Tactile display using elastic waves

As a basis for a tactile display, it is important to understand the mechanism of tactile sensation, so we analyze the elastic waves inside a finger in tactile exploration with a two-layered, half-infinite elastic finger model, and derive a mapping from the shapes of objects to the displacements of the mechanoreceptors. It is shown that the mapping from displacements of the finger surface to displacements of the mechanoreceptors is a one-to-one mapping. Therefore, it is necessary to create the same displacements of the finger surface as in actual exploration for tactile virtual reality (VR). However, the mapping from shapes of objects to displacements of the finger surface is shown to be a many-to-one mapping because of the mechanical properties of skin. So, we use the envelope of the amplitude-modulated Lamb wave on an elastic plate as an alternative shape to the real object, because its shape can be easily controlled. The generation of the wave is confirmed with an experimental device of silicon rubber vibrated by voice coils.