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Comparative Analysis of High-Torque-Density Permanent Magnet Motors Having Similar Slot and Pole Numbers for Humanoid
Kun Bi1, Zhuoyi Chen2, Tianran He3
1School of Machinery and Transportation, Changzhou Vocational Institute of Industry Technology, Changzhou 213164, China.
Biomimetics (Basel, Switzerland)
|June 25, 2026
Summary
This study introduces a novel high-torque-density permanent magnet motor for robotic force control. Optimized slot/pole combinations enhance torque and efficiency in interactive robotic systems.
Area of Science:
- Robotics and Control Systems
- Electrical Engineering
- Mechanical Engineering
Background:
- Force control is increasingly replacing position control in humanoid robots for interaction tasks.
- High-back-drive-efficiency actuators with integrated motors and reducers are crucial for sensorless torque control.
Purpose of the Study:
- To propose and analyze a high-torque-density permanent magnet motor with an external rotor and internal planetary reducer.
- To optimize the motor's slot/pole number combination for maximum torque and torque density.
Main Methods:
- Introduction of various motor topologies based on slot/pole number combinations.
- Optimization of slot/pole combination for enhanced torque and mass density.
- Finite Element (FE) analysis to investigate torque characteristics and overload capability.
Main Results:
- The proposed external rotor structure with an internal planetary reducer enhances torque density and space utilization.
- Optimization identified a slot/pole combination maximizing torque and torque mass density.
- FE analysis confirmed the influence of slot/pole combination on torque and overload performance.
Conclusions:
- The developed permanent magnet motor design is suitable for advanced robotic force control applications.
- The study validates the effectiveness of the proposed design through FE analysis and experimental results.
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