Theoretical and experimental study on a piezoelectric linear motor driven by multi-integer-frequency multi-mode method

Abstract

In this paper, we report a non-prismatic one-dimensional piezoelectric linear motor driven by a new method called “Multi- Integer-Frequency Multi-Mode.” The non-prismatic structure of the piezoelectric linear motor is constructed by a 180mm long by 17mm wide by 0.4mm thick stainless steel plate with two30mm long by 17mm wide by 0.6mm thick PZT actuators attached on the top and bottom of the stainless steel plate on two ends. To enable multiple bending modes can be superimposed equally, the ratio of driving voltage and the phase difference between modes are designed to make all of activated modes to have similar amplitudes. Thus, we can activate multiple bending modes for generating traveling waves on the piezoelectric motor. Furthermore, the driving frequencies are made to have a relationship of integer multiplication, and it can improve the efficiency of traveling wave generations. Applying this concept, we developed analytical and a simulation method to analyze the formation of traveling waves. It was identified numerically and verified experimentally that traveling waves can be excited by using the first to the fourth bending modes. We also introduced Hilbert Transform as the design tool for driving optimization and successfully found the most efficient traveling wave driving parameters. Using identified parameters, traveling waves were sufficient induced to push a 5.6g object on the piezoelectric motor in the region between 69.7mm and 122.6mm with an average velocity of 3.1mm/s.