Lightweight Humanoid Robots Start with Precision Transmission

Hello everyone, I’m Allen Li, Founder of HONPINE.

In this article, I would like to discuss the development and innovation of core components for humanoid robots, focusing on the trend toward lightweight humanoid robots, core transmission technologies, lightweight robot joints, and development kits.

From “Moving” to Long-Term Stable Operation: Higher Requirements for Robot Joints

As embodied intelligence and humanoid robots continue to develop rapidly, robots are moving beyond basic mobility toward lighter weight, higher efficiency, greater flexibility, and improved reliability.

In my view, weight, energy consumption, response speed, and continuous operating capability are becoming increasingly important factors in bringing robots into practical applications. Ultimately, these requirements are reflected in every individual joint.

For humanoid robots, a joint must provide sufficient output performance while balancing weight, dimensions, rigidity, precision, and service life within a limited structural space. As robots move toward lighter overall weight, higher torque density, and more natural movement, the core transmission components inside each joint are also facing increasingly demanding requirements.

Lightweight Design Starts with the Core Transmission

The relationship between a reducer and overall joint performance can be considered from five dimensions: weight, size, rigidity, precision, and service life.

Reducing the weight of the reducer can directly reduce the mass and motion inertia of the robotic arm. Outer diameter, axial length, and hollow-shaft dimensions affect the overall structural envelope of the joint. Transmission rigidity, precision, material selection, tooth profile design, and manufacturing consistency further influence motion stability and long-term reliability.

These factors form the starting point for HONPINE's continued development toward lightweight humanoid robot joints.

Over the years, HONPINE has continued to invest in the development of harmonic reducers, focusing on tooth profile design, materials and manufacturing processes, flexsplines, bearings, and structural integration. We have also established an integrated capability covering independent design, precision manufacturing, inspection, and volume production.

Today, more than 70% of our workshop production processes are automated. Except for flexspline hot forging, other major processes are completed in-house. Through temperature-controlled precision machining, critical tooth profile processing, and inspection processes, we work to maintain consistent product performance throughout production.

From Reducers to Robot Joints: Extending Core Technology into Applications

Based on our accumulated expertise in precision transmission, HONPINE has further extended its technology into robot joint development.

By integrating a torque sensor into the harmonic reducer, we can address structural integration, rigidity, strain interference, signal routing, and temperature drift within a limited installation space. This provides a foundation for more compact joint structures with integrated torque sensing.

At the same time, HONPINE integrates its own harmonic reducers with frameless torque motors, dual encoders, drive systems, and communication interfaces to develop a series of lightweight harmonic robot joints.

The current product range has developed into a product matrix from TCHL-11M to TCHL-32H, covering different joint requirements from the wrist to the hip. Multiple mounting configurations and communication options, including EtherCAT and CAN FD, are also available to support different robot architectures.

One Core Technology, Multiple Levels of Development

As the humanoid robot industry develops rapidly, customers are adopting increasingly diverse approaches to core component development.

Some companies have comprehensive in-house joint development capabilities and primarily require a reliable, high-performance core reducer. Others prefer highly integrated joint modules to shorten the development cycle of the complete robot. There are also teams at the prototype, robotic arm, or algorithm validation stage that require a more complete and open development environment.

To address these different requirements, HONPINE is building three product forms around the same precision transmission technology: lightweight reducers, lightweight robot joints, and development kits.

The reducer provides the core transmission capability. The lightweight joint provides a more integrated system solution. The development kit further supports customers with testing, commissioning, motion validation, and secondary development.

This also reflects how HONPINE approaches the development of humanoid robot components. We did not enter the core component market simply by starting with joint integration. Instead, we started from precision transmission technology and are extending toward the application side according to the different development needs of robotics companies.

Deepening Precision Transmission for Robotics and Supporting Industry Innovation

From industrial automation equipment to collaborative robots, and now to core robotic components such as harmonic reducers, HONPINE has continued to build its technical capabilities around robot motion and precision transmission.

As the humanoid robot industry enters a new stage of development, HONPINE will continue to focus on precision transmission as a core technology while investing in independent reducer development, precision manufacturing, joint integration, and development support.

Our goal is to provide robotics companies with different levels of support, from core transmission components to integrated joints and application validation.

With precision transmission at the core, HONPINE supports the next generation of robotic innovation.