COMPUTER SIMULATION AND MODELLING OF STANDING WAVE PIEZOELECTRIC ULTRASONIC MOTOR USING A SINGLE FLEXURAL VIBRATION RING TRANSDUCER

A rotary standing wave ultrasonic motor using single flexural ring transducer is developed and presented in this paper. The motor consists of three main components, the stator, rotor and housing unit. The stator is a piezoelectric transducer ring. The rotor is designed of a compact driving wheel and the shaft. The housing unit is made of a transparent thermoplastic Perspex material and is part of the motor working mechanism. The motor design, structure, working principles and modelling using finite element analysis is discussed and presented in this paper. The simulation and modelling using finite element analysis for the motor is used in the motor design development process. Finite element has been used to examine the motor structure by performing an algebraic solution of a set of equations, describing an ideal model structure, with a finite number of variables. The established simulation and modelling for ultrasonic motor using finite element analysis enabled to select the material of the flexural transducer ring, investigate the material deformation, defining the operating parameters for the motor and establish the principles of motion. The motor working principles is based on creating travelling waves vibration modes, of oscillating structures that are superimposed in the stator, generating elliptical micro motions at the stator tips. Pressing the rotor against the stator tips, using an elastic spring, the micro motions are converted into a rotary motion via the friction between the tips of the stator and the rotor. A prototype of the motor was fabricated and its characteristics measured. Experimental tests showed that the electrical working parameters are: Current: 100 m-amp's, Voltage: 100 volts, Frequency: 41.7kHz, typical speed of movement: 32 revolutions per minute, a resolution of less than 50gm and maximum load of 1.5 Newton.