Theoretical And Experimental Study On A Disk-Pivot Structure Piezoelectric Micro Motor

Piezoelectric ceramics with large power density have been used as transducer in the piezoelectric micro motors, which can get higher efficiency and output torque. Therefore, new types of piezoelectric micro-motors have been the focus of research field. It can be applied in the fields of precision instrument, bioengineering and other micro actuate systems.A new type of piezoelectric micro-motors has been designed and tested in this article; a disk-pivot structure has been used to amplify the displacement on the disk under the vibration mode with 1 node diameter. The part of transducer has been optimized. An evaluation system has been build up composed of the resonance frequency and the amplified coefficient of displacement D. A laser test method was used to measure the high rotation speed of the micro piezoelectric motor.A predigested model has been made, and the parse result of the vibration modes in such a thin disk model has been obtained. FEM (Finite Element Method) was used in the modes and resonance analysis, the numerical result has been obtained. The author made an optimizing analysis of the transducer by FEM. The effect of modes coupling and the frequency separation from one vibration mode were studied. The optimized structure parameter was analyzed, the thickness of the stator disk is 1 mm, and the length of the mid-cylinder is 3.5 mm.The piezoelectric micro motor has been fabricated. It can work very well as the previous theoretical design. When the stimulation voltage is 100 Vo-p, the rotation speed can be up to over 104 rpm. This is much larger than any other piezoelectric micro motor reported in the references. The start-up process of the piezoelectric motor has been studied, and the start-up output torque has been calculated as 98μNm.