37 lines
1.5 KiB
Markdown
37 lines
1.5 KiB
Markdown
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# Unitree A1 Description (MJCF)
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Requires MuJoCo 2.2.2 or later.
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## Overview
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This package contains a simplified robot description (MJCF) of the [A1 Quadruped
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Robot](https://www.unitree.com/a1/) developed by [Unitree
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Robotics](https://www.unitree.com/). It is derived from the [publicly available
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URDF
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description](https://github.com/unitreerobotics/unitree_mujoco/tree/main/data/a1/urdf).
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<p float="left">
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<img src="a1.png" width="400">
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</p>
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## URDF → MJCF derivation steps
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1. Converted the DAE [mesh
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files](https://github.com/unitreerobotics/unitree_mujoco/tree/main/data/a1/meshes)
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to OBJ format using [Blender](https://www.blender.org/).
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2. Processed `.obj` files with [`obj2mjcf`](https://github.com/kevinzakka/obj2mjcf).
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3. Added `<mujoco> <compiler discardvisual="false"/> </mujoco>` to the URDF's
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`<robot>` clause in order to preserve visual geometries.
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4. Loaded the URDF into MuJoCo and saved a corresponding MJCF.
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5. Added a `<freejoint/>` to the base, and a tracking light.
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6. Manually edited the MJCF to extract common properties into the `<default>` section.
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7. Manually designed collision geometries.
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8. Shifted joint reference values and ranges so that 0 corresponds to standing pose.
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9. Softened the contacts of the feet to approximate the effect of rubber and
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increased `impratio` to reduce slippage.
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10. Added `scene.xml` which includes the robot, with a textured groundplane, skybox, and haze.
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## License
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This model is released under a [BSD-3-Clause License](LICENSE).
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