Design and modeling of an amplified piezoelectric actuator based on compound compliant amplification mechanism

The development of compliant amplification mechanisms to enlarge the displacement of piezoelectric actuators with optimally kinetostatic and dynamic trade-offs continues to attract significant research interest. This paper introduces a compact compliant amplification mechanism for piezoelectric stacks based on a compound amplification principle that combines displacement summation and multiplication. A high displacement amplification ratio, along with enhanced load capacity and dynamic bandwidth, is achieved by optimizing design dimensions using a dynamic stiffness matrix formulation and the Pareto optimizing strategy, taking both kinetostatic and dynamic factors into account. Theoretical and numerical analyses confirm that the output displacement range, output stiffness, and master natural frequency of the proposed amplified piezoelectric actuator outperform those based on the traditional bridge- and rhombus-type flexure amplification mechanisms. Experimental evaluation of an actuator with dimensions of 65 × 26 × 7 mm3 produces a displacement amplification ratio of 10.5 and a master natural frequency of 969 Hz, exhibiting satisfying performance when compared with existing designs.