A Fingertip Haptic Display for Improving Curvature Discrimination

This paper presents a novel haptic device providing both kinesthetic and cutaneous cues informative of shape geometry at the contact point. The system is composed of a supporting kinesthetic haptic interface and an innovative fingertip haptic display that can instantaneously orient a small plate along the tangent plane at the contact point with a virtual shape and bring it in contact with the fingertip. We show how this local augmentation of displayed haptic information can improve human performance in shape exploration, by assessing perception thresholds in curvature discrimination. When kinesthetic feedback was enriched with cutaneous cues, we found a significantly lower threshold for curvature discrimination (1.51 +/- 0.2 m(-1) vs. 2.62 +/- 0.61 m(-1), p < .05) for stimuli constituted of spheres with curvature ranging in the interval from 4-6 m(-1). This confirms the importance in haptic perception of the stimulation of cutaneous mechanoreceptors at the fingertip.