Modulation of Curvature of Soft Ball by Facing Motion

Abstract

Two fingers coming into contact with each other at the same speed sometimes produces the sensation of contact with a flat rigid surface. This illusory sensation is considered to be caused by skin deformation and kinesthesia similar to those that would be produced by contact with a hard surface. We speculated that it would be possible to produce the same tactile sensation as that of contact with a flat rigid plate by placing a soft sphere with the same curvature and hardness as a finger against a finger and moving it at a speed equal to that of the finger. We conducted an experiment to verify the modulation effect of perceived curvature by comparison with various curvature samples. In addition, we developed a prototype of an encountered-type haptic display using this illusion and verified the applicability of the illusion.