A new way to understand mechanical characteristics of an ultrasonic motor by using a finite-element (FE) analysis is presented. First, the vibration mode of a stator by using a finite-element method (FEM) code is calculated. The path of the elliptic motion of the stator's teeth is obtained. The computed vibration mode at the surface of the stator is compared with the measured one by using an electrooptical displacement transducer. Next, the contact condition of the rotor/stator is calculated. The stick/slip behavior at the contact interface of the rotor/stator is taken into account. The displacement and velocity of the rotor/stator, the distribution of the stick/slip area, the rotational speed of the rotor, and the friction loss of the motor are obtained. The calculated rotor displacement and torque-rotational speed (T-N) curve correspond closely to the experimentally measured ones. Furthermore, an internal loss of the rotor/stator and the loss of the supporting felt is measured. The total loss of the motor obtained by adding the aforementioned losses and the calculated friction loss agree with the measured total loss. The calculated and the measured efficiency of the motor also agree.
|IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
|Published - 1992 11月
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