Driving Characteristics of the Thin-Type Ultrasonic Motor Using Microcontroller

Abstract

This paper represented driving characteristic of a thin-type ultrasonic motor by fabricating and utilizing two kinds of drivers which could generate sinusoidal wave, square wave, respectively. A thin brass plate was used as a cross shaped vibrator and sixteen ceramic plates were attached on upper and bottom side of the brass plate. From the thin stator, elliptical displacements of the four contact tips were obtained. When two harmonic voltages which have 90° phase difference were applied to the ceramics, the symmetric and anti-symmetric displacements were generated at inside of the tips to make the elliptical motion. A finite element analysis (ATILA) was used for simulating the motional pattern of contact tips of the stator. The characteristics of the motor such as speed, torque, and current consumption were measured by applying sinusoidal waves through driving equipment which composed of function generator and power amplifier. As a result, the speed and the torque changed linearly at both driving frequency of 88.6 ∼ 87.6[kHz] and voltage of 24∼36[V]. Two-drivers which generate sinusoidal waves and square waves were designed and compared through some experiments in order to be put to practical use. In conclusion, the drivers had similar characteristic of speed-torque at alike frequency and voltage range. The square wave driver was recommended to control the motor linearly among two drivers by reason of practical use and simplification of driver.