Design of Roll-Screen System Using Ultrasonic Motor

For silent operation, Roll-Screen has been designed by using piezolelectric ultrasonic motor. To drive the ultrasonic motor, a digitally controlled drive system has been designed by using PLD. And to measure the position and velocity of Roll-Screen, encoder with 36 pulse/revolution is used. This paper proposed a new method for a precise velocity control of ultrasonic motor, in spite of using low-level encoder. The proposed method use a non-fixed sampling time and compensate the initial nonlinear characteristics of ultrasonic motors.