P5G-6 A Multi-DOF Ultrasonic Motor Using In-Plane Deformation of PZT Elements

A new multi degree-of-freedom (multi-DOF) ultrasonic motor using in-plane deformation of PZT elements is proposed in this paper. The stator of the motor consists of a hollow metal cylinder, whose outside surfaces are flattened on four sides at 90 degrees to each other. Four rectangular PZT plates polarized in thickness direction are bonded on them. By using the deformation of PZT plates in the plane perpendicular to the direction of polarization, the rotation around z-axis is generated by combining both bending vibration modes; whereas the rotation around x- or y-axis is generated by combining the longitudinal vibration mode and one of the above bending vibration modes. The stator geometry is designed in detail using the finite element method, and a prototype of the multi-DOF ultrasonic motor is produced. Admittance of the stator and load characteristics of the motor has been measured, respectively. The results confirm that the motor successfully provides the desired multi-DOF motion around orthogonal axes with a single stator using in-plane deformation of PZT elements.