Next-Generation Humanoid Robot Joint Design: HONPINE HPJM with Harmonic Drive, Hollow Shaft, and Integrated Encoder Module

From May 8 to 11, 2026, the 22nd Zhengzhou Industrial Equipment Expo (ZIF) was grandly held at the Zhengzhou Zhongyuan International Convention and Exhibition Center (Airport Zone). As one of the highlights of the robotics exhibition hall, HONPINE showcased its latest HPJM Integrated Joint Module series.

Structural Features of the HONPINE HPJM Integrated Joint Module

The latest humanoid robot joint module presented by HONPINE demonstrates a highly integrated structural design philosophy. The core concept of the integrated joint module is the deep integration of six core components into a single compact unit, including:

• Driver

• Frameless torque motor

• Reducer

• Brake

• Encoder

• Sensors

Based on this architecture, HONPINE further developed a modular platform strategy. By offering more than 50 different joint module specifications, the platform enables flexible development of robotic systems with varying performance levels and cost structures, significantly reducing the development barriers for humanoid robots.

From the perspective of reducer technology, the showcased joint modules are divided into two main technical routes:

Harmonic Drive Solution (PRO Series)

The PRO Series adopts a self-developed ultra-thin harmonic reducer featuring:

Compact structure

High power density

Optimized design for upper-body precision operations and load requirements in humanoid robots

Through flexible gear optimization and material innovation, the system addresses common issues found in traditional harmonic reducers, including:

Large size

Excessive heat generation

Limited service life

Thermal Management and Hollow Shaft Cable Routing Design

The joint module is equipped with a highly efficient heat dissipation structure to prevent performance degradation caused by overheating.

Meanwhile, the HPJM series adopts a hollow-shaft cable routing design with a hollow ratio exceeding 11%.

The new-generation product achieves a large 31.5 mm hollow bore within a compact outer diameter of 120 mm, greatly facilitating cable routing and effectively reducing cable wear. This design fully meets the stringent requirements of humanoid robots for wiring convenience and operational reliability.

Encoder and Brake Technology

HONPINE’s self-developed 24-bit dual-encoder solution, combined with multi-turn absolute encoder power-loss memory functionality, allows the robot to accurately retain joint position information even after power shutdown and restart, eliminating the need for re-zero calibration.

This feature is particularly important for high-precision robotic applications.

The salient-pole magnetic circuit permanent magnet brake design integrates the motor and brake into a single structure, saving axial installation space while simultaneously increasing braking torque, further improving joint safety and reliability.

Performance Parameters of the HONPINE HPJM Integrated Joint Module

Peak Torque Density

The new-generation joint module achieves a peak torque density of:

192 Nm/kg

This parameter directly determines the robot’s explosive power and dynamic performance, serving as the foundation for advanced motions such as:

• Running

• Jumping

• Dynamic balancing

• Hollow Bore Diameter

Within the compact 120 mm outer diameter structure, the module integrates a large 31.5 mm hollow bore, significantly improving cable routing convenience and system integration flexibility.

Weight and Volume Optimization

Compared with traditional solutions:

Weight is reduced by more than one-third

Overall energy consumption is significantly lowered

Volume is optimized to the extreme under the same torque output

This provides much greater flexibility for complete robot structural design.

Encoder Accuracy

The module is equipped with a self-developed 24-bit dual encoder featuring:

• Multi-turn absolute position memory

• High positioning accuracy

• Excellent motion smoothness

It is fully capable of handling:

• Precision operations

• Smooth motion control

• Complex robotic movements

Application Scenarios of the HONPINE HPJM Integrated Joint Module

Based on its self-developed lightweight joint modules, HONPINE products have already been deployed in multiple humanoid robot platforms.

For example, one humanoid robot equipped with HONPINE joint modules features:

• Height: 1.7 meters

• Total degrees of freedom: 44

• Total weight: only 48 kg

• Single-arm payload capacity: 5 kg

This demonstrates an exceptionally high payload-to-weight ratio.

Industrial Automation Applications

In industrial automation, the PRO Series joint modules have been widely adopted in lightweight collaborative robot systems, meeting requirements such as:

• High repeatability accuracy

• High flexibility

• Rapid deployment

Contact HONPINE to obtain more information and technical documentation about HPJM robot joint modules.