A sandwich piezoelectric actuator with long stroke and nanometer resolution by the hybrid of two actuation modes

A piezoelectric actuator operating at direct actuation mode and inertial actuation mode was proposed for linear driving with long stroke, nanometer resolution and high scan rate. Different from the previous piezoelectric actuators constructed with stacked flexure structures, the proposed actuator used a sandwich structure with high resonance frequency. The operating principle was discussed. The structure was designed by the assistance of theoretical analysis and finite element simulation. A prototype was fabricated and its experiments were performed to investigate the characteristics. The resonance frequency of the first horizontal bending mode was measured to be 12,720 Hz by a scanning laser Doppler vibrometer. When operating at the direct mode, a displacement resolution of 12.5 nm was obtained and a maximum scan rate that was about 190 Hz with scan range of 3.685 mu m was achieved. When operating at the inertial mode, the prototype achieved the maximum output speed and thrust force of 14.44 mu m/s and 1.67 N under the voltage of 420 Vp-p and frequency of 15 Hz, respectively. The proposed actuator can achieve a long stroke by the inertial actuation mode and realize high frequency scanning of micron stroke with nanometer resolution by the direct actuation mode, it has good application prospects in the fields of nano scanning and biological manipulation. (C) 2019 Elsevier B.V. All rights reserved.