The effects of factors on human performance in the event of an unexpected robot motion

This study evaluates factors that could effect human performance in the event of an unexpected robot motion. The results of the study demonstrated many things. First, robot speed and task had an important impact on robot overrun distance. A longer overrun distance was observed with both increasing robot speed or task complexity. Second, illumination affected subject's performance; a longer overrun distance was observed with a low illumination level (10 Lux). Overrun distance, however, remained unaffected with increasing illumination level above 100 Lux. Furthermore, unexpected robot motions initiated in the peripheral field resulted in a longer overrun distance than motions initiated in the central field. The analysis of the robot speed by illumination interaction suggested that a low illumination level may further increase overrun distance with increasing robot speed. The analysis also suggested that when increasing robot motion speed, the overrun distance increases with low background-to-robot-arm luminance contrast ratios.