An in-plane traveling wave ultrasonic motor based on longitudinal vibration and bending vibration

A novel micro ultrasonic motor for multi-channel actuator control is proposed. It is composed of a stator constituted with a ring and two rod-shaped transducers and two cone shaped rotors. Two rod-shaped transducers have rectangular cross section, where four sets of piezoelectric element are bolted. Two sets excite longitudinal vibrations of the bars, and the other sets excite flexural vibrations of the bars. FEM (finite element method) simulation shows that symmetric bending vibrations and anti-symmetric longitudinal vibrations of the two rod-shaped transducers impel a plane traveling wave in the surface of the ring. The prototype of the motor was made and investigated experimentally for its performance. Its maximum unloaded speed of the motor is 182r/min and the maximum output torque is 0.2N·m. Its body is long and narrow which is suitable for the installation of the multi-channel actuator control.