Disc type piezoelectric motor with two coaxial rotors

Abstract

tA small disc type piezoelectric motor was developed that can be used for micro flying vehicles. Theoperating principle of the motor is based on radial-bending type hybrid vibrations. The stator of themotor is a bimorph disc with the special quadrilateral shaped waveguides in the inner circumference ofthe disc. Waveguides are aligned with the tangential direction of the contacting ring. Such configurationof the actuator allows transforming radial vibrations of the disc into rotational vibrations of the contactingring. Elliptical motion of the contact points is obtained by superposition of radial and bending vibrationmodes. The motor has two truncated cone-shaped rotors. Although the actuator is asymmetrical, twocoaxial shafts of the motor can be rotated in both directions depending on the phase of excitation signals.Moreover, the proposed piezoelectric motor allows controlling the rotation speed of the rotors in differentdirections depending on the amplitude of the applied voltage. Numerical and experimental investigationof the piezoelectric motor was performed to validate the operating principle and to analyze vibrationsof the contact points. Electrical and mechanical output characteristics of the piezoelectric motor weremeasured. The motor achieved a maximum no load rotational speed of 7108 rpm at 15 V while maximumtorque is 0.0647 mN m.