Research On An Rotary Inertial Piezoelectric Motor

An inertial piezoelectric rotary motor is a new type of micro & special motor, drivenby asymmetric waveform voltage. It is different from traditional motor, and has theadvantages of simple mechanism, magnetic interference, fast response speed, positioningaccuracy et al. it has wide application prospects in the biological, electronics, medicalequipment, precision processing and precision operation fields and so on. However, theexisting inertial piezoelectric motor can not achieve the whole week continuous rotation,so this paper puts forward a new type of rotary inertia piezoelectric motor. It not only canachieve the whole week of continuous rotation, and has the advantages of simplestructure, easy miniaturization.This paper analyzes the rotary inertial piezoelectric motor driving principle.According to the principle of continuous body vibration, the dynamic model of simplifiedvibration structure has been built, and using the method of coupling beam and ring, thedynamic model has been built. Utilizing the two dynamic models, the natural frequenciesand modal functions of the vibrator bending in-plane vibration have been solved. Theinfluence laws of the two algorithms with changing the vibration structure parametershave been analyzed. Through compared and found the similar mode of two algorithms,the error of similar mode solved by two algorithms have been caculated. The results showthat: simplify the method can be used in the ring thickness is relatively thin and ringmodal stiffness of the beam smaller.According to the capacitance charge and discharge principle, the voltage responseequation of the ends of piezoelectric element has been deduced. The influence law ofcharge and discharge time of piezoelectric element on driving cycle is discussed.Utilizing piezoelectric equation and Lagrange equation, the generalized displacementequation of force vibration of the vibrator have been deduced. And according to elasticvibration superposition principle, the response equation of displacement, velocity andacceleration have been gained. The influence law of changing system parameters andstructure parameters of the vibrator on displacement, velocity and acceleration response of vibrator-beam has been analyzed. Utilizing Fourier transform, the excitation signal hasbeen changed from the time domain into frequency domain. The equation of inertialimpact moment of vibrator has been deduced. In the frequency domain, the influence lawof changing system parameters and structure parameters of the vibrator on inertial impactmoment of mutations moment and inertial impact moment difference of two mutationsmoments have been analyzed. The results show: When frequencies value of excitationsignal is betweenωj/2 toωj, the inertial impact moment maximum difference of twomutations moments appears.The rotary inertial piezoelectric motor prototype has been designed and developed.Utilizing the test system, when the excitation signal frequency is 6.310kHz and drivingvoltage peak 100V, the maximum speed of prototype is 59.6r/min, maximum torque is0.35Nmm. And the speed (torque) is increased along with the excitation signal peakvoltage increases. The control methods of prototype, adjusting voltage and frequencieshave been put forward. The test results verify the accuracy of the theoretical analysis.