Experimental study of noncontact ultrasonic motor with non-symmetrical electrode

We have proposed a novel noncontact ultrasonic motor based onnon-symmetrical electrode driving. The configuration of thiselectrode and the fabrication process of rotors are presented. Its vibrationcharacteristics are computed and analysed by using the finite elementmethod and studiedexperimentally. Good agreement between them is obtained. Moreover,it is also shown that this noncontact ultrasonic motor is operated inantisymmetric radial vibration mode of $B_{21}$ mode. The maximum revolutionspeed for three-blade and six-blade rotors are 5100 and 3700,r/min at aninput voltage of 20V, respectively. Also, the noncontact high-speedrevolution of the rotors can be realized by the parts of I, III of theelectrode orII, IV of the electrode. The levitation distance between the stator androtor isabout 140$mu $m according to the theoretical calculation and the experimentalmeasurement.