Speed control of ultrasonic motors using neural network

Ultrasonic motor (USM) is a newly developed motor and it has an excellent performance and many useful features, so it has been expected to be of practical use. However, this motor has a heavy nonlinearity which varies with driving conditions. Therefore, precise speed control of ultrasonic motor is difficult. This paper proposes a new speed control scheme for ultrasonic motor using a neural network. The proposed controller can approximate the nonlinear input-output mappings of the motor using the neural network, and can compensate the characteristic variations by online learning. The usefulness and validity of the proposed control scheme is examined by experiments.