Analysis Of A Longitudinal-flexural Mode Linear Ultrasonic Motor

Much theoretical and practical works on linear ultrasonic motors have been studied athome and abroad. They are characterized as simple mechanical construction,noelectromagnetic interference, direct drive, high positioning accuracy and without extraenergy consumption and so on, thus meeting the requirements of microminiaturizationprecision driving systems and applying to the robot, accurate positioning device, aviationspacecraft, etc. So, it has a wide application prospect. Now, several different types of linearultrasonic motors have been commercialized at abroad. However, the work on the linearultrasonic motors is far away from mature. Therefore, it is of great importance to spare noefforts to do more research on linear ultrasonic motors.The paper’s main contributions are as follows: Finite element model of the motor wasestablished. A serial of analysis including size adjustment, modal, harmonic responses,transient were made by using ANSYS software. Vibrating mode of the piezoelectricresonator was obtained with simulation. What’s more, the parameters of the correspondingdynamic branch equivalent circuit and the frequency of the vibration with longitudinal andbending mode were calculated. The elliptical trace of the piezoelectric stator was verifiedwith simulation. Besides, in order to observe the driving situation, contact analysis of alongitudinal-flexural model linear ultrasonic motors were made. Finally, when the size ofoscillator is38.2×9.6×1mm, the optimized speed of motors were obtained as76.4mm/swith the working frequency of33090Hz, the drive voltage of10V and the pre-pressure of13N.In this paper, comparison of the simulation was made in detail. On internal factors,there were many facts to influence the performance of linear ultrasonic motors, such asmaterials, structure. On external factors, there were also many facts, such as frequency, thedriving voltage and other factors. Finally, multilayer piezoelectric ceramic motors havebeen researched with their advantages of low voltage and small size. When the size ofoscillator is6.3×1.64×0.1mm, the optimized speed of motors were obtained as511.6mm/swith the working frequency of200kHz, the drive voltage of1V and the pre-pressure of7N.