Neural-network controller for parallel-resonant ultrasonic motor drive

A newly designed driving circuit for the traveling-wave type ultrasonic motor (USM), which is composed of a push-pull DC-DC 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, since the dynamic characteristics of the USM are difficult to obtain and the motor parameters are time varying, an online trained neural-network (NN) controller is proposed to control the rotor speed and position of the USM. Accurate tracking response can be obtained due to the powerful online learning 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 demonstrated by experimental results.