Theoretical analysis and design of ultrasonic micromotors

Ultrasonic micromotor is a new kind of actuator in the field of MEMS (micro electro mechanical system). It overcomes the problems currently associated with other micromotors such as low torque output, large friction and the need for high voltage excitation. More importantly, it may offer a much simpler mechanism for creating mechanical power output. This kind of piezoelectric micromotor is much available for microrobots. So it may be one of the actuators which have good prospects. The authors have fabricated 4 ultrasonic micromotors with 3 mm in diameter and 5 mm in height. These micromotors consist of two parts: stators and rotors. This paper presents a new theory of contact friction to analyze the intrinsic quality of ultrasonic micromotors. Then the authors have done performance experiment of these 4 ultrasonic micromotors. The experiment results are basically identical to the theory analysis. Finally, the authors analyze the good performance of ultrasonic micromotor, and evaluate its broad prospects in the field of MEMS