Design of a Nib-Shaped Ultrasonic Motor for Auto-focusing Camera

Abstract

In this paper, a newly designed nib-shaped ultrasonic motor was proposed. The motor can be easily designed and fabricated as a small actuator due to its simple structure composed of a nib-shaped elastic body frame and two ceramics. Also, the motor is expected to be used as small actuator for auto-focusing camera by designing the size of the motor less than 10[mm], because the ultrasonic motor has general merit of generating high torque in spite of low speed. When two sinusoidal sources with phase difference of 90 degrees are applied to two ceramics, the elliptical displacement is generated at contact tip of the motor. To define vibration shapes and output characteristics of the motor, design parameters were chosen and the modeling of the motor was conducted by using ANSYS 11.0, FEM(Finite Element Method) Program. Elliptical motions of the contact tips of the stator were consistently obtained at resonance frequency. Characteristics of the motor such as frequency, speed, torque, and pre-load were measured by using the driving system and measurement equipment. From the fabricated prototype motor, high rotational speeds were obtained by applying relatively low voltages. Speed and torque were increased linearly by increasing the voltage

Keywords:

• Ultrasonic motor
• Nib-shaped
• Elliptical displacement
• resonance frequency
• FEM
• ANSYS

Acknowledgments

This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (NO. 2011-0030806)

This work was supported by the Gyeongnam, Changwon Science Research Park Project of the Grant of the Korean Ministry of Education, Science and Technology(2011-0054)