Design, modeling, and experimental evaluation of a piezoelectric actuator based on four-stage magnifying mechanism.

This study designs a novel piezoelectric actuator (PA) and models and experimentally evaluates it, which improves the output stroke and driving efficiency. A four-stage magnifying mechanism with an ingenious structure is utilized to magnify the displacements of the piezoelectric material stacks. Rhombic, lever, triangular, and lever mechanisms form the four-stage magnifying mechanism. The proposed PA has two driving feet, and a guide rail is driven to move twice within one driving period under the proposed working principle. This structure and principle allow for large stroke, high velocity, and highly efficient driving. Theoretical model and finite element analysis are created to determine magnification ratio and optimize structural design. Experiments including step performance, load performance, and the influence of pretightening force on output performance are conducted. A maximum driving velocity of 11.34 mm/s is obtained through experiment. The resolution and maximum load capacity is tested to be of 120 nm and 0.25 N, respectively. This study has developed a long stroke, high-velocity, and high-efficiency linear PA with a relatively simple structure and working principle.