Finite Element Modeling of a Vibrating Touch Screen Actuated by Piezo Patches for Haptic Feedback

The aim of our work is to design a touch screen for displaying vibrotactile haptic feedback to the user via piezo patches attached to its surface. One of the challenges in the design is the selection of appropriate boundary conditions and the piezo configurations (location and orientation) on the screen for achieving optimum performance within the limits of human haptic perception. To investigate the trade-offs in our design, we developed a finite element model of the screen and four piezo actuators attached to its surface in ABAQUS. The model utilizes the well-known Hooke’s law between stress and strain extended by piezoelectric coupling. After selecting the appropriate boundary condition for the screen based on the range of vibration frequencies detectable by a human finger, the optimum configuration for the piezo patches is determined by maximizing the vibration amplitude of the screen for a unit micro Coulomb charge applied to each piezo patch. The results of our study suggest that the piezo patches should be placed close to the clamped sides of the screen where the boundary conditions are applied.