Unitree A1 Description (MJCF)

Requires MuJoCo 2.2.2 or later.

Overview

This package contains a simplified robot description (MJCF) of the A1 Quadruped Robot developed by Unitree Robotics. 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. Added <mujoco> <compiler discardvisual="false"/> </mujoco> to the URDF's <robot> clause in order to preserve visual geometries.
4. Loaded the URDF into MuJoCo and saved a corresponding MJCF.
5. Added a <freejoint/> to the base, and a tracking light.
6. Manually edited the MJCF to extract common properties into the <default> section.
7. Manually designed collision geometries.
8. Shifted joint reference values and ranges so that 0 corresponds to standing pose.
9. Softened the contacts of the feet to approximate the effect of rubber and increased impratio to reduce slippage.
10. Added scene.xml which includes the robot, with a textured groundplane, skybox, and haze.

License

This model is released under a BSD-3-Clause License.