A cylindrical traveling wave ultrasonic motor using bonded-type composite beam

A cylindrical traveling wave ultrasonic motor using bonded-type composite beam is proposed in this work. In this new design, a new exciting mode for L-B (longitudinal-bending) hybrid vibrations using bonded-type is adopted, which requires only two pieces of PZT ceramic plates and a single metal beam. In the new motor, the traveling wave of a cylinder can be excited by the L-B vibrations of a bonded-type beam. When two alternating voltages with phase difference are applied, the longitudinal and bending vibrations of the beam can be generated synchronously based on the new exciting mode for L-B hybrid vibrations, and the temporal phase difference of the two vibrations is always 90°. Finite element method is adopted to realize the modal degeneration in order to confirm the final structural parameters of the motor, and analyze the motion trajectory of the driving tip. After the fabrication of a prototype, the vibration characteristics and mechanical output ability are measured. The maximum no-load speed and maximum output torque of the prototype are 342 rpm and 6.26 mN m at a voltage of 100 V_rms.