Investigation of three-mod operation futures of travelling wave ultrasonic motor

INVESTIGATION OF THREE-MOD OPERATION FUTURES OF TRAVELLING WAVE ULTRASONIC MOTOR(Ph.D. Thesis)Altan GENCERGAZİ UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYAugust 2011ABSTRACTTravelling wave ultrasonic motors are recently being used in industrial applications. The speed of the ultrasonic motor can be controlled by adjusting three quantities. These are magnitude and frequency of two-phase voltages and the phase angle between them. In this thesis, in order to investigate the speed response of a travelling wave ultrasonic motor under three-mode (three-quantity) operation, a micro controller based digitally controlled speed driver system was designed and implemented. While the driver system has a simple construction and small size it provides access to enter speed and direction commands digitally as well as tracking the real motor speed, voltage and current on an LCD. The system was tested in a laboratory for different speed and load cases under three-mode operation. In the test, driving frequency and magnitude of phase voltages and phase shift between two phases have been used as the control inputs. The results obtained from simulation and experiments were analyzed and presented with comparisons. It was seen that the speed of the ultrasonic motor can be controlled more widely with the frequency, the amplitude of the phase voltages has less effect on the speed interval and the phase shifting has very small effect on the speed interval. When the frequency and amplitude adjustments reach the lower limitations for the lowest speed the phase angle still offers a way to control the speed.