| # Standalone MuJoCo Simulator for Unitree G1 | |
| This is a standalone MuJoCo physics simulator for the Unitree G1 robot, extracted from the GR00T-WholeBodyControl repository. | |
| ## Features | |
| - **Physics Simulation**: Runs G1 robot in MuJoCo at 500Hz (2ms timestep) | |
| - **DDS Communication**: Uses Unitree SDK2 DDS for robot communication | |
| - **Compatible**: Works with existing `unitree_g1.py` control code via DDS | |
| - **Visualization**: Real-time 3D visualization of robot motion | |
| ## Directory Structure | |
| ``` | |
| mujoco_sim_g1/ | |
| ├── requirements.txt # Python dependencies | |
| ├── run_sim.py # Main launcher script | |
| ├── config.yaml # Simulation configuration | |
| ├── sim/ # Simulation modules | |
| │ ├── base_sim.py | |
| │ ├── simulator_factory.py | |
| │ ├── unitree_sdk2py_bridge.py | |
| │ └── ... | |
| └── assets/ # Robot models | |
| ├── g1_29dof_with_hand.xml | |
| └── meshes/*.STL | |
| ``` | |
| ## Installation | |
| ### 1. Create Virtual Environment (Recommended) | |
| ```bash | |
| cd mujoco_sim_g1 | |
| python3 -m venv venv | |
| source venv/bin/activate # On Windows: venv\Scripts\activate | |
| ``` | |
| ### 2. Install Dependencies | |
| ```bash | |
| pip install -r requirements.txt | |
| ``` | |
| **Note**: If you encounter issues with `rclpy`, you can comment out the ROS2 imports in `sim/base_sim.py` (lines 11, 609-617) if you don't need camera publishing. | |
| ## Usage | |
| ### Basic Usage | |
| ```bash | |
| # Activate environment | |
| source venv/bin/activate | |
| # Run the simulator | |
| python run_sim.py | |
| ``` | |
| The simulator will: | |
| 1. Load the G1 robot model | |
| 2. Initialize DDS communication on domain 0 | |
| 3. Open a MuJoCo visualization window | |
| 4. Start listening for motor commands via DDS | |
| ### Running with Your Robot Control Code | |
| Once the simulator is running, you can control it from another terminal: | |
| ```bash | |
| # In another terminal | |
| cd /home/yope/Documents/lerobot | |
| conda activate unitree_lerobot | |
| # Run your existing control code | |
| python test_locomotion_minimal.py | |
| ``` | |
| Your `unitree_g1.py` code will automatically connect to the simulator via DDS! | |
| ## Configuration | |
| Edit `config.yaml` to customize: | |
| - **SIMULATE_DT**: Simulation timestep (default: 0.002s = 500Hz) | |
| - **DOMAIN_ID**: DDS domain ID (default: 0) | |
| - **ENABLE_ONSCREEN**: Show visualization (default: true) | |
| - **USE_JOYSTICK**: Enable gamepad control (default: false) | |
| - **ROBOT_SCENE**: Path to MuJoCo XML scene | |
| ### PD Gains | |
| The simulator uses the following PD gains (matching NVIDIA GR00T): | |
| **Legs (indices 0-11):** | |
| - Hip joints: KP=150, KD=2 | |
| - Knee joints: KP=300, KD=4 | |
| - Ankle joints: KP=40, KD=2 | |
| **Waist (indices 12-14):** | |
| - All waist joints: KP=250, KD=5 | |
| **Arms (indices 15-28):** | |
| - Shoulders: KP=100, KD=2-5 | |
| - Elbows/Wrists: KP=20-40, KD=1-2 | |
| ## Troubleshooting | |
| ### ImportError: cannot import name 'ChannelFactoryInitialize' | |
| ```bash | |
| pip install --upgrade unitree-sdk2py | |
| ``` | |
| ### ROS2/rclpy errors | |
| If you don't need camera publishing, edit `sim/base_sim.py`: | |
| - Comment out line 11: `import rclpy` | |
| - Comment out lines 609-617 (ROS2 initialization) | |
| ### Meshes not found | |
| Make sure mesh paths in `assets/g1_29dof_with_hand.xml` are relative: | |
| ```xml | |
| <mesh file="meshes/pelvis.STL"/> <!-- Not absolute path --> | |
| ``` | |
| ### Robot falls immediately | |
| Check that: | |
| 1. PD gains match NVIDIA's values (see config.yaml) | |
| 2. Velocity command scaling is correct (ang_vel_scale=0.25, cmd_scale=[2.0, 2.0, 0.25]) | |
| 3. Observations for missing joints are zeroed out (indices 12, 14, 20, 21, 27, 28) | |
| ## Technical Details | |
| ### Communication | |
| The simulator publishes: | |
| - **`rt/lowstate`**: Robot state (joint positions, velocities, IMU, etc.) | |
| - **`rt/wirelesscontroller`**: Wireless remote controller state (if joystick enabled) | |
| The simulator subscribes to: | |
| - **`rt/lowcmd`**: Motor commands (position, velocity, torque, KP, KD) | |
| ### Coordinate Frames | |
| - **World frame**: Z-up | |
| - **Joint ordering**: 29 DOF (12 legs + 3 waist + 14 arms) | |
| - **IMU**: Quaternion in [w, x, y, z] format | |
| ### Performance | |
| - Simulation runs at ~500Hz (2ms timestep) | |
| - Viewer updates at ~50Hz (20ms) | |
| - Typical CPU usage: 20-40% on single core | |
| ## Files from GR00T-WholeBodyControl | |
| This standalone simulator was extracted from: | |
| - `gr00t_wbc/control/envs/g1/sim/` (simulation modules) | |
| - `gr00t_wbc/control/robot_model/model_data/g1/` (robot model files) | |
| - `gr00t_wbc/control/main/teleop/configs/g1_29dof_gear_wbc.yaml` (configuration) | |
| ## License | |
| Follows the license of the original GR00T-WholeBodyControl repository. | |