Articulation Roots causing weird joint positions and velocities

Isaac Sim Version
5.0.0

Operating System

Ubuntu 24.04

GPU Information

  • Model: RTX 5080
  • Driver Version: 580.65.06

Topic Description

I am trying to add Articulation Roots to my robot to allow ROS2 control. When I add an Articulation Root, it causes the arms of my robot to go to weird joint positions and glitch there. I am unsure on the cause of this glitching and want to be able to control my arms.

Steps to Reproduce

Reproducing the error is fairly difficult because it involves attaching the OpenArm onto an existing robot and setting an Articulation Root. The way it is done is by using the macro OpenArm provides for their v10 and expanding the xacro in the robot description and adding a fixed joint to the base_link of the arm. Then the arm itself is flattened so that it can be set up with Articulation Roots for ROS2 control via the Isaac Action Graph. I haven’t even set up any of the action graph parts, it glitches out in just setting up articulation roots.

Video shows the arm glitching when Articulation Roots are enabled, not glitching when disabled.

Error Messages

No errors. Unless I try a hierarchical structure with base_link as the only Articulation Root, then I get issues with my joints not being valid and an Xform Reset issue (I don’t understand either)

Additional Information

What I’ve Tried

I’ve tried a hierarchical structure instead of multiple Articulation Roots and I get issues with my joints and this reset XForm Transform Stack which I don’t totally understand.

Related Issues

This could be an issue with the collision meshes of my arm but I am unsure and don’t know how I would test that out. Also the OpenArm is online and been used in other projects so it should work fine.

For a single robot, you should typically have only one Articulation Root at the base of the entire robot hierarchy. Multiple roots can cause unexpected behavior with joints and transforms.

Could you clarify what exact issues are happening?