Optimal Friction Materials of Tiny Piezoelectric Ultrasonic Linear Motor In recent years, a novel tiny piezoelectric linear motor converting a radial mode vibration to a longitudinal mode vibration driven by the impact force has been developed for a camera optical module. The tiny piezoelectric motor is consisted of a shaft, mobile element,and piezoelectrictransducer.In the work, the frictional coefficient and static friction force of interface between the shaft andthe mobile element  have been investigated according to their respective materials. it was found that two combinations, exhibited good dynamic behaviors in the tiny ultrasonic linear motor, which was newly developed based on operating concepts based on Newton's law 형들 이거 지난번에 올렸던건데...부분적으로 빼먹은게 있어서... 다시 수정해서 올린거야...좀 부탁드릴께요...