Comparison of Augmented Reality Rearview and Radar Head-Up Displays for Increasing Spatial Awareness During Exoskeleton Operation

Full-body powered exoskeletons for industrial workers have the potential to reduce the incidence of work-related musculoskeletal disorders while increasing strength beyond human capabilities. However, operating current full-body powered exoskeletons imposes different loading, motion, and balance requirements on users compared to unaided task performance, potentially resulting in additional mental workload on the user which may reduce situation awareness (SA) and increase risk of collision with pedestrians, negating the health and safety benefits of exoskeletons. Exoskeletons could be equipped with visual aids to improve SA, like rearview cameras or radar displays. However, research on design and evaluation of such displays for exoskeleton users are absent in the literature.

This empirical study compared several augmented reality (AR) head-up displays (HUDs) in providing SA to minimize pedestrian collisions while completing common warehouse tasks. Specifically, the study consisted of an experimental factor of display abstraction including four levels, from low to high abstraction: rearview camera, overhead radar, ring radar, and no visual aid (as control). The second factor was elevation angle that was analyzed with the overhead and ring radar displays at 15°, 45°, and 90°. A 1x4 repeated measures ANOVA on all four display abstraction levels at 90° revealed that every display condition performed better than the no visual aid condition, the Bonferroni post-hoc test revealed that overhead and ring radars (medium and high abstraction respectively) received higher usability ratings than the rearview camera (low abstraction). A 2x3 repeated measures ANOVA on the two radar displays at all three display angles found that the overhead radar yielded better transport time and situation awareness ratings than the ring radar. Further, the two-way ANOVA found that 45° angles yielded the best transport collision times. Thus, AR displays presents promise in augment SA to minimize collision risk to collision and injury in warehouse settings.