Computer Simulation and Modelling of 3D Travelling Wave Ultrasonic Motor Using a Flexural Vibration Ring Transducer

Abstract

This paper presents a 3D piezoelectric ultrasonic motor using a single Flexural Vibration Ring Transducer. The motor consists of three main parts, the rotor, the stator and the housing unit. The stator is a piezoelectric transducer ring made from PZT S42 material. Three steel rods and a magnet were designed to support the rotor. The rotor is a sphere of metal that rests on the stator intersecting at the tips of the steel rods and the magnet. The housing unit is made of Perspex, a transparent thermoplastic material. Longitudinal and bending vibration modes, of oscillating structures are superimposed in the motor, generating elliptical micro motions at the driving tips. Pressing the rotor against the stator tips the micro motions are converted into a 3D rotational motion, via the friction between the tips of the three rods and the rotor. The motor structures, working principles, design and finite element analysis are discussed in this paper. A prototype of the motor was fabricated and its characteristics measured. Experimental tests show typical speed of movement equal to 35 revolutions per minute, a resolution of less than 5μm and maximum load of 3.5 Newton.