Research On Spheroidal Untrasonic Motor Using Longitudinal-Bending Hybrid Vibration Modal

Ultrasonic motor is a new type of micro motor.It makes use of the inverse piezoelectric effect of piezoelectric ceramics to force the transducer to work,and then drives the rotor motion by friction.The utility model has the advantages of low speed,high torque,no electromagnetic interference,no noise,flexible structure,quick response.But at the same time,there are some shortcomings: the theory is not mature,the drive system is not perfect.In this paper,the finite element analysis and design method is used to design the whole motor,including the material properties and size parameters,and the transient analysis and harmonic response analysis are carried out by using ANSYS to ensure the rationality of the motor design.A new type of multi degree of freedom ultrasonic motor with four cantilever beam longitudinal bending mode is presented.The main tasks are divided into the following five parts:(1)Firstly,the structure of ultrasonic motor is put forward,and its working principle is analyzed,including how to add the excitation signal and how to rotate the motor rotor.The metal material and the energy conversion material piezoelectric ceramics were determined,and the piezoelectric ceramics were analyzed.(2)The finite element method is used to design the motor.The modal analysis is used to determine the size of the motor and the frequency of the longitudinal bending mode and the merging of the transducer and the stator cylinder.Through the harmonic response analysis and transient analysis,the resonance frequency of the motor is20945 hz.(3)Based on the design of the motor,the design of a universal motor drive power supply.The power supply comprises a frequency generator,a frequency shift phase shifter circuit,a signal amplifying circuit,an inverter and a matching circuit,a feedback control circuit.The use of microcontroller PWM simplifies frequency square wave generator,frequency shifting and phase shift circuit,and control the frequency drift.(4)Due to the increase in the temperature of the motor operation caused by the drift of the work,the design of frequency tracking system to ensure the stable operation of the motor.Through the detection of piezoelectric ceramic signal feedback to the microcontroller,the microcontroller to determine the output PWM frequency.(5)Develop prototype to test the actual output performance.