A novel hybrid mode linear ultrasonic motor with double driving feet

A novel standing wave linear ultrasonic motor with double driving feet based on longitudinal-bending coupling mode is designed in this study. The motor adopts the bonded-type structure, and four pieces of piezoelectric ceramics on a metal beam are divided into two groups. Two voltages with 90° phase difference are applied to two groups of Pb-based lanthanumdoped zirconate titanates ceramics, respectively. Then the first longitudinal and second bending modes generated are superimposed on the stator, which can produce elliptical motion trajectories on the driving feet. The excitation method and driving mechanism of the motor are illustrated in detail. A finite model of the stator is established in the ANSYS parametric design language interface, and the operating mode of the stator and motion trajectories on the driving feet are discussed. The prototype is fabricated, and its impedance characteristics and mechanical output performance are tested. The results show that the maximal no-load velocity of the motor is ∼147.78 mm/s under a voltage of 200 V and a preload of 3 N. The maximum thrust force is ∼1.1 N when the voltage and preload are 200 V and 6 N, respectively.