A grasshopper-inspired miniature piezoelectric actuator integrated with three vibrating units

Miniature piezoelectric actuators (MPAs) have been extensively investigated owing to their gram-scale mass, sub-micrometer resolution, and milliwatt-range power consumption. However, improving their output characteristics (force, speed, resolution) while maintaining miniaturization remains challenging. In this study, a three-vibrating-unit MPA (3VU-MPA) was proposed, which consists of three vibrating units (VUs) and two integrated vibration isolation mechanisms (VIMs). The design of the VIM was analyzed using the transfer matrix method and finite element analysis. The VIM design enables the 3VU-MPA to work in three working modes: individual excitation, alternating excitation and cooperative excitation. A prototype was fabricated and experimentally evaluated, measuring 15.4 × 15.6 × 30 mm³ and weighing 4.7 g. A maximum speed of 351.8 mm/s was achieved by the 3VU-MPA under no-load conditions, while a maximum payload capacity of 203.5 g was obtained at reduced speed. A maximum speed of 197.7 mm/s was achieved with a traction force of 46.1 mN when climbing vertical rods. Additionally, a displacement resolution of 0.15 μm was obtained. This work provides a feasible approach to enhance both output performance and working mode diversity in MPAs.