robots/franka/mjcf/README.md

Files in this folder are modified from mujoco_menagerie. The modifications are renaming the joint names to be consistent with the URDF file in urdf folder and the USD file in usd folder.

Below is the original README from the mujoco_menagerie repo:

Franka Emika Panda Description (MJCF)

Requires MuJoCo 2.3.3 or later.

Overview

This package contains a simplified robot description (MJCF) of the Franka Emika Panda developed by Franka Emika. It is derived from the publicly available URDF description.

URDF → MJCF derivation steps

1. Converted the DAE mesh files to OBJ format using Blender.
2. Processed .obj files with obj2mjcf.
3. Eliminated the perfectly flat link0_6 from the resulting submeshes created for link0.
4. Created a convex decomposition of the STL collision mesh file for link5 using V-HACD.
5. Added <mujoco> <compiler discardvisual="false"/> </mujoco> to the URDF's <robot> clause in order to preserve visual geometries.
6. Loaded the URDF into MuJoCo and saved a corresponding MJCF.
7. Matched inertial parameters with inertial.yaml.
8. Added a tracking light to the base.
9. Manually edited the MJCF to extract common properties into the <default> section.
10. Added <exclude> clauses to prevent collisions between link7 and link8.
11. Manually designed collision geoms for the fingertips.
12. Added position-controlled actuators for the arm.
13. Added an equality constraint so that the left finger mimics the position of the right finger.
14. Added a tendon to split the force equally between both fingers and a position actuator acting on this tendon.
15. Added scene.xml which includes the robot, with a textured groundplane, skybox, and haze.

MJX

A version of the Franka Emika Panda environment was created for MJX. Steps:

1. Added mjx_panda.xml, forked from panda.xml.
2. Added mjx_scene.xml and mjx_single_cube.xml, forked from scene.xml.
3. Gripper collision geometries were modified to contain less geoms. A capsule collision geom was added to the hand.
4. Solver parameters were tuned for performance.
5. Actuator kp and kv were reduced for more stable simulation.
6. Added a site to the gripper.
7. Removed tendon and added position actuator for the gripper. Changed gripper ctrlrange.

License

This model is released under an Apache-2.0 License.