Framework for a Two-step Evaluation of Haptic Displays

Haptic displays can greatly facilitate manual control tasks. Their capacity of allowing the operator to perceive the desired dynamics is an important design parameter. However, attempts to evaluate haptic displays on the basis of what dynamics humans actually perceive are scarce. This paper proposes a two-step framework which incorporates the characteristics of human haptic perception into the evaluation of haptic displays. The first step is to evaluate the haptic display based on a recently developed model of the threshold for changes in the perception of system dynamics. It allows us to know the frequency spectrum in which a haptic device alters the operator's perception of the system dynamics. The second step is then to understand how the perceived dynamic distortions affect the operator's characterization of the system dynamics. Findings from recent psychophysical studies allow us to relate the changes in perception caused by the haptic device to changes in the perceived mechanical properties of the system. A numerical example illustrates how haptic displays can be evaluated using the proposed framework.