Abstract: Based on the application of the energy principle and the special structure of the traveling-wave type ultrasonic motor, by using the analysis about those concepts, such as force of the stator ring’s surface, wave’s speed of the stator ring, the mechanical consumption of the stator ring, the force impress of the stator ring to the rotor ring standing in the mechanical features of the traveling-wave type ultrasonic motor, the power consumption and the torque equation of the rotor ring are analyzed in two different situations, use two different rotor material to establish the torque equation of traveling-wave type ultrasonic and provide practical mathematics model to develop the control theory of traveling-wave type ultrasonic motor.

Key words: Mathematical model, Movement of the rotor, Movement of the stator, Ultrasonic motor