A novel high thrust-weight ratio linear ultrasonic motor driven by single-phase signal

This paper presents an ultrasonic motor with a high thrust-weight ratio. The miniaturized motor is 13 mm × 5 mm × 3.8 mm in size and uses the first-order bending vibration mode (B1 mode) and second-order bending vibration mode (B2 mode) to realize bidirectional movement through a single-phase driving signal. The theoretical trajectory and output thrust of the motor driving foot are initially studied. Subsequently, a finite-element model of the motor is established, and its dynamic performance is studied. Next, the prototype of the motor is fabricated and tested. The results show that errors in the B1 and B2 modes are 1.976% and 0.436%, respectively. Finally, an experimental setup is constructed to test the mechanical properties of the motor. The maximum output velocities of the motor is approximately 158 mm/s at 58.917 kHz in the B1 mode and approximately 137 mm/s at 113.581 kHz in the B2 mode. The maximum thrust force values of the motor in the B1 and B2 modes are approximately 1.32 N and 1.08 N, respectively, with 7 N preload and 120 V_pp voltage. The overall mass of the motor stator is 1.0 g, so the motor thrust-weight ratio reaches 134.69.