Lula Kinematics Solver on Custom Made Robot FAIL, tested using Lula Widget

Omniverse Isaac Sim
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Issue Resolved :)

Common Mistakes to Avoid When Using Lula: (My Experience)

  1. It’s often best to download a URDF dataset for any robotic arm from an official website. Alternatively, look for Nvidia Isaac Sim URDFs in isaac.omni.motion_generation and inside the motion_configs folder, where you’ll find many URDF files.

  2. If your CAD model is prebuilt or you are modifying a robotic arm, it’s always better to convert the CAD model to URDF and then use the URDF importer in Isaac. A common mistake I made was exporting the robotic arm as an FBX file and then importing it using the basic import option. This resulted in the arm being imported in USD but through FBX format but not URDF, and I had to manually add joints, which created numerous issues. When working with kinematics solvers, ensure you have a robust, error-free URDF.

  3. The best resource I found for URDFs is [GitHub repository - URDF Datasets](GitHub - Daniella1/urdf_files_dataset).
    I downloaded a Kuka model from there and successfully implemented the Lula Kinematics Solver (worked 100%)

  4. Never forget to use the Loaded Scenario Template Extension as it is crucial for Lula and other designs using URDF.
    Without this template, it won’t work.

  5. If you have any fixed joints or other joints that are not part of an articulation, go to those joints and
    click Exclude from Articulation.

Long Story Short

  1. Follow the tutorial exactly* as described in the documentation: Motion Generation with Lula Kinematics

  2. Download the Lula Kinematics Template Zip file, paste it inside the exts/ folder, and your extension will be loaded.

  3. Simply replace the URDF, XRDF, and USD files of your robot (when you import a URDF model, a USD file will be generated in the same folder—take a look and use that usd_path in this code and run it. It will work—100% guaranteed.

  4. The biggest challenge when implementing Lula algorithms is the URDF file management 🫡 hence be carefull with URDF*

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