Double-Sided Tactile Interactions for Grasping in Virtual Reality

For grasping, tactile stimuli to multiple fingertips are crucial for realistic shape rendering and precise manipulation. Pinching is particularly important in virtual reality since it is frequently used to grasp virtual objects. However, the interaction space of tactile feedback around pinching is underexplored due to a lack of means to provide co-located but different stimulation to finger pads. We propose a double-sided electrotactile device with a thin and flexible form factor to fit within pinched fingerpads, comprising two overlapping 3 × 3 electrode arrays. Using this new tactile interface, we define a new concept of double-sided tactile interactions with three feedback modes: (1) single-sided stimulation, (2) simultaneous double-sided stimulation, and (3) spatiotemporal double-sided stimulation. Through two user studies, we (1) demonstrate that participants can accurately discriminate between single-sided and double-sided stimulation and find a qualitative difference in tactile sensation; and (2) confirm the occurrence of apparent tactile motion between fingers and present optimal parameters for continuous or discrete movements. Based on these findings, we demonstrate five VR applications to exemplify how double-sided tactile interactions can produce spatiotemporal movement of a virtual object between fingers and enrich touch feedback for UI operation.