Topology optimization study of piezoelectric rotary actuator based on viscous slip principle

Abstract To enhance the structural performance and motion stability of stick–slip piezoelectric actuators under complex loading and frictional conditions, this study proposes a line-contact rotary stick–slip piezoelectric actuator designed via topology optimization. The actuator’s operating principle is first presented. A stiffness-uncertainty-aware topology optimization framework is then established to optimize the driving structure, and the optimized design is further examined through frictional dynamic analysis. Finally, a prototype is fabricated and experimentally validated, with a comprehensive performance comparison conducted from four perspectives: output angular displacement, rotational accuracy, load adaptability, and motion stability. The results demonstrate that the optimized actuator exhibits a markedly reduced standard deviation in stepwise angular displacement, accompanied by a significantly smoother motion response. Although the speed reduction rate increases as the load rises, the backward slip (recoil) ratio is significantly suppressed, leading to a more stable overall output; in particular, the minimum reverse displacement is observed at a load of 50 g. These results confirm the efficacy of the proposed topology-optimization-based design strategy and provide new theoretical and experimental evidence for structural design and performance enhancement of stick–slip piezoelectric actuators.