The ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide the motive force. (In conventional electric motors the motive force is electromagnetic). The result is a motor with unusually good low-speed high-torque and power-to-weight characteristics. It has already found applications in camera autofocus mechanisms, medical equipment subject to high magnetic fields, and motorized car accessories. Its applications will increase as designers become more familiar with its unique characteristics.

This book is the result of a collaboration between the inventor and an expert in conventional electric motors: the result is an introduction to the general theory presented in a way that links it to conventional motor theory. It will be invaluable both to motor designers and to those who design with and use electric motors as an introduction to this important new invention.

Readership: Electrical and electronic research engineers interested in electric motors/actuators both academic and in industry.

Toshiiku Sashida, Managing Director, Shinsei Industries, Japan, and Takashi Kenjo, Professor, Department of Electrical Engineering and Power Electronics, University of Industrial Technology, Kanagawa, Japan

1: What is an ultrasonic motor?
2: Theoretical treatment of component elements
3: The Piezoelectric element and vibrator
4: Theory and experiments on the wedge-type motor
5: Theory of the ultrasonic wave motor
6: Equivalent-circuit analysis for the travelling-wave motor
7: Design, assembly and testing of a prototype ultrasonic motor
8: Comparison with electromagnetic motors
Autobiographical notes (Toshiiku Sashida)
Index