Experimental study of haptic information pickup in manipulation

An ecological study of haptic perception and action in tool use has been proposed. The result of such a study would be a theory of tool use to guide haptic interface, telemanipulator, and virtual environment design. As a first step in this study, we conducted an experimental study of haptic information pickup in a single degree-of-freedom positioning task. The task consisted of moving the handle of a one degree-of-freedom manipulandum to a target location using haptic perception. The manipulandum was controlled to exhibit impedances characterizing viscous drag, or damping. Damping in the target region was made to be different from the damping in the surrounding environment (ambient damping). Subjects were instructed to move to, and stop in, the target zone as rapidly as possible. The results of the experiments show that with our apparatus subjects could detect targets designated by differences in target and ambient damping greater than 2.27 N·s/m. For very large differences in target and ambient damping, subjects performed almost as well using haptic perception alone as they did when they could also see the target.