A newly proposed T-shape piezoelectric actuator, composed of piezoelectric benders, was designed and studied. This actuator has four legs, and can walk in both forward and backward directions. The piezoelectric actuator has a simple structure and can be easily fabricated. It consists of a piezoelectric bender and a joint. The piezoelectric bender is composed of carbon and ceramic materials. Therefore, there is an advantage in that it can be fabricated on a very small scale. Elliptical displacements of the piezoelectric actuators were analyzed by finite element analysis. Elliptical motion at the tip occurred at two voltages having a 90-degree phase difference. Based on the finite element analysis results, prototype actuators with maximum displacements were fabricated, and the characteristics of their movements were characterized.

A novel design of a simple square-frame USM (ultrasonic motor) was proposed. The stator of the motor consists of a square-frame shape elastic body and four rectangular plate ceramics. The four ceramics were attached to inner surfaces of the square frame elastic body. The same phase voltages were applied to the ceramics on horizontal surfaces, and 90 degree phase difference voltage were applied to the ceramics on vertical surfaces. To find a model that generates elliptical motion at outside of the stator, the finite element analysis program ATILA was used. The analyzed results were compared to the experimental results. As result, the model EL10EH3ET0.5CL4 which generates the maximum elliptical displacement was chosen by analyzing the resonance mode according to changes in frequency.