Design of Piezoelectric Actuator for Braille Module by Finite Element Method.

Piezoelectric actuators, exhibiting large displacement and torque, are attractive for use in a broad range of actuator applications. One of the important applications is a tactile device, e.g., refreshable Braille display. Piezoelectric actuation in the Braille module requires large torque and large displacement for the tactile sensing of the human finger. In this study, we design piezoelectric actuators for the tactile interface including a Braille cell by finite element method (FEM) simulations. FEM simulations allow us to capture the entire device physics and solve the coupled piezoelectricity/solid mechanics problem. We investigated the effect of the structure, geometric variation, and physical properties of the materials used on the displacement and torque force. The studied structure includes a trilayer bimorph consisting of piezoelectric and supporting layers, and a multilayer with multiple bimorphs. The simulation result provides a useful guide toward piezoelectric actuators of tactile function.