A Novel Force-Couple SMA Rotary Actuator for MEMS Safety and Arming Device

This paper presents the conceptual design, operating principle, geometric model, finite element method (FEM) analysis, and working performance verification of a novel force-couple rotary actuator using shape memory alloy (SMA). The rotary actuator is developed for micro-electromechanical system (MEMS) safety and arming devices (SAD). To achieve the goal, a rotary actuation mechanism is devised based on lever principles combined with rotational principle of force couple. The rotary actuator can convert the state of the SAD from the safety to arming by the mechanism. FEM simulations combined with experiments confirmed its feasibility for MEMS SAD. With a current of 3.2A, the rotation angle is up to 22°, the displacement of the planar SMA actuation element is 0.38mm and the target displacement is 1.8mm. In this study, the shape memory effect was actuated via Joule heating generated by direct electrical current excitation. This work provides new insights into SMA applications in MEMS SAD, further advancing the SAD field.