#Joint modules (172)

How to Build a Humanoid Robot: A Seven-Layer Constraint Chain from Joint Modules to Sim-to-Real

A humanoid robot is not an assembly of seven modules but a stack of physics equations that set each other's boundary conditions. This article computes the whole-machine stack layer by layer: joint motor modules (declared torque versus real quasi-static CoP demand — BHL's hip has only 0.9x margin) -> IMU (lever-arm pseudo-acceleration is 21,752x the sensor noise floor, so mounting position matters four orders of magnitude more than the datasheet) -> materials and structure (three BOM revisions of AgiBot's X1 as a load-path history: every part entering the closed-chain drivetrain upgraded to 7075-T6 / TC4 / 17-4PH) -> sensors (fix the observation space before the shopping list) -> battery and BMS ('all joints at peak simultaneously' is physically impossible: G1's 46,062 W against a 421 Wh pack is 109 C) -> software control and the CAN-level low-side boards (22 nodes at 500 Hz on one bus is 130.9% load, so it must be split into four) -> simulation training and sim-to-real (9 of 12 real failure modes are hardware calibration, not simulation fidelity). Every figure comes from programmatic parsing of the five machines' public model files plus official vendor specifications, and is recomputable.

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HumanoidJoint modulesIMUBMSSim-to-Real

The Complete Robot Joint Module Selection Guide: Harmonic, Planetary, RV, Cycloidal & Quasi-Direct Drive — Vendor Research and Configurations by Robot Weight Class

How should robot joint modules actually be selected? Drawing on 200+ joint-module/reducer entries in the RobotWorld knowledge base, product research on leading vendors (Harmonic Drive, Nabtesco, Leaderdrive, Laifual, Leadshine, EYOBOT, ZeroErr, JIECANG, CubeMars, ENCOS), and item-by-item verification of the supply chains behind Tesla, Unitree, UBTECH, AgiBot and Fourier, this guide systematically compares harmonic, planetary, RV, cycloidal and quasi-direct-drive (QDD) transmission routes on performance and cost, provides a torque-tier product cheat-sheet (0.5-200 N·m) and full configuration recipes by robot weight class (small <=25kg / mid 30-55kg / large 60-100kg), plus a practical pitfall-avoidance playbook.

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Joint modulesHarmonic reducersPlanetary reducersQuasi-direct driveHumanoid robots

Windouble KSG-32-160 Harmonic Joint Module

Windouble KSG-series KSG-32-160 harmonic joint module: 160:1 ratio, 800 Nm rated / 1600 Nm peak torque, 160 mm body, 22 kg, Φ55h6 output shaft. The highest-torque model in the series, for heavy-duty robot joints. Windouble is a Chinese national-level specialized 'little giant' enterprise focused on high-precision harmonic drives for robots.

COMPONENT

HarmonicJoint modulesHarmonic reducersWindouble

Windouble KSG-25-160 Harmonic Joint Module

Windouble KSG-series KSG-25-160 harmonic joint module: 160:1 ratio, 400 Nm rated / 800 Nm peak torque, 135 mm body, 11.5 kg, Φ42h6 output shaft. Suited to heavy-load robot joints. Windouble is a Chinese national-level specialized 'little giant' enterprise focused on high-precision harmonic drives for robots.

COMPONENT

HarmonicJoint modulesHarmonic reducersWindouble

Windouble KSG-20-120 Harmonic Joint Module

Windouble KSG-series KSG-20-120 harmonic joint module: 120:1 ratio, 180 Nm rated / 360 Nm peak torque, 105 mm body, 5.5 kg, Φ32h6 output shaft. Suited to medium/heavy-load robot joints. Windouble is a Chinese national-level specialized 'little giant' enterprise focused on high-precision harmonic drives for robots.

COMPONENT

HarmonicJoint modulesHarmonic reducersWindouble

Windouble KSG-17-100 Harmonic Joint Module

Windouble KSG-series KSG-17-100 harmonic joint module: 100:1 ratio, 85 Nm rated / 180 Nm peak torque, 80 mm body, 2.4 kg, Φ22h6 output shaft. Suited to small/medium-load robot joints. Windouble is a Chinese national-level specialized 'little giant' enterprise focused on high-precision harmonic drives for robots.

COMPONENT

HarmonicJoint modulesHarmonic reducersWindouble

Windouble KSG-14-100 Harmonic Joint Module

Windouble KSG-series KSG-14-100 harmonic joint module: 100:1 ratio, 40 Nm rated / 100 Nm peak torque, 70 mm body, 1.8 kg, Φ19h6 output shaft. Suited to light-load robot joints. Windouble is a Chinese national-level specialized 'little giant' enterprise focused on high-precision harmonic drives for robots.

COMPONENT

HarmonicJoint modulesHarmonic reducersWindouble

Kingly Motor JL-JM02

Kingly Motor (874716) JL-JM02 . Mechatronic integrated micro-transmission modules for service robots, humanoid hand/foot/head joints. High precision, long life, low noise.

COMPONENT

Joint modulesJinli IntelligentKinglyMiniature transmissionService robots

Kingly Motor JL-JM01

Kingly Motor (874716) JL-JM01 . Mechatronic integrated micro-transmission modules for service robots, humanoid hand/foot/head joints. High precision, long life, low noise.

