Abstract: According to design problem of friction material stuck onto the stator surface, the rotor is assumed to be rigid body and the frictional material on stator surface to be visco-elastic material, a new visco-elastic contact model of traveling wave ultrasonic motor (TWUSM) is presented. In modeling, the influence of the inertia of frictional layer is considered, then two parameters, tangential and normal equivalent mass of the stator contact layer, are introduced, and the initial border term is revised. Newton’s dynamics law is applied to build an interface drive model. By means of this model, not only the normal pressure and the tangential speed distribution of the contact zone, load characteristics and transmission efficiency of TWUSM can be simulated and analyzed, but also the effects of interface parameters between stator and rotor on output characteristic of TWUSM can be calculated numerically. Based on this contact model, load characteristic of TWUSM is simulated numerically by using MATLAB method, and the simulated result is compared with test result. It is shown that their load characteristics have good agreement, and then the rationality of driving model is testified.

Key words: Contact model, Friction material, Ultrasonic motor