MECHANISM: slider acts like rigid body when upper limit is reached

[Bigfefi]

Hello everybody!
I'm using Creo 7 to simulate a mechanism that uses a piston (slider constraint with lower and upper limit, the green part) to partially rotate a cranck mechanism . The problem is that the rotating part wants to pull the piston beyond its limits and then simulation crashes. Actually when the piston is fully extended it acts as a rigid body, What I'd like to do is:
- Extend the piston
- Start rotating the levers
- Stop rotating
- Retract the piston
Any suggestion? I thought to replace the piston with a single part (a rod) but as simulation is not "correct"

 Any suggestion?

Best regards
Stefano

[tbraxton]

It is most likely an issue with constraints on a joint(s) not being valid kinematically. Look at each joint definition and make sure that you are controlling the DOFs in a valid manner.

To Calculate Degrees of Freedom and Redundancies

Tutorial:

Creo Parametric - Degrees of Freedom (DOF) and Redundancy Measures for Mechanisms

[Srinivasan-Iyer]

Your mechanism is not a 4 bar. It is a 5 bar mechanism. Hence, the linkage configuration is not determined. 

Have a look at the picture for the number of linkages. Link 1 is Fixed (Ground) member.