Neuro-fuzzy dual-mode control of travelling-wave ultrasonic motors

With their significant advantages over traditional electromagnetic motors, ultrasonic motors (USMs) are becoming attractive. This paper presents a neuro-fuzzy dual-mode controller, combining the knowledge-based fuzzy logic and the learning-incorporated neural network as well as using dual control inputs, for servo control of travelling-wave USMs. According to the proposed neuro-fuzzy control, both the driving frequency and phase difference of the USM system are simultaneously adjusted on-line. Experimental results have verified its superior steady-state and dynamic performances under various reference inputs.