Grasshopper Hindleg Mechanism-Inspired Bionic Miniature Stick-Slip Piezoelectric Actuator With High-Speed Performance

The demand for high-speed motion capability of miniature actuators continues to grow across industrial and scientific applications. Inspired by grasshopper hindleg mechanisms, this article presents a bionic miniature stick-slip piezoelectric actuator with high-speed motion. Through dual optimization of the stepping displacement amplification ratio and operational frequency bandwidth, the actuator achieves a breakthrough in speed enhancement. A displacement coupling amplification structure is employed to enhance the forward displacement during the stick phase, and the stick-slip and impact inertia coupling mechanism of the actuator effectively suppresses backward motion during the slip phase. The mechanical structure and driving principle of the actuator are systematically investigated, and the efficacy of the flexure hinge mechanism is demonstrated conclusively through matrix-based compliance modeling (MCM) and finite element modeling (FEM). The dimensions and weight of the actuator are determined to be 26 mm$\boldsymbol{\times}$20.2 mm$\boldsymbol{\times}$5 mm and 5.75 g, respectively. Experiments show that the actuator reaches a maximum speed of 117.19 mm/s at 150 V and 5.5 kHz, and the maximum horizontal load capacity is 250 g, which is 43.5 times of its own mass. These features endow the actuator with promising application in the field of miniature robots.