unitree-g1/reference/sources/github-unitree-mujoco.md

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:

sudo apt install libyaml-cpp-dev libspdlog-dev libboost-all-dev libglfw3-dev

Install unitree_sdk2 to /opt/unitree_robotics:

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:

cd simulate/
ln -s ~/.mujoco/mujoco-3.3.6 mujoco

Compile:

mkdir build && cd build && cmake .. && make -j4

Test:

./unitree_mujoco -r go2 -s scene_terrain.xml

Python Simulator Setup

Dependencies:

pip3 install mujoco pygame
pip3 install -e unitree_sdk2_python

Run:

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