What is position violation ?

Hello every one. I wish you all the best.

I've faced problem while using simscape multibody. Can any one help me, please?

I've built a simple mechanical rack and pinon mechanism using SOLIDWORKS and imported the model to MATLAB to design a control system. I made use of rack and pinon block as a constrain between the rack block and the pinon block. when I run the model it always appears an error message says " the model not assembled: position violation" but when I remove the rack and pinon block the model run well and no error message appears.

Does anybody know how to solve this problem?

A photo of the model is attached and a simulink file of the model is attached as well.

Answer 1

[Steve Miller]

Hi Hamzah,

The error message about not being able to assemble usually means that your model is kinematically impossible. One or more degrees of freedom are constrained in multiple, inconsistent ways. Usually, you have a frame that is not properly oriented or properly positioned.

You have done a good job identifying a block that likely close to the frame that is in the wrong position or orientation. If you look at the diagrams in the documentation for the Rack and Pinion Constraint block, you will see how the frames need to be oriented and positioned. Compare these to the two frames connected to your Rack and Pinion Constraint block, and you will see the change you need to make. I would have attempted it on the model you attached, but the parameter file is missing.

Thanks,

--Steve

[cindy lemoine]

Steve i have a similar problem using the bevel gear constraint, is there a way for me to upload my model so you can take a look at it?

[MathWorks Simscape Team]

Hi Cindy - create a new MATLAB Answers post and attach the model. Also, if you modify your MATLAB Answers profile and let people send you emails, I can respond directly to you.