| The characteristics of contact driving state between vibrator of ultrasonic motor and friction material on slider are high frequency, micro-amplitude and intermittent contact. This problem has been difficult in modeling and simulating because the high-frequency micro-amplitude contact characteristics of standing wave ultrasonic motor (SWUSM) share the same feature with single tooth traveling wave ultrasonic motor (TWUSM) driving rotor, and therefore simulating study on driving principle of vibrator of SWUSM is of great significance for revealing high-frequency friction principle of ultrasonic motor, instinct characteristics of friction materials and developing new type of friction materials. This paper makes a systematic research on driving models, element simulation, anisotropy theory, material preparation method and experiment testing technique.According to longitudinal and flexural vibration equations of a rod-ban shaped vibrator, the periodical motion law of ellipse on the tip of vibrator is deduced. From the contact characteristics between elliptical movement of vibrator tip and friction material of rotor, momentum conservation of piezoelectric vibrator in longitudinal direction is used to deduce relations between vibrator and contact angle of anisotropic friction material, preload and correlated physical parameters. Establish the dynamic model of rotor in transverse direction and through analysis of the horizontal vibrating velocity of vibrator and the output velocity of slider in steady mode, judge the direction of frictional force and relative velocity, in a cycle, to obtain velocity and equivalent thrust (load) equation, thus simulating the effects of preload and vibrator amplitude and friction material on load characteristics of SWUSM numerically.To solve multi-cycle problem, ABAQUS element software is used to simulate the characteristics of high-frequent contact and nonlinear deformation of friction material. Small elliptical particle rotating with high speed is used as longitudinal-flexural vibrator tip to simulate the high-frequent contact with friction material, and the related equivalent principle is argued. Among three driving model, analysis and calculation are carried out in terms of anisotropic material with different elastic constants and thickness, no-load speed of vibrator with different longitudinal-flexural vibrating amplitude, resistance and load characteristics.Based on longitudinal-flexural vibrating theory, an ultrasonic vibrator, which can generate high-frequent elliptical vibration microcosmically and be a driving machine macrocosmically, is designed. Test rig to support the ultrasonic vibrator is designed and high-frequent signal of dynamic force and data acquisition system are developed to provide support experimental condition for the test of friction material.Device and moulds for anisotropic friction material preparation are developed. Different angles between fiber and axis are used to change the anisotropy of friction material. Anisotropic friction materials with fiber angels of 0°, 15°, 30°, 45°, 60°, 90°are prepared. According to the microscopic mechanics theory of composite, engineering constants are calculated. In addition, based on the macroscopic mechanics theory of composite, the relation between stress and strain of monolayer composites along any direction and its engineering constants are also calculated. Furthermore, the engineering constants for two kinds of monolayer composites with 6 different angles are calculated. Finally, according to the stiffness theory of laminate, the engineering constants for two kinds of monolayer composites with 6 different angles are deduced.With the help of an ultrasonic micro driving tester, the driving characteristics of longitudinal-flexural vibrator and anisotropic friction material are tested and studied. The variations of longitudinal dynamic force and driving force of six kinds of axial fiber-angle materials are tested in terms of changing thickness, load and longitudinal- flexural exiting voltage. Micro driving principle of SWUSM is revealed by analyzing the wave shape of longitudinal and transverse driving forces in time domain. Through studying the amplitude of driving force and longitudinal normal force, friction and wear behavior of anisotropic friction material and copper vibrator tip are analyzed under different test conditions. As a result, material with fiber angle of 0°got the biggest driving force and longitudinal normal force. Consequently, load characteristic of anisotropic friction materials with 0°and 90°is further studied, and their friction driving models are.established, which well explain friction driving characteristic, properties of anisotropic friction material adapt to ultrasonic motor are acquired.
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