A micro ultrasonic motor controlled by using a built-in micro magnetic encoder

The purpose of this paper is to design a new micro ultrasonic motor which has a micro encoder. This motor has a rectangular prism shape. The side length of the cuboid case´s base is 2.6 mm and the height is 9.6 mm. In addition, the micro encoder is mounted on the top of the ultrasonic motor. The encoder is a magnetic type. This micro encoder is unified with a motor shaft and a magnetic drum has 10 poles by 0.43 mm pitch. This encoder outputs 20 pulses every revolution. The performance of the magnetic encoder and motor has been evaluated. We have also controlled the revolution speed of the micro ultrasonic motor by using the built-in encoder.