Modeling of magnetic shape memory based linear and rotary actuators that utilize strain wave gearing

Magnetic Shape Memory (MSM) based actuators have exhibited considerable potential in the domain of small-scale mechatronic applications. Nonetheless, the current generation of actuators that utilizes MSM alloys fails to fully harness the remarkable properties inherent to this material, resulting in severely constrained motion range and limited force output. In this article we propose novel actuators that integrate MSM elements and strain wave gearing (harmonic gearing). This approach enables the development of both linear and rotary actuators, characterized by substantially enhanced force output and expanded motion range, which is unlimited in the case of rotary motion. Several actuator designs are presented and simulated in closed and open-loop control. A closed-loop control algorithm is proposed. The simulations undertaken explore the influence of varied parameters on actuator performance, including the number of installed MSM elements, twin boundary type, and tooth profile. Based on theory and simulation results an optimal tooth profile is suggested.