Motion error correction for non-contact ultrasonic motor driven by multi-layered piezoelectric actuators

Abstract

An active non-contact ultrasonic motor with the micro positioning abilities of a rotor was proposed and performances were tested. The stator had a simple cylindrical form, which enabled low manufacturing costs. A resonant frequency of 22.2 kHz at eighth flexural mode of vibration was observed. With appropriate assembly and operation of piezoelectric actuators, the flexure vibration of the stator travels in the circumferential direction. The component of the stator deformation in radial direction creates an air film pressure higher than ambient thereby suspending the rotor. Simultaneously, the component that propagates in the circumferential direction rotates the rotor based on acoustic viscous flow. It was experimentally confirmed by electrical conduction test that the rotor rotated with levitation from stator. In addition, piezoelectric actuators around the stator exciting the deflective vibration could make contact-free micro positioning abilities of the rotor with a minimum step width of 0.15 lm.

Frequency characteristics of non-contact ultrasonic motor with motion error correction

“…A prototype of a non-contact ultrasonic motor has been constructed to clarify basic performance [8]. In this paper, we describe an active non-contact ultrasonic motor that positions the rotor precisely without contact.…”

Speed control of an electromechanical integrated harmonic piezodrive system

“…A small sized non-contact ultrasonic motor was proposed in which the radiation pressure of the sound wave is used to transmit torque (Hirose, 1993). Based on it, a number of the non-contact ultrasonic motors were proposed and investigated (Isobe, 2005and Stepanenko, 2012. Besides it, a rolling-contacting ultrasonic motor was proposed in which the rollers are located between the grooves of stator, and the rollers drive the rotor to rotate (Hojiat, 2010).…”

Dynamics for an electromechanical integrated harmonic piezodrive system

“…Isobe proposed an active non-contact ultrasonic motor with the micro positioning abilities of a rotor in which contact-free micro positioning abilities of the rotor with a minimum step width of 0.15 μm were achieved [12]. Yang investigated a micro non-contact ultrasonic motor based on B22 vibration mode in which the rotor speed of 3569 rpm was given at the input voltage of 20 V and the driving frequency of 45.6 kHz [13]. Isobe constructed a PI controller to correct the detected motion error of the rotor in a non-contact ultrasonic motor [14].…”