# Unitree MuJoCo
**Source:** https://github.com/unitreerobotics/unitree_mujoco
**Fetched:** 2026-02-13
**Type:** GitHub Repository README

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# Unitree MuJoCo Simulator - Complete Overview

## Project Description

"unitree_mujoco is a simulator developed based on Unitree sdk2 and mujoco." It enables seamless integration of control programs from unitree_sdk2, unitree_ros2, and unitree_sdk2_python into simulation, facilitating "a seamless transition from simulation to physical development." The project provides both C++ and Python implementations.

## Supported Robots

The simulator supports multiple Unitree quadruped and humanoid robots:
- Go2, B2, B2w, H1 (using unitree_go IDL)
- G1, H1-2 (using unitree_hg IDL)

## Key Supported Messages

The system currently supports low-level control and state feedback:
- **LowCmd**: Motor control commands
- **LowState**: Motor state information
- **SportModeState**: Robot position and velocity data
- **IMUState**: Torso IMU measurements (G1 only)

## Directory Structure

```
- simulate/          : C++ simulator (recommended)
- simulate_python/   : Python simulator
- unitree_robots/    : MJCF robot descriptions
- terrain_tool/      : Terrain generation utilities
- example/           : Sample implementations
```

## C++ Simulator Installation

**Dependencies:**
```bash
sudo apt install libyaml-cpp-dev libspdlog-dev libboost-all-dev libglfw3-dev
```

**Install unitree_sdk2** to `/opt/unitree_robotics`:
```bash
git clone https://github.com/unitreerobotics/unitree_sdk2.git
cd unitree_sdk2/ && mkdir build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=/opt/unitree_robotics
sudo make install
```

**Install MuJoCo** and create symlink:
```bash
cd simulate/
ln -s ~/.mujoco/mujoco-3.3.6 mujoco
```

**Compile:**
```bash
mkdir build && cd build && cmake .. && make -j4
```

**Test:**
```bash
./unitree_mujoco -r go2 -s scene_terrain.xml
```

## Python Simulator Setup

**Dependencies:**
```bash
pip3 install mujoco pygame
pip3 install -e unitree_sdk2_python
```

**Run:**
```bash
cd simulate_python && python3 unitree_mujoco.py
```

## Configuration

**C++ Config** (`simulate/config.yaml`):
- Robot selection, scene file, DDS domain ID
- Joystick settings (Xbox/Switch support)
- Network interface (default: "lo" for simulation)
- Elastic band support for humanoid initialization

**Python Config** (`simulate_python/config.py`):
- Same parameters as C++ version
- Configurable simulation timestep (SIMULATE_DT)
- Viewer refresh rate (VIEWER_DT)

## Terrain Generation

The "terrain_tool folder contains utilities for parametrically creating simulation environments, including stairs, rough ground, and heightmaps."

## Sim-to-Real Transition

Three integration examples demonstrate controller transfer:

1. **unitree_sdk2 (C++)**:
   - Compile in `example/cpp/build`
   - Run: `./stand_go2` (simulation) or `./stand_go2 enp3s0` (real robot)
   - Domain ID switches from 1 to 0 between environments

2. **unitree_sdk2_python**:
   - Run: `python3 stand_go2.py` (simulation) or with network interface for hardware

3. **unitree_ros2**:
   - Requires unitree_ros2 environment setup
   - Domain ID configuration via `ROS_DOMAIN_ID` environment variable

## Joystick Support

Gamepad controllers (Xbox/Switch layouts) simulate the Unitree wireless controller, publishing to the "rt/wireless_controller" topic. Custom button mappings can be configured in source files using jstest tool output.

## Humanoid-Specific Features

"elastic band was designed to simulate the lifting and lowering of humanoid robots," enabling safe initialization. Press 9 to toggle, 7 to lower, 8 to lift.

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**License:** BSD-3-Clause | **Repository:** github.com/unitreerobotics/unitree_mujoco