Design and experimental investigation of a low-frequency resonant piezoelectric motor featuring a triple-rhombic flexure-based displacement amplification mechanism

Abstract

Precision micro-displacement systems require actuators capable of rapid, stable, controllable, and high-resolution motion. Piezoelectric motors capable of low-frequency resonant operation and quasi-static actuation are attractive for such systems: low-frequency resonant operation enables fast motion while reducing the demand for high-frequency excitation sources and mitigating high-frequency-related losses and heating, whereas quasi-static actuation provides fine displacement regulation for high-resolution positioning. This paper proposes a low-frequency resonant piezoelectric motor with a triple-rhombic flexure-based displacement amplification mechanism, and the motor can also be operated under quasi-static excitation. The stator integrates one central expansion-type rhombic unit and two lateral contraction-type rhombic units to generate the tangential driving component and normal contact modulation, respectively. Finite element analysis is used to guide target-mode matching. The resulting coupling enables the two driving feet to alternately drive the slider through frictional contact. At 40 Vpp, 3.95 kHz, and a preload of 16.5 N, the prototype achieves a maximum no-load speed of 62.15 mm s−1, carries a maximum load of 130 g, and shows a displacement resolution of 0.95 nm. These results demonstrate the potential of the proposed motor for precision micro-displacement applications in integrated-circuit manufacturing, inspection, and packaging.