Basic experiments on collision of sharp mechanical hazards against eye for estimation of injury severity

This study deals with the avoidance/mitigation possibilities in an estimation of severity of injury from a mechanical hazard when a sharp-edged object approaches a human eye. We assume that the sharp end effector of a robot approaches the eye of a human in a human-robot coexistence system. We conduct a static eye collision experiment and dynamic eye collision experiment taking into consideration human avoidance/mitigation actions. Three conditions (collision position, collision angle, and eyelid state - open/closed) are varied in the static collision experiment. Consequently, it is confirmed that differences in severity result from these changes in the experimental conditions. In the dynamic collision experiment, Bell´s phenomenon, which is an upward rotation of the eyeball at the time of closing the eyelid, is taken into consideration, and two conditions (collision position and angle) are changed. Through these experiments, we find that Bell´s phenomenon plays an important role in the risk estimation. Although the avoidance/mitigation possibilities have not previously been taken into consideration in eye collision experiments, we consider these to be indispensable to the risk estimation.