Parameter identification of ultrasonic motors

Advanced control strategies for piezo drives require suitable parameter identification methods similar to conventional electrical motors. In this paper a parameter identification method for traveling wave type ultrasonic motors is presented based on investigations in the frequency domain. First, a model refinement with respect to the piezoceramic energy conversion process is adopted, which differs from conventional models of ultrasonic motors. Next, a parameter identification method is derived using the novel model approach which is then verified by simulations. The need for performing parameter identification in the practical operation range is discussed by simulation results. Finally, the parameter identification method is applied to measured values and the results are discussed also with respect to the distribution of energy losses within the motor.