Introduction
Modularity decides whether a humanoid is a sealed product or a platform that can evolve. A useful module boundary defines mechanical mounting power communication timing safety identity and calibration. Without those contracts a hand or joint can fit physically and still be impossible to use safely.
Key facts
- China started a national project for general humanoid modularity requirements in 2026.
- A separate Chinese project covers mechanical electrical and communication interfaces for integrated joints.
- ISO 9409 defines established mechanical interfaces for robot end effectors.
Mechanical compatibility is only the first layer
Bolt pattern dimensions load capacity stiffness alignment and cable routing determine whether a module can be attached. The interface also needs repeatable positioning so calibration does not change every time a hand or tool is removed. Existing industrial standards show how mechanical interface definitions can support exchangeability.
Power interfaces need clear operating envelopes
Voltage current peak power grounding connector retention and fault behavior should be explicit. A module that pulls more current during a fast grasp can disturb the rest of the robot if the power system is not designed for the transient load. Safe removal and insertion also need rules.
Communication must describe timing and meaning
A raw bus connection does not create interoperability. Devices need agreed message definitions units update rates timestamps error states firmware identity and discovery. China has a separate humanoid body communication interface project which shows that communication is being standardized alongside mechanics.
Software needs capability discovery
Higher layers should be able to learn which joints sensors or end effectors are installed and what commands they support. A modular robot also needs version compatibility and calibration data that travel with the module. This reduces hard coded assumptions inside every skill.
Modularity changes maintenance economics
A field replaceable hand or joint can shorten downtime but only when the replacement process is documented and repeatable. Teams should measure swap time calibration time validation steps spare inventory and whether a replacement can be completed by site staff without factory support.
Limitations and missing information
- A module standard does not guarantee identical performance across vendors.
- Load and safety limits can change after a module swap.
- Calibration is part of the interface even when it is handled in software.
Conclusion
Modular interfaces can reduce integration cost and make humanoid platforms easier to repair. The practical value appears when a component can be replaced without a long mechanical software and calibration project.
Sources and methodology
This guide separates published standards and official technical documents from engineering practice. Draft standards are described as work in progress. Product capability is not treated as verified unless a source supports it.
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