Study on avoidance action parameters against a sharp end-effector tip approaching human's eyes

In this study, a psychological experiment is conducted to investigate harm-avoidance action characteristics in humans in close contact with robotic devices. For the experiment, a situation is created in which the sharp end-effector tip of a robot suddenly approaches the eyes of a facing participant. We define three parameters that represent harm-avoidance action characteristics: the avoidance reaction time, maximum avoidance acceleration, and maximum avoidance speed. The results suggest that the avoidance reaction time depends on the initial distance between the human's eyes and the approaching object. The results show that there are individual differences in all parameters studied. The results also show that the avoidance reaction time is negatively correlated with the other two parameters, which have a strong positive correlation with each other. We conclude that the avoidance reaction time and maximum avoidance speed are considerable parameters on avoidance actions.