Error in simscape multibody "...Prismatic' has base and follower ports that are rigidly connected; it is ignored. Resolve this issue in order to simulate the model"

Hello.

I imported a CAD model into simscape multibody and when i try to simulate it i get this error:

Prismatic Joint 'Tracking_structure1/Prismatic' has base and follower ports that are rigidly connected; it is ignored. Resolve this issue in order to simulate the model.

Does anyone know what this error is?

Thank you

Answer 1

[Vasco Lenzi]

It seems you have a prismatic joint placed between two frames that are already directly connected, either through a connection line or because they belong to the same body. You can easily reproduce this error in a smaller model to better understand why it happens:

As you can see the prismatic joint frames B&F are connected to something that is rigidly connected (in this case is the same frame!).

The frames of a joint needs to be part of two separated body parts (usually)

Did this happens with the resulting model imported using >>smimport ?

Or did the error appeared when you modifed the imported model?

This may be due to "bad" modeling in the CAD environment where joint may have been placed simply in order to build up something, but without thoughts for thedynamc behaviour of the systems. The best way to ensure repeatable import is to address the issue in the cad environment and test the model again after importing

[Eleni.T]

Thankyou! The problem was within the CAD modelling

[RONSON RAJAN]

I have the same issue and I used Smiimport function, is there any way to solve it??

[Vasco Lenzi]

Hi Ronson

This issue comes if the CAD model is not setup correctly. You need to improve modeling of the CAD system in your CAD software of choice before importing.

see for Autodesk how the constraint vs joints are mapped:

https://ch.mathworks.com/help/physmod/smlink/ref/-inventor-constraint-simmechanics-joint-correspondence.html

For SolidWorks:

https://ch.mathworks.com/help/physmod/smlink/ref/mates-and-joints.html

For PTC/Creo:

https://ch.mathworks.com/help/physmod/smlink/ref/-inventor-constraint-simmechanics-joint-correspondence-1.html

For Onshape:

https://ch.mathworks.com/help/physmod/sm/ug/onshape-import.html