Causal modeling and identification of a travelling wave ultrasonic motor

This paper deals with the causal modeling of a Traveling Wave Ultrasonic Motor; the aim of the study is to build an approach which may take into account the physical contact responsible for the pull-out phenomenon, but straightforward enough to be useful for control. As the parameters available for the modeling can not be obtained following the well known electromechanical equivalent scheme identification, a new identification method is proposed. In this purpose, the model of the motor is expressed in the traveling wave rotating frame