Perception of Mechanical Properties via Wrist Haptics: Effects of Feedback Congruence

TL;DR

This study shows that wrist haptic feedback can effectively convey mechanical properties of virtual objects, with perception improved when feedback mapping aligns with interaction forces, enhancing virtual interaction experiences.

Contribution

It demonstrates that congruent wrist haptic feedback improves perception of virtual object properties, highlighting the importance of feedback mapping in wrist-based haptics.

Findings

Perception accuracy increased with congruent feedback.

Discrimination performance was positively affected by feedback congruence.

Subjective reports favored congruent feedback conditions.

Abstract

Despite non-co-location, haptic stimulation at the wrist can potentially provide feedback regarding interactions at the fingertips without encumbering the user's hand. Here we investigate how two types of skin deformation at the wrist (normal and shear) relate to the perception of the mechanical properties of virtual objects. We hypothesized that a congruent mapping between force at the fingertips and deformation at the wrist would be better, i.e. mapping finger normal force to skin indentation at the wrist, and shear force to skin shear at the wrist, would result in better perception than other mappings that either mixed or merged the two direction into a single type of feedback. We performed an experiment where haptic devices at the wrist rendered either normal or shear feedback during manipulation of virtual objects with varying stiffness, mass, or friction properties. Perception of mechanical properties was more accurate with congruent skin stimulation than noncongruent. In addition, discrimination performance and subjective reports were positively influenced by congruence. This study demonstrates that users can perceive mechanical properties via haptic feedback provided at the wrist with a consistent mapping between haptic feedback and interaction forces at the fingertips, regardless of congruence.