Humanoid Demo: Experiments with Unitree G1

Posted on 2025-06-09 :: Tags: RL, DRL, IL, GAIL, AIRL, Bipedal, Biped, Humanoid, Unitree/G1, IsaacGym

Introduction

In this blog, we will conduct some experiments on Unitree G1. Specifically, using RL + IL and Motion Retargeting from the CMU MoCap dataset, we will attempt to teach Unitree G1 to run, jump, ...

Unitree G1 Spec

The Unitree G1 has 2 versions(i.e., G1-basic and G1-edu), and its corresponding specifications are as follows:

	G1	G1-EDU
Key Dimensions	1320x450x200 mm	1320x450x200 mm
Calf + Thigh Length	0.6m	0.6m
Arm Span	About 0.45M	About 0.45M
Total Degrees of Freedom (Joint Freedom）	23	23~43
Single Leg Degrees of Freedom	6	6
Waist Degrees of Freedom	1	1 + (Optional 2 additional waist degrees of freedom)
Single Arm Degrees of Freedom	5	5
Single Hand Degrees of Freedom	/	7(Optional Force outrolled three-fingered dexterous hand Dex3-1) + 2(Optional 2 additional wrist degrees of freedom)
Joint motor	Low inertia high-speed internal rotor PMSM (permanent magnet synchronous motor, better response speed and heat dissipation)	Low inertia high-speed internal rotor PMSM (permanent magnet synchronous motor, better response speed and heat dissipation)
Maximum Torque of Knee Joint	90N.m	120N.m
Joint Angle Limits	Waist joint：Z±155° Knee joint：0~165° Hip joint：P±154°、R-30~+170°、Y±158°	Waist joint：Z±155°、X±45°、Y±30° Knee joint：0~165° Hip joint：P±154°、R-30~+170°、Y±158° Wrist joint：P±92.5°、Y±92.5°
Sensor Configuration	Depth Camera(Intel RealSense D435i) + 3D LiDAR(LIVOX-MID360)	Depth Camera(Intel RealSense D435i) + 3D LiDAR(LIVOX-MID360)
Total Weight	About 35kg	About 35kg+

Joints

Unitree G1 has 23(basic)/29(edu) total degrees of freedom(DOFs), where each arm possesses 5(basic)/7(edu) degrees of freedom, each leg has 6, and the waist features 1(basic)/3(edu) degree of freedom.

Joint Numbering and Joint Limits

G1(basic) G1(edu)

Joint Name	Limits	Joint Number
{left,right}_hip_pitch_joint `{L,R}_LEG_HIP_PITCH`	-2.5307~2.8798 rad	left: 0 right: 6
left_hip_roll_joint `L_LEG_HIP_ROLL`	-0.5236~2.9671 rad	1
right_hip_roll_joint `R_LEG_HIP_ROLL`	-2.9671~0.5236 rad	7
{left,right}_hip_yaw_joint `{L,R}_LEG_HIP_YAW`	-2.7576~2.7576 rad	left: 2 right: 8
{left,right}_knee_joint `{L,R}_LEG_KNEE`	-0.087267~2.8798 rad	left: 3 right: 9
{left,right}_ankle_pitch_joint `{L,R}_LEG_ANKLE_PITCH`	-0.87267~0.5236 rad	left: 4 right: 10
{left,right}_ankle_roll_joint `{L,R}_LEG_ANKLE_ROLL`	-0.2618~0.2618 rad	left: 5 right: 11
waist_yaw_joint `WAIST_YAW`	-2.618~2.618 rad	12
{left,right}_shoulder_pitch_joint `{L,R}_SHOULDER_PITCH`	-3.0892~2.6704 rad	left:13 right: 18
left_shoulder_roll_joint `L_SHOULDER_ROLL`	-1.5882~2.2515 rad	14
right_shoulder_roll_joint `R_SHOULDER_ROLL`	-2.2515~1.5882 rad	19
{left,right}_shoulder_yaw_joint `{L,R}_SHOULDER_YAW`	-2.618~2.618 rad	left:15 right: 20
{left,right}_elbow_joint `{L,R}_ELBOW`	-1.0472~2.0944 rad	left: 16 right: 21
{left,right}_wrist_roll_joint `{L,R}_WRIST_ROLL`	-1.972222054~1.972222054 rad	left: 17 right: 22

Joint Name	Limits	Joint Number
{left,right}_hip_pitch_joint `{L,R}_LEG_HIP_PITCH`	-2.5307~2.8798 rad	left: 0 right: 6
left_hip_roll_joint `L_LEG_HIP_ROLL`	-0.5236~2.9671 rad	1
right_hip_roll_joint `R_LEG_HIP_ROLL`	-2.9671~0.5236 rad	7
{left,right}_hip_yaw_joint `{L,R}_LEG_HIP_YAW`	-2.7576~2.7576 rad	left: 2 right: 8
{left,right}_knee_joint `{L,R}_LEG_KNEE`	-0.087267~2.8798 rad	left: 3 right: 9
{left,right}_ankle_pitch_joint `{L,R}_LEG_ANKLE_PITCH`	-0.87267~0.5236 rad	left: 4 right: 10
{left,right}_ankle_roll_joint `{L,R}_LEG_ANKLE_ROLL`	-0.2618~0.2618 rad	left: 5 right: 11
waist_yaw_joint `WAIST_YAW`	-2.618~2.618 rad	12
waist_roll_joint `WAIST_ROLL`	-0.52~0.52 rad	13
waist_pitch_joint `WAIST_PITCH`	-0.52~0.52 rad	14
{left,right}_shoulder_pitch_joint `{L,R}_SHOULDER_PITCH`	-3.0892~2.6704 rad	left:15 right: 22
left_shoulder_roll_joint `L_SHOULDER_ROLL`	-1.5882~2.2515 rad	16
right_shoulder_roll_joint `R_SHOULDER_ROLL`	-2.2515~1.5882 rad	23
{left,right}_shoulder_yaw_joint `{L,R}_SHOULDER_YAW`	-2.618~2.618 rad	left:17 right: 24
{left,right}_elbow_joint `{L,R}_ELBOW`	-1.0472~2.0944 rad	left: 18 right: 25
{left,right}_wrist_roll_joint `{L,R}_WRIST_ROLL`	-1.972222054~1.972222054 rad	left: 19 right: 26
{left,right}_wrist_pitch_joint `{L,R}_WRIST_PITCH`	-1.614429558~1.614429558 rad	left: 20 right: 27
{left,right}_wrist_yaw_joint `{L,R}_WRIST_YAW`	-1.614429558~1.614429558 rad	left: 21 right: 28

Reference Motion Retargeting

The skeleton model (henceforth referred to as 'CMU-MoCap') used in the CMU MoCap dataset and the robot model of Unitree G1 have different proportions and skeletal structures. Therefore, to reuse the MoCap animation dataset for Unitree G1, the technique called retargeting is needed. Retargeting is the process of adapting the animation from the source to the target character. Furthermore, humanoid retargeting is the process of transferring animation data from one humanoid character (the source) to another (the target).

Motion retargeting requires a consistent starting point for transferring animation accurately, and the T-pose serves this purpose. T-pose is a neutral, standardized pose (arms outstretched, resembling the letter 'T') used as a reference point(pose) for retargeting animations between different character skeletons. The following shows the T-pose for CMU-MoCap and Unitree-G1 respectively,