Time delay in haptic telepresence arising from compression or communication alters the phase characteristics of the environment impedance. This paper describes how well a human operator can discriminate these changes in haptic environments. Three different environments are rendered on a haptic interface and manually excited by a human operator using sinusoidal movements. We find that time delay in haptic feedback can be discriminated starting from 15 ms in a pure damper environment, 36 ms in a spring system, and 72 ms when moving a damped inertia. We conclude that the discrimination thresholds increase with the absolute phase between velocity and force signals resulting from the remote environment characteristics. These results may benefit the human-centered design of high-fidelity haptic communication protocols and haptic filters. Key words: Time delay, telepresence, psychophysics.
Markus Rank, Zhuanghua Shi, Hermann J. Müller