Passive Probing Perception: Effect of Latency in Visual-Haptic Feedback

Latency is detrimental to haptic systems, specifically in networked telepresence systems. Although the latency effect on stiffness is well studied in the literature, it is not very clear if the latency effects on the stiffness perception are due to the displacement perception or the force perception. In this study, we propose passive probing which involves force perception alone, without any displacement of the finger, for studying latency effects. A psychophysical experiment is conducted with a set of artificially induced latencies which provides a quantitative measure of the effect of these latencies on three parameters: Just Noticeable Difference (JND), the time taken to reach the reference forces and the maximum overshoot. The results showed that the latency has a significant effect on the user ability in task performance after 185.5 ms. From the observation, the latency effect on JND in passive probing is similar to that of the stiffness perception (active probing) task which shows that the effect is significantly higher on the force perception rather than on the displacement perception.