Modeling a collision between two rotating bodies

Hello,

I have problem in modeling collision/Force impact reactions between two rotating bodies.

I have a readymade CAD-file imported to SimMechanics 2G, and I'm trying to simulate the contact between two bodies on rotating shafts.

The Gear is rotating and applying force to the counter-part via the teeth. Counterpart reacts downward and spring pushes it back to original position before next hit.

The problem is that I'm having problems to simulate the contact between these two. I've tried using translational/rotational hard-stops and even got some reaction when using only 1 tooth. However even then the Counter-part had impact reaction and another reaction when the tooth was 180 degrees from the Counter-part.

How can I connect these two parts in SimMechanics so that each tooth applies force to the Counter-part upon impact?

BR, Eetu

Answer 1

[Sebastian Castro]

It's not all that straightforward to make these complex contact forces, but it's doable. There is a basic contact forces library on the File Exchange which can help you get started with some ideas:

http://www.mathworks.com/matlabcentral/fileexchange/47417-simmechanics-contact-forces-library

In particular, the Geneva drive video/example seems most relevant to what you want to do.

http://www.mathworks.com/videos/modeling-contact-forces-in-a-geneva-drive-94292.html

- Sebastian

[Eetu Mäkiö]

Ok thanks, I saw the Geneva Drive earlier but didn't realize it would be suitable for this use. I'll dive into that one and see if I can make it work.

[Eetu Mäkiö]

Ok, I've worked on this for a while now and thougth I make a comment in case anybody else in wondering with the similiar problem.

So I used the Geneva Drive example as reference. From there you can get a "Circle to Finite Line" -collision block that seems to do the trick. Just point the transformation coordinates in the two colliding bodies as in the Geneva Drive example and do a little parameter adjusting inside the collision block and your're good to go. Each collision of course requires its own block.

There is also some quite helpful info in the "Circle to Finite Line" block mask which tells how use the block properly.