Study On The Application Of Ultrasonic Motor In Inner End Door Of High-speed Railway Vehicle

Ultrasonic motor is a new type of motor driven by piezoelectric materials,it has many characteristics such as low speed,high torque,fast response,no electromagnetic interference,no noise and so on.Taking the ultrasonic motor as the basic research object and the inner end door of the high-speed railway vehicle as the main application case,this research has a reference significance for the practicality of the ultrasonic motor and the re-innovation of the high-speed train.The analysis and design process of the ring traveling wave type ultrasonic motor is discussed systematically,including operation mechanism analysis,stator resonance frequency solution,driving circuit analysis and design,etc,at the same time,a physical driving board is made,and the actual operation waveform of the driving circuit is analyzed in detail.The driving board is successfully used to drive the prototype of the ultrasonic motor.The main research contents and achievements are as follows:1.The analytical solution process of stator resonance frequency is deduced.The annular stator can be regarded as a composite beam structure,the calculation program of stator modal frequency and modal shape is programed by using of the beam vibration modal theory and C language.The calculation results show that the 7-order analytical modal frequency of typical stator sample is 37784Hz,which is in accordance with the stator driving frequency of ultrasonic motor.2.Finite element modal analysis of typical stator is carried out by using ANSYS software.Based on the calculation results,the selection method of stator modal of ultrasonic motor is discussed.The stator size of Canon's 60 mm diameter ultrasonic motor is surveyed and mapped,the geometric model of the stator is established.The modal frequencies of the stator are calculated by finite element method,the error between the calculated results and the actual frequencies is only 0.23%,this shows the feasibility and accuracy of the finite element analysis method.The modal frequencies of four kinds of stators with different specifications are compared and analyzed,and the rule between the stator size and the vibration modal frequencies is achieved.The influence of the stator dip angle on the modal frequency is calculated and analyzed,the results show that the resonance frequency can be corrected by changing the stator dip angle.The method of eliminating the stator support plate and using the support frame to restrict the circumferential degree of freedom of the stator is conducive to improving the space utilization rate.3.The LC resonant boost drive circuit is simulated and analyzed by using of Multisim software.The results show that the duty cycle of driving signal can effectively change the amplitude of driving voltage,this method can be used in motor speed control.Based on STM32F429 development board,the acquisition method of driving signal and some software codes are analyzed,the physical driving board is made and its driving wave is collected andanalyzed by oscilloscope.The influence of component parameters on the experimental results and the cause of abnormal noise in the driving process are further discussed,the solution is given,it is a good supplement to the current research on the driving circuit of resonant boost type ultrasonic motor.4.According to the reality of high-speed railway vehicle,a kind of ultrasonic motor which can be used to control the inner end doors of vehicles is designed,and the design drawings of the main parts are given.The sensor arrangement,speed and rotation detection methods are explained,and some problems that may be encountered in the actual work of the inner end doors of vehicles are briefly described.This research also has application prospects in other field of vehicle equipment control.