A Device and Method for Multimodal Haptic Rendering of Volumetric Stiffness

Vibrotactile signals are produced during haptic exploration of compressible objects through a variety of contact and bulk mechanical processes. Prior studies have found that vibrotactile feedback can influence stiffness perception, but the reason for this is unknown. Here, we investigated the role of vibration in stiffness perception during object squeezing. We propose a physically motivated explanatory model and rendering algorithm relating vibrotactile and force-displacement cues, then present a novel haptic interface that was designed to accurately reproduce these cues. Finally, we present the results of an experiment on the perceptual integration of vibrotactile and force-displacement cues during oneand two-finger stiffness perception. The results indicate that vibration feedback can increase perceived object softness during interaction with one finger, but preclude a similar conclusion for two-finger grasping. We argue that the results support the proposed model once innate differences in oneand two-finger exploration are accounted for.