Unitree G1 Description (URDF & MJCF)

Overview

This package includes a universal humanoid robot description (URDF & MJCF) for the Unitree G1, developed by Unitree Robotics.

The package provides two model variants:

• urdf/g1_23dof.urdf - G1 with 23 degrees of freedom (fixed waist)
• urdf/g1_29dof.urdf - G1 with 29 degrees of freedom (adding waist and wrist mobility)

Both models support simulation environments including MuJoCo and Gazebo.

Robot Structure

G1 humanoid has either 23 or 29 joints depending on the variant. The base 23-DOF configuration includes:

root [⚓] => /pelvis/
    left_hip_pitch_joint [⚙+Y] => /left_hip_pitch_link/
        left_hip_roll_joint [⚙+X] => /left_hip_roll_link/
            left_hip_yaw_joint [⚙+Z] => /left_hip_yaw_link/
                left_knee_joint [⚙+Y] => /left_knee_link/
                    left_ankle_pitch_joint [⚙+Y] => /left_ankle_pitch_link/
                        left_ankle_roll_joint [⚙+X] => /left_ankle_roll_link/
    right_hip_pitch_joint [⚙+Y] => /right_hip_pitch_link/
        right_hip_roll_joint [⚙+X] => /right_hip_roll_link/
            right_hip_yaw_joint [⚙+Z] => /right_hip_yaw_link/
                right_knee_joint [⚙+Y] => /right_knee_link/
                    right_ankle_pitch_joint [⚙+Y] => /right_ankle_pitch_link/
                        right_ankle_roll_joint [⚙+X] => /right_ankle_roll_link/
    waist_yaw_joint [⚙+Z] => /torso_link/
        left_shoulder_pitch_joint [⚙+Y] => /left_shoulder_pitch_link/
            left_shoulder_roll_joint [⚙+X] => /left_shoulder_roll_link/
                left_shoulder_yaw_joint [⚙+Z] => /left_shoulder_yaw_link/
                    left_elbow_joint [⚙+Y] => /left_elbow_link/
                        left_wrist_roll_joint [⚙+X] => /left_wrist_roll_link/
        right_shoulder_pitch_joint [⚙+Y] => /right_shoulder_pitch_link/
            right_shoulder_roll_joint [⚙+X] => /right_shoulder_roll_link/
                right_shoulder_yaw_joint [⚙+Z] => /right_shoulder_yaw_link/
                    right_elbow_joint [⚙+Y] => /right_elbow_link/
                        right_wrist_roll_joint [⚙+X] => /right_wrist_roll_link/

29-DOF variant additions:

• waist_roll_joint and waist_pitch_joint
• Left wrist: left_wrist_pitch_joint, left_wrist_yaw_joint
• Right wrist: right_wrist_pitch_joint, right_wrist_yaw_joint

Usages

MuJoCo (recommend)

pip install mujoco

# Select specific model
python -m mujoco.viewer --mjcf=mjcf/scene_29dof.xml
python -m mujoco.viewer --mjcf=mjcf/scene_23dof.xml

RViz

# Default (23-DOF)
ros2 launch g1_description display.launch

# Select specific model
ros2 launch g1_description display.launch model:=23dof
ros2 launch g1_description display.launch model:=29dof

Gazebo

# Default (23-DOF)
ros2 launch g1_description gazebo.launch

# Select specific model
ros2 launch g1_description gazebo.launch model:=23dof
ros2 launch g1_description gazebo.launch model:=29dof