METHOD FOR DETECTING POSITION OF ULTRASONIC MOTOR

摘要

PURPOSE:To achieve a speed control with an improved accuracy and writing/ reading of data to and from a card and then enable cost down of a card reader using an ultrasonic motor to be promoted without using an encoder. CONSTITUTION:Piezoelectric ceramics 4-1-4-3 are buried and fixed into a transport rail 2-1 with a specified spacing in a traveling direction of a vibrator 1. Transport rails 2-1 and 2-2 vibrate slightly by receiving an ultrasonic elliptic vibration of the vibrator 1. When a roller 3-1 passes while being accompanied by traveling in a direction of A of the vibrator 1, the piezoelectric ceramics 4-1-4-3 generate an electromotive force where the amplitude fluctuates greatly according to a vibration of the transport rail 2-1 and a change in a surface contact pressure of the roller 3-1 due to the vibration. It is possible to examine which piezoelectric ceramic 4 generates a maximum electromotive force based on this electromotive force, thus enabling an area near the piezoelectric ceramic 4 which generates a maximum electromotive force to be a current traveling position of the vibrator 1.