Neural-network controller for parallel-resonant ultrasonic motor drive

A newly designed driving circuit for the traveling-wave type ultrasonic mot or (USM). Which is composed of a push-pull de-dr power converter using PWM direct duty-cycle control and a current-source two-phase parallel-resonant capacitor-parallel load inverter, is described in this study. Moreover, sin ce the dynamic characteristics of the USM are difficult to obtain and the m otor parameters are time varying, an on-line trained neural-network (NN) co ntroller is proposed to control the rotor speed and position of the USM. Ac curate tracking response can be obtained due to the powerful on-line learni ng capability of the NN controller, Furthermore, the influence of parameter variations and external disturbances on the USM drive also can be reduced effectively. The effectiveness of the NN controlled USM drive system is dem onstrated by experimental results.