robot_model_analyzer

robot_model_analyzer is a ROS 2 C++ package that performs analysis on a robot's URDF model using Pinocchio. It retrieves the robot description from the parameter server or a topic, parses the URDF, and runs key computations including:

• Forward kinematics to the end-effector
• Jacobian calculation
• Collision detection

Features

• ✅ Subscribes to /robot_description topic (e.g., from robot_state_publisher)
• ✅ Optionally fetches URDF from the parameter server
• ✅ Saves URDF to disk
• ✅ Parses the URDF using Pinocchio
• ✅ Computes:
  • End-effector transform
  • Frame Jacobian
  • Collision detection between links

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Dependencies

• ROS 2 (tested with Humble)
• Pinocchio
• urdf_parser
• ament_index_cpp

Make sure Pinocchio is installed and visible to your C++ build system.

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Usage

1. Build the package

colcon build --packages-select robot_model_analyzer
source install/setup.bash

2. Run the node

Make sure your robot description is published by robot_state_publisher or another node. Then run:

ros2 run robot_model_analyzer robot_model_analyzer

3. Set the end-effector frame (optional)

You can specify the end-effector frame via a parameter:

ros2 run robot_model_analyzer robot_model_analyzer --ros-args -p ee_frame:=<your_ee_frame>

If not specified, it defaults to ee_link.

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Output

The node logs and prints:

• The transform of the end-effector
• The Jacobian matrix at the end-effector
• Any collisions detected between model links

Example console output:

End-effector transform:
...
Jacobian at end-effector:
...
Collision detected between link1 and link2

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How It Works

1. Subscribes to /robot_description topic (or gets parameter)
2. Parses the URDF using urdf_parser
3. Saves URDF as temp.urdf in a local directory
4. Loads the model using Pinocchio
5. Computes:
   • Forward kinematics to the specified frame
   • Frame Jacobian
   • Collision checks between all pairs

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