COMPONENT

Joint modulesJinli IntelligentKinglyMiniature transmissionService robots

Shuanglin SL-JM01

Shuanglin (300100) SL-JM01 . Full-stack in-house R&D for linear joint modules and core components. 63 core components deployed across 13 customers. Precision drive technology for humanoid robot mass production.

COMPONENT

Shuanglin SharesShuanglinJoint modulesHumanoid

Shuanglin SL-LJM03

Shuanglin (300100) SL-LJM03 . Full-stack in-house R&D for linear joint modules and core components. 63 core components deployed across 13 customers. Precision drive technology for humanoid robot mass production.

COMPONENT

Shuanglin SharesShuanglinJoint modulesLead screwsLinear joints

Shuanglin SL-LJM02

Shuanglin (300100) SL-LJM02 . Full-stack in-house R&D for linear joint modules and core components. 63 core components deployed across 13 customers. Precision drive technology for humanoid robot mass production.

COMPONENT

Shuanglin SharesShuanglinJoint modulesLead screwsLinear joints

Shuanglin SL-LJM01

Shuanglin (300100) SL-LJM01 . Full-stack in-house R&D for linear joint modules and core components. 63 core components deployed across 13 customers. Precision drive technology for humanoid robot mass production.

COMPONENT

Shuanglin SharesShuanglinJoint modulesLead screwsLinear joints

Zhongda Leader ZD-JM03

Zhongda Leader (002896) ZD-JM03 . China's only manufacturer mass-producing harmonic/planar/cycloidal three reducer types. Integrated joint module with motor+reducer+encoder+drive. For humanoid, industrial, and collaborative robots.

COMPONENT

Joint modulesZhongDaLiDeZhongdaHarmonic reductionPlanetary reduction

Zhongda Leader ZD-JM02

Zhongda Leader (002896) ZD-JM02 . China's only manufacturer mass-producing harmonic/planar/cycloidal three reducer types. Integrated joint module with motor+reducer+encoder+drive. For humanoid, industrial, and collaborative robots.

COMPONENT

Joint modulesZhongDaLiDeZhongdaHarmonic reductionPlanetary reduction

Zhongda Leader ZD-JM01

Zhongda Leader (002896) ZD-JM01 . China's only manufacturer mass-producing harmonic/planar/cycloidal three reducer types. Integrated joint module with motor+reducer+encoder+drive. For humanoid, industrial, and collaborative robots.

COMPONENT

Joint modulesZhongDaLiDeZhongdaHarmonic reductionPlanetary reduction

Welling Robot Parts WL-HJM04

Midea Welling Robot Parts WL-HJM04 : peak torque density 100 N m/kg, power density 300 W/kg, integrated large-hollow design, force-position hybrid control. Harmonic/planar dual series for full-body humanoid robot joints. Adopted by leading global robot manufacturers.

COMPONENT

Joint modulesWeiling MotorWellingMideaHarmonic reduction

Welling Robot Parts WL-HJM03

Midea Welling Robot Parts WL-HJM03 : peak torque density 100 N m/kg, power density 300 W/kg, integrated large-hollow design, force-position hybrid control. Harmonic/planar dual series for full-body humanoid robot joints. Adopted by leading global robot manufacturers.

COMPONENT

Joint modulesWeiling MotorWellingMideaHarmonic reduction

Welling Robot Parts WL-HJM02

Midea Welling Robot Parts WL-HJM02 : peak torque density 100 N m/kg, power density 300 W/kg, integrated large-hollow design, force-position hybrid control. Harmonic/planar dual series for full-body humanoid robot joints. Adopted by leading global robot manufacturers.

COMPONENT

Joint modulesWeiling MotorWellingMideaHarmonic reduction

Welling Robot Parts WL-HJM01

Midea Welling Robot Parts WL-HJM01 : peak torque density 100 N m/kg, power density 300 W/kg, integrated large-hollow design, force-position hybrid control. Harmonic/planar dual series for full-body humanoid robot joints. Adopted by leading global robot manufacturers.

COMPONENT

Joint modulesWeiling MotorWellingMideaHarmonic reduction

Newgear NG-JM03

Newgear NG-JM03 . Integrated precision reducer + motor + drive. Solves joint module thermal, precision, and stiffness challenges. For humanoid, cobot, and industrial robot joints.

COMPONENT

Joint modulesNuegelNewgearHarmonic reductionPlanetary reduction

Newgear NG-JM02

Newgear NG-JM02 . Integrated precision reducer + motor + drive. Solves joint module thermal, precision, and stiffness challenges. For humanoid, cobot, and industrial robot joints.

COMPONENT

Joint modulesNuegelNewgearHarmonic reductionPlanetary reduction

Newgear NG-JM01

Newgear NG-JM01 . Integrated precision reducer + motor + drive. Solves joint module thermal, precision, and stiffness challenges. For humanoid, cobot, and industrial robot joints.

COMPONENT

Joint modulesNuegelNewgearHarmonic reductionPlanetary reduction

Huayan Robotics HY-HJM04

Huayan Robotics (01021.HK) HY-HJM04 . Integrated motor + reducer + encoder + drive. For humanoid robots, cobots, and robot dogs. Full range of harmonic/planar/linear joint modules.

COMPONENT

Joint modulesIntegrated jointsHuayan RoboticsHuayanHumanoid