Towards Localized Tactile Feedback on Touch Surfaces: Finite Element Analysis of a Vibrating Touch Screen Actuated by Piezo Patches

Surface haptics technologies offer an augmented user experience by providing a unique and distinctive interaction between the finger and touchscreen. In this study, we focus on a touch screen design to display vibrotactile tactile feedback to the user through piezo patches located on its surface. We investigated the effects of boundary conditions, piezo configurations, and materials of the touch surface and piezo patches that will achieve the highest deformation on the touch surface, considering the most sensible human tactile perception frequency using the ANSYS FEM software package. In our analysis, we used three different touch surface and piezo patch materials, three different boundary conditions, four different piezo patch locations, and three different touch surface thicknesses. The results showed that the boundary conditions and thickness of the glass have a significant effect on the first natural frequency of the touch surface, and the results leading to best human tactile perception were obtained by fixing four piezo patches at four sides of the touch surface. Based on the determined configuration in the modal analyses, we performed a response surface optimization study to estimate the geometry of the touch surface (width, height, thickness), which will result in maximum deformation on the touch surface. We achieved the best configuration (max total deformation at about 250 Hz first modal frequency) with 160 × 90 × 0.28 mm and 190 × 110 × 0.4 mm dimensions. In the future, we will develop models to render localized tactile feedback on a touchscreen-based on piezo patches operating at various combinations (i.e., sequence, amplitude, frequency), which will be predicted based on the FEM simulations.