Recently, there are increasing needs for high power micro actuators in order to downsize the mechatronics devices. The purpose of this paper is to design a new type of micro ultrasonic motor which has a micro encoder. This motor is a rectangular prism with side-lengths 2.6mm, 2.6mm and 9.8mm. The micro encoder mounted on the ultrasonic motor is a magnetic type. This micro encoder was united with a motor shaft and a magnetic drum has 10 poles by 0.43mm pitch. This encoder outputs 20 pulses every revolution. To evaluate this encoder, the revolution speed of the electromagnetic motor was controlled.
