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Mating errors on Rod End Bearings in a Triangular Stewart Platform Design. Help needed!

Question asked by Jose González on Nov 18, 2016
Latest reply on Nov 23, 2016 by Jose González

Good morning SolidWorks Community. For the past two months or so, I have been working on a design project that calls for the creation of a 3-DOF Stewart Platform, which is motorized by three worm gear assemblies coupled with three lead screws which are attached to three rod end bearings. The rod end bearings allow the pivot of a top plate in all directions. The top plate is concentric to a center pylon and therefore making individual adjustments on one motor will also move the other two (for example, if one motor assembly tilts the plate down, the other two tilt the plate up to allow for the motion, as well as allowing for free tilt along the left and right sides of the rod end bearings).


Things are not going as smoothly however. When I mate one rod end bearing concentrically to one pin on the top plate, it defaults to a tilted position, along with mating another one which does the same thing and stays locked in place. When I try to mate the third one, I get an error that the pin is either locked at a distance from the rod end at an angle or at a linear distance. This is not to mention that the top plate bore hole won't mate concentrically to the pylon when a second rod end bearing is mated to a top plate pin, which also only seems to work sometimes when only one rod end bearing is mated to a top plate pin. I have looked through everything in the assembly to see if there are mates or drawings that were not drawn equally in space about 50 times now, and there doesn't appear to be any issue on those fronts. The rod end bearings were imported, although I did insert my own internal bearing into the part to get a realistic rod end bearing assembly working. Below is attached an image of the issue, as well as a Google drive folder with the assembly so you guys can take a look:


Final Design Concept - Google Drive


Error State.png


Can anyone provide any insight into this issue?


Thank you.