碟型壓電馬達之結構動態分析

Abstract

本文主要是應用有限元素分析軟體ANSYS 5.5，對於行波型壓電馬達的碟型定子進行動態分析。壓電馬達的定子是由壓電陶瓷與線彈性金屬圓板粘接而成，當壓電陶瓷受到頻率接近定子自然頻率的時諧電壓激發，其側向收縮會使定子產生彎曲變形之共振。時諧電壓對於壓電陶瓷上各個分佈電極依次作用而產生一行波，使定子運動軌跡呈一橢圓，並藉摩擦作用驅動轉子旋轉。本研究先對定子作模態分析，計算出各種模態下的自然頻率與振型；然後，對一個雙波長模態之定子作暫態分析，觀察定子在時諧電壓作用下的暫態面外位移及自靜止狀態啟動的動態行為。

This thesis studies dynamic behavior of the disk-type stator in a travelling wave piezoelectric motor using a commercial finite element code, ANSYS ver. 5.5. The stator of piezoelectric motor is made of a set of piezoceramic films mounted on a linearly elastic metal substrate. As the piezoelectric elements are excited by an alternating current in a frequency near the resonant frequency of the stator, the resulting lateral extension/shrinkage of the piezo-elements induces flexural deformation in the stator. The bending of the stator causes off-midplane points to move in an elliptical trajectory. The rotor is then driven via contact frictional forces by flexural waves excited on the stator. Modal analysis of the stator was carried out in this research to evaluate the resonant frequencies and their corresponding normal modes. Further, transient responses of a two-wavelength mode stator excited by time-harmonic voltages were investigated. The time-dependent out-of-plane displacement of the stator was calculated and compared with the static flexural deformation to understand its performance of revolution from rest.