Longitudinal and bending hybrid linear ultrasonic motor using bending PZT elements

In this study, a new linear ultrasonic motor using bolt-clamped Langevin type transducer with two feet is proposed. In this new design, only the bending vibration ceramics are employed; the longitudinal and bending vibrations of the transducer are excited by adopting a new exciting mode. Two groups of ceramics on both sides of the neutral plane of the bending mode shape are excited by two alternating voltages with phase difference. Then, the vibrations are composed and generate elliptical trajectories at the driving feet. The resonance frequencies of the two vibration modes of the motor are tuned to realize the modal degeneration using finite element method. The prototype motor achieved a maximum speed of 560 mm/s and a maximum output force of 55 N at a voltage of 450 V_p-p.