Simulate motion of a bearing block on a closed loop track 1

[AaronH]

All,

I want to simulate part of a machine I am developing. The basis of it is a bearing block that is mounted to a track that has a series of straight and curved sections that form a closed loop. Can someone recommend the proper joints, constraints, and driver(s) necessary to demonstrate a complete lap around the track? We have a few tutorials available that I have done that provided me a basic understanding of Motion, but none of them demonstrate this type of motion. I created a curve to represent the center of the track and used "point on curve" to constrain the two articulation points of the bearing plate. I then used a planar joint to keep the bearing from rolling about the path. I have had some success getting the bearing to move about the track path, but haven't been able to get it to make a full lap. I keep getting errors when I solve the solution. One question I have: what is the best method to get the bearing to move around the track at a constant velocity? Most methods I see are vector oriented. I think that is a problem because when it goes through the curve the vector direction needs to change (i.e. how to I apply a force normal to the bearing itself at all times).

Please see attached picture as an example of what I am working with.

Regards,
Aaron

 

[JohnRBaker]

First thing that you need to do is replace the "series of straight and curved sections" with a single curve, which can best be done using the...

Insert -> Curve from Curves -> Join...

...function.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[AaronH]

When I added the "point on curve" constraint I believe it did that for me. When I double click those constraints it shows only one curve selected and then click on "select curve" it highlights one continuous curve.

 

[AaronH]

I am finally making some progress. Up until now, my results have been very erratic. Simply adjusting the solution time would generate vastly different results. Sometimes the bearing would only travel part way though the path and stop with an error. I could vary settings, but it seemed to stop at the same point along a straight section of the path. Then other times it would seem to randomly jump around the path, meaning that if I indexed it through each animation step it would move very large amount each step.

Long story short I switched to the ADAMS solver and it works. However, my full path filename had spaces so I had to do a save as. Then I had to create a new simulation because it doesn't seem to carry that data over in a save as. :-/