Tilting ultrasonic motor using extension and shear vibration modes

We propose a miniature tilting ultrasonic motor which can change its end effector's angle by combining extension and shear vibration modes generated in the stator. The tilting motor is useful for enlarging the range of view of cameras and mirrors for various applications, such as those at the end of medical endoscopes. In this study, we design astator by piezoelectric analysis based on the finite element method and evaluate the performance of the prototype motor through experiments. The stator with piezoelectric elements is a rectangular block with a height, width, and length of 10.5, 13.0, and 14.0 mm respectively, and has a semi-circular groove with a diameter of 10 mm. Two semi-cylindrical sliders placed in the groove move in forward and backward directions; the linear motions of the two sliders are converted to the tilting motion of the end effector comprising two linkages connected to the sliders. The thrust force of the motor is improved by optimizing the preload between the stator and sliders. The primary performance measures, such as its thrust force and linear velocity, are experimentally evaluated. The resultant tilting ultrasonic motor demonstrates its tilting motion along the desired trajectory.