I in working out forces in a real mechanism

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SUMMARY

The discussion focuses on addressing the wobble issue in a mechanism controlling multiple assemblies in the X, Y, and Z directions. The team identified that the wobble is caused by inertial torque and inadequate restraint, proposing solutions such as adding outboard vertical restraints, adjusting the pivot position, incorporating dampers, and using scheduled starts for rapid movements. The discussion emphasizes the need for force vector diagrams and torque diagrams to analyze the forces acting on the mechanism and validate the proposed solutions.

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MeesterDave
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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.
75dc1de358.jpg

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!
 
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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:
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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