A Physophysical Experiment of the Perception of Slip Distance

In this paper we present a slip display aimed at rendering sensations associated with a wet or lubricated surface rather than the typical dry surface presented by most haptic slip displays. The device features a perforated rotating belt to generate slip sensations with air jet streams delivered through the perforation. The presence of an air stream at the surface interface is hypothesized to decrease the perceived surface friction, giving rise to the sensation of a wet surface. The slip display was mounted on a linear track so that movement along the track resulted in a proportional slip distance, characterized by the tracking ratio (TR), the ratio of the amount of slip distance to the amount of proprioceptive distance traveled by the hand. A psychophysical experiment was conducted to investigate the effect of varying TR in order to determine the tracking fidelity necessary for the fingertip slip display to guide optimization of the device design. The just noticeable difference (JND) of the TR was found to be 5.55 with a standard deviation of 1.37. Future work will focus on refining the psychophysical experiment and testing more textures.