A stick-slip piezoelectric actuator designed via the asymmetric friction

This paper proposes an asymmetric friction driving method to address the backward motion issue of stick-slip piezoelectric actuators. The optimization of the driving foot is conducted using the flexibility matrix and finite element simulation method. A general dynamic model of the asymmetric frictional stick-slip piezoelectric actuator is developed to validate the feasibility of the proposed method. Additionally, the dynamics model is utilized to analyze the smooth motion mechanism. A prototype is manufactured and tested, with experimental results demonstrating that the new piezoelectric actuator achieves smooth motion. Compared to traditional stick-slip piezoelectric actuators, which typically exhibit a backward motion rate of more than 5%, the displacement of the proposed actuator shows no backward motion when the driving voltage is increased from 25 V to 125 V. This result verifies the effectiveness of the proposed method. Furthermore, this actuator features a compact structure and offers high motion stability, operating smoothly at low driving voltages and frequencies. These findings lay a theoretical and experimental foundation for future research and expand the potential applications of stick-slip piezoelectric actuators.