| Summary: | 碩士 === 國立雲林科技大學 === 機械工程系 === 104 === Generally, actuator can be classified as two forms, one is piezoelectric actuator, and the other is electromagnetic actuator. Moreover, standing wave type and traveling wave type are two major types of piezoelectric actuators. In this paper, converse piezoelectric effect occurs as we input voltage and driving frequency in piezoelectric plate. Piezoelectric effect is a phenomenon about mechanical energy transformation. We excite electrode to generate ultrasonic vibration that cause rotor to drive in elliptical motion and make stator start to move.
The purpose of this study is using standing wave type method to drive stator. The three piezoelectric actuators are attached to the foundation of fixture above the base that arrange asymmetrically and separate in 120 degrees. Besides, we can adjust the distance of fixture based on the size of rotor. The powerful magnet below the center is to increase the weight of stator by means of magnet suction. To increase the efficiency of piezoelectric plate, we must find the location of the fixture and the friction elements on the piezoelectric ceramic chaps by using finite element analysis software. The optimal driving frequency in mode(1,0), mode(0,1)and mode(1,1) is 194 frequency, 195 frequency and 191 frequency.
The structure of the two degrees of freedom piezoelectric actuators consist of three asymmetrical ceramic chaps, fixtures, friction elements, foundation of fixture, acrylic base, and rotor. There are three major situations about driving modes. In the first driving mode(1,0), the rotor applies a clockwise rotation around the y – axis with the highest speed as 54.2rpm. In the second driving mode(0,1), the rotor applies a anticlockwise rotation around the y – axis with the highest speed as 40.1 rpm. In the third driving mode(1,1), the rotor rotate around the x – axis with the highest speed as 26.6 rpm.
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