Toward active boundary conditions for variable friction touchscreens

Abstract

Variable friction touchscreens rely on ultrasonic plate vibrations to generate tactile effects on the surface. We propose using active boundary conditions (dynamically changing plate boundary conditions) for generating haptic perceptions from variable friction touchscreens. This method has several advantages over current designs including enabling greater control over the plate’s mode shape and the potential to generate new tactile effects on the plate surface. To explore the feasibility of this novel technique, we developed a plate model in ANSYS and conducted a series of simulations investigating three boundary condition parameters: location of the constraint, length of the constraint, and the “stiffness” of the constraint. We conclude that a variable stiffness boundary condition offers great potential for enabling systematic control of mode shapes and opens up possibilities of generating new tactile effects from these surfaces.