from a wobble on a fast X travel. We have a few suggested solutions but it would obviously be a good idea to get some calculation to help prove a solution.
    We all (a small team of 4) are scratching our heads and trying to recall force vector diags and torque diags.
    the Yellow dot is the COG
    The orange squares represent rails and carriages stopping (ideally) X and Y movement
    The orange square in the middle is a linear cam that is used to raise and lower the assembly that is driven towards the viewer. Consequently all the weight is on this cam and follower and pivots about the cam.
    hence the wobble shown by the red arrows.

    Im looking for a way of representing the forces acting on this and so use the same method to show forces on proposed solutions.

    Thanks in advance!
  2. jcsd
  3. Jul 26, 2016 #2


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    Problem : Inertial torque + inadequate restraint .

    Solution : Add outboard vertical restraint + move notional pivot position + add dampers + use scheduled start for rapid movements
    Last edited: Jul 26, 2016
  4. Jul 26, 2016 #3


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    Do you have a better CAD view which shows more about your cam and linear rails? What kind of linear rails are they, and can you buy ones with higher moment stiffness?
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