Structural Design And Dynamic Characteristics Study Of Electromagnetic Modulated Non-contact Rotating Piezoelectric Motor

The non-contact piezoelectric motor is a piezoelectric motor that does not contact the stator and the rotor.Based on the previous research,this paper proposes a new type of electromagnetic modulation non-contact piezoelectric motor prototype structure.It realizes the non-contact coupling of stator and rotor,and has the characteristics of reliable structure,stable operation,convenient control and less susceptible to external environment.The improved motor still uses the piezoelectric stack as the driving component,the external driving force and driving displacement are obtained by the piezoelectric stack reverse piezoelectric effect,and the driving line displacement is converted into rotation by the designed bistable flexible hinge micro-displacement amplifying mechanism.The angular displacement is modulated by the electromagnetic modulation mechanism to modulate the reciprocating swing angle into a unidirectional continuous rotation of the rotor,realizing the operation of the electromagnetically modulated non-contact piezoelectric motor.In this paper,the piezoelectric-electromagnetic electromechanical coupled electromagnetic moment equation is established,and the amplification factor of the bistable flexible hinge micro-displacement amplifying mechanism and the influence of parameters on the variation of the amplification factor are obtained.The results show that the piezoelectric-electromagnetic electromechanical coupling electromagnetic moment is most affected by the peak value of the modulation voltage,the air gap and the number of turns;the amplification factor is most affected by the length of the AB beam and the BC beam.The free vibration equation of the piezoelectric motor drive system is established,and the first 5 natural frequencies and modal functions of the components of the drive system under no-load and full load are solved.The influence of main parameters on the natural vibration modes of the free vibration of the drive system is analyzed and compared.The results show that the main parameters of the bistable flexible hinge micro-displacement amplifying mechanism in the drive system have significant influence on the vibration modes of the components of the drive system;the no-load and full-load states have different natural frequencies.The forced vibration equation of the drive system under the vibration of the piezoelectric stack is established.The forced vibration displacement response and velocity response of the components of the drive system and the amplitude-frequency phase of the system are solved respectively under the square wave excitation away from the first-order natural frequency.and the amplitude-frequency characteristics of the system are solved,The influence of the main parameters on the forced displacement response and amplitude-frequency characteristics of each component is analyzed.The results show that the displacement of the end of the AB beam,the end of the BC beam and the DE end of the intermediate axis are the largest,Therefore,it is more beneficial to the displacement amplification of the mechanism below the first order natural frequency excitationThe experimental prototype was assembled and a motor performance test system has built.Tested the output characteristics of the bistable flexible hinge micro-displacement amplifying mechanism;Using the sweep frequency test to obtain the first-order free vibration natural frequency of the drive system.The vibration amplitude is measured point by point,and the first-order mode is drawn and compared with the theoretical calculation results.Finally,the rotational speed,step angle and torque of the output characteristics of the experimental prototype are tested,and the influence curves of voltage peak,duty cycle and signal frequency on the output characteristics of the motor are plotted to verify the correctness of the research.