Add MJX variant of g1.xml.

CHANGELOG.md

@@ -2,12 +2,18 @@
 
 All notable changes to this repository will be documented here.
 
+## [30/05/2025]
+
+- Added an MJX-tuned version of the G1 model.
+
 ## [19/05/2025]
 
 - Added [YAM manipulator](i2rt_yam/README.md) from I2RT Robotics.
 
 ## [22/04/2025]
+
 - Adds changelog structure, contributor list, and PR template.
 
 ## [07/09/2022]
+
 - Initial release.

README.md

@@ -249,7 +249,7 @@ Menagerie, see [CONTRIBUTING](CONTRIBUTING.md).
 | Fourier N1 | Fourier Robotics | 30 | [Apache-2.0](fourier_n1/LICENSE) |✖️|
 | Robotis OP3 | Robotis | 20 | [Apache-2.0](robotis_op3/LICENSE) |✖️|
 | TALOS | PAL Robotics | 32 | [Apache-2.0](pal_talos/LICENSE) |✖️|
-| Unitree G1 | Unitree Robotics | 37 | [BSD-3-Clause](unitree_g1/LICENSE) |✖️|
+| Unitree G1 | Unitree Robotics | 37 | [BSD-3-Clause](unitree_g1/LICENSE) |✔️|
 | Unitree H1 | Unitree Robotics | 19 | [BSD-3-Clause](unitree_h1/LICENSE) |✖️|
 
 **Quadrupeds.**

unitree_g1/CHANGELOG.md

@@ -2,10 +2,20 @@
 
 All notable changes to this model will be documented in this file.
 
+## [30/05/25]
+
+- Add MJX variant of [g1.xml](g1.xml), with manually designed collision geoms and contact pairs.
+
+<p float="left">
+  <img src="g1_mjx_colliders.png" width="400">
+</p>
+
 ## [10/12/2024]
+
 - Use updated models from Unitree's official [repo](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g1_description) (sha: c20ca8f1fe5e519474c6c8d10b1ce5c719dd7a65).
   - Model without hands: [g1_29dof_rev_1_0](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g1_description/g1_29dof_rev_1_0.xml)
   - Model with hands: [g1_29dof_with_hand_rev_1_0](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g1_description/g1_29dof_with_hand_rev_1_0.xml)
 
 ## [20/05/2024]
+
 - Initial release.

unitree_g1/README.md

@@ -13,7 +13,7 @@ This package contains a simplified robot description (MJCF) of the [G1 Humanoid
 Robot](https://www.unitree.com/g1/) developed by [Unitree
 Robotics](https://www.unitree.com/). It is derived from the [publicly available
 MJCF
-description](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g1_description/g1_29dof_rev_1_0.xml). Specifically, this model has the fully actuated waist but not the full hands.
+description](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g1_description/g1_29dof_rev_1_0.xml).
 
 <p float="left">
   <img src="g1.png" width="400">
@@ -28,6 +28,37 @@ description](https://github.com/unitreerobotics/unitree_ros/blob/master/robots/g
 4. Added joint position actuators (needs tuning).
 5. Applied similar edits to `g1_with_hands.xml`.
 
+## MJX
+
+A version of [g1.xml](g1.xml) for use in [MJX](https://mujoco.readthedocs.io/en/stable/mjx.html) is available in `scene_mjx.xml` with the following changes:
+
+* Manually designed collision geoms and corresponding contact pairs (see figure below).
+* Tuned solver and line search iterations.
+* Used lower, more realistic PD gains.
+* Added `home` and `knees_bent` keyframes.
+
+The above model was successfully transfered to hardware in [MuJoCo Playground](https://playground.mujoco.org/).
+
+<p float="left">
+  <img src="g1_mjx_colliders.png" width="400">
+</p>
+
 ## License
 
 This model is released under a [BSD-3-Clause License](LICENSE).
+
+## Publications
+
+If you use the MJX model in your work, please use the following citation:
+
+```bibtex
+@misc{zakka2025mujocoplayground,
+  title={MuJoCo Playground},
+  author={Kevin Zakka and Baruch Tabanpour and Qiayuan Liao and Mustafa Haiderbhai and Samuel Holt and Jing Yuan Luo and Arthur Allshire and Erik Frey and Koushil Sreenath and Lueder A. Kahrs and Carmelo Sferrazza and Yuval Tassa and Pieter Abbeel},
+  year={2025},
+  eprint={2502.08844},
+  archivePrefix={arXiv},
+  primaryClass={cs.RO},
+  url={https://arxiv.org/abs/2502.08844},
+}
+```