A bionic stick-slip piezoelectric actuator based on the foreleg of an assassin bug

Abstract This paper presents a bionic stick-slip piezoelectric actuator inspired by the motion mechanism of the foreleg of an assassin bug. By combining a lever amplification mechanism with a pull-back structure, the actuator achieves unidirectional rotation without backward motion. The study includes the structural design, working principle analysis, dynamic modeling, simulation-based optimization, and experimental validation. The actuator measures 94 mm × 93 mm × 26.5 mm and is driven by a symmetric triangular wave voltage. Finite element analysis was employed to optimize the flexure hinge parameters, ensuring a high displacement amplification ratio and low stress concentration. Experimental results show that the actuator operates stably without backlash under both high and low driving voltages. At 135 Hz with PZT-1 driven at 80 V and PZT-2 at 100 V, the maximum angular velocity reaches 12.47 rad s −1 . Under lower voltages (20 V for PZT-1 and 50 V for PZT-2), the optimal frequency is 341 Hz, yielding an angular velocity of 11.03 rad s −1 . Load tests confirm that the actuator maintains satisfactory performance under a 30 g load, though the output declines under heavier loads. The proposed design offers a simple structure, large travel range, high resolution, and strong load capacity, demonstrating promising potential for applications in precision manufacturing, aerospace, and biomedical devices.