Dual Source Dual Frequency Drive and Modeling of Resonance type Piezoelectric Motors

Inhalt:
In a resonance drive type piezoelectric motor, there are oblique or elliptical microscopic movements on a stator that is in contact to a slider. Only tangential components of these movements contribute a microscopic movement of a slider through frictional interaction. Normal components of the microscopic movements cause the normal force to increase or decrease, which can alter friction conditions. Due to the nature of frictional coupling, movement of a slider has nonlinear characteristic. The same elliptical or oblique trajectory can create different amount of microscopic movements or in some cases no movement. In a recent study, we introduced modulated elliptical motion at the contact point of a stator to a slider by driving a resonance drive type motor with two driving sources with different frequencies. Difference between the two frequencies of the two sources was synchronized to servo sampling frequency of the controller. As a result, a smooth low velocity movement without generating unpleasant friction induced noise was obtained. In this work, using transient analysis feature of ATILA-GID finite element software, behaviour of the stator was simulated under dual source dual frequency driving condition. Fibreoptic laser vibrometer measurements under different driving conditions show that the resulting trajectory at the tip of the friction coupler is nothing but the superposition of the displacements generated by each driving signals at two different frequencies. Keywords: piezoelectric; motor; resonance; dual-frequency