Visuo-motor tracking with coordinated wrist movements under different combinations of visual and kinesthetic disturbances

This study addresses a major problem in the design of HCI (human-computer interface) systems: how to avoid or reduce the long learning/adaptation process and the corresponding attentional load of the underlying hand-eye coordination task that frequently affects HCI systems. In particular, we considered a 2D tracking task with two degrees of freedom of the wrist to a visual target whose frame of reference was rotated with respect to a body-fixed frame in a time varying manner. We investigated it by means of a wrist robot coupled with a virtual reality system. The experimental protocol consisted of applying kinesthetic and visual disturbances in a unimodal or bimodal manner and observing the tracking performance. The kinesthetic disturbance was provided by passively rotating the forearm of the subjects by the third degree of freedom of the wrist robot, while the visual disturbance was provided by rotating the visual scene. The results suggest that the combination of a suitable proprioceptive feedback with the kinematic redundancy of the HCI system might be a rather general principle for improving the efficiency of HCI systems.