Magnetic Gear Based Actuator: Design and Optimization

This paper proposes a mechanical design and a torque optimization procedure for a coaxial magnetic gear-based actuator module for robotic applications. While conventional mechanical gears have to accompany mechanical contact to transmit the power, the coaxial magnetic gear transmit the power in a non-contact manner. This non-contact power transmission has merits in terms of backdrivability and transparency. Moreover, its characteristics give attractive features such as transmission ratio amplification, overload protection, and spring-like behavior. These features ensure hardware safety and estimate the external torque using the phase difference between the inner and outer rotor like a series elastic actuator. However, designing proper magnetic gear for robotic applications is still challenging due to a low torque transmission capability. We chose several design parameter and conducted design optimization procedure based on Differential Evolution algorithm. The magnetic gear-based actuation module is implemented and its performance is evaluated by experiments.