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The ultrasonic motor(USM) is due to the structure, high precision and quick response and no electromagnetic interference, and many other advantages, has become the attention of scholars at home and abroad. Currently, the most mature and practical motor, the traditional patch-type traveling wave USM and the fashioned traveling wave USM using ceramic transducer, due to the limitations of working principle and unreasonable structure, have certain defects.This paper analyzes the disadvantages of the two kinds of afore-mentioned motor, puts forward a new kind of ultrasonic driver composed by four longitudinal transducer and four driving feet located of both the end points of transducer. The ultrasonic driver retains the efficient d33 coupling mode. Breaking through the traditional thinking of motor is driven by circular wave, the ultrasonic driver is designed based on four transducer composite structure, with four feet driving the rotor directly. The ultrasonic driver not only have more simple and compact structure, also have higher energy conversion efficiency and stronger driving torque.To examine the feasibility of the scheme, this paper theoretically analysis on ultrasonic driver. According to the idea of from the modal analysis to the modal synthesis, this paper discusses composite work modal of the ultrasonic driver, explores the principle of stimulating this work modal, motion equation, deduces the motion equation of the particle on driving foot, verify the oval tracks which have good ability to drive rotor, combining the working mode and driving foot trajectory to investigate the vibration of ultrasonic driver in a cycle of motivation, confirms that all driving feet have driving ability in phase, proved the feasibility of the ultrasonic driver scheme in theory.Based on the finite element analysis software, simulation research is conducted to determine the exact dimensions of the ultrasonic driver. On the basis of theoretical analysis, through the modal analysis and transient analysis of longitudinal transducer, its size parameters are determined; To meet the requirement of special structure and pre-tightening, the saw-tooth-shaped spring pieces are designed, and by static analysis, all its serrated parameters can be determined; Finally, establish the finite element model of the ultrasonic driver, and produce modal analysis, transient analysis, and the harmonic response analysis. Simulation results determine the sizes of each part of ultrasonic driver eventually.This paper makes a prototype, and analyses the impedance matching, build a simple test platform for measuring the various mechanical characteristics of prototype, verifies the correctness of theory analysis and simulation, and according to the deviation of measurement results and theoretical analysis and simulation, discusses the reasons.
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