Isaac Joint inspector does not recognize all degrees of freedom for custom robot

Hey. So I’m trying to drive a custom robot I’ve made in the Isaac simulator. I modeled the robot in onshape and used the onshape importer to bring it into Isaac.

The problem I’m having is that the articulation inspector isn’t recognizing that my robot has 3 degrees of freedom (it says it only sees one), and only allows me to drive one of the joints. All three of the joints on the robot are prismatic. The hierarchy for the robot can be seen in the image.

Screenshot from 2023-03-02 16-51-51

I used the slider joint in onshape to define the motion of each of the joints.
Any help is appreciated, thank you!

Hi @juan17

Can you please share the .usd for testing it?

Hi @juan17 , as requested earlier, can you please share the .usd?

Hey sorry, I gave up and just started using the urdf importer. I tried again with the onshape importer however and now the all axes are “recognized”. The problem now is a few aren’t driving the correct joints and all the limits I set in Onshape are screwed up in the simulator. I’ve attached the usd file below.

Sim_Jack_Stand.usd (3.3 KB)

Regarding the joint drives: remember that it doesn’t include the stiffness and damping when importing from onshape. That’s a post processing required to properly drive your robot.

Regarding the limits: due to a limitation on Onshape’s importing API, it doesn’t provide us current joint value of the assembly, therefore we need to assume something, and we decided to assume it’s at zero pose. So you need to ensure it is at zero pose before importing, otherwise the limits will be screwed up indeed.

It’s curious that the articulation inspector was not seeing the other joints. Maybe it was missing a joint drive at them?