Remote Friction Control on 3-dimensional Object Made of Polystyrene Foam Using Airborne Ultrasound Focus

In this study, we propose a method to remotely change the friction of a three-dimensional surface made of polystyrene foam. In a previous study, a system that projects an image onto a two-dimensional polystyrene foam surface and irradiates ultrasound according to a finger’s position in contact with the surface to change the friction has been proposed. In this study, we extended it to a three-dimensional shape and quantitatively evaluated the change in friction. It was confirmed that the frictional change could be obtained even when extended to three dimensions but that the frictional change was less likely to occur depending on how the polystyrene foam was fabricated. This technology can be applied for adding the tactile feel to a simple 3D mockup model made of polystyrene foam.