A linear ultrasonic traveling wave motor of the ring type

This paper gives results on theoretical and experimental investigations concerning a linear traveling wave motor. The stator of the motor consists of straight and curved beams. A detailed finite-element analysis shows that double eigenfrequencies exist for certain ratios of length-to-radius. The excitation of the corresponding mode shapes with a temporal phase shift of leads to traveling bending waves. Due to the coupling between transverse and longitudinal motions of such a system, the axial velocities of the beam's surface points vary along the beam. An experimental prototype motor behaved according to the theoretical predictions about the dynamics of the stator.