Determination of a safe slow robot motion speed based on the effect of environmental factors

The goal of this research was to determine a safe slow robot motion speed to be used for intervention tasks conducted in proximity to an industrial robot (e.g., programming and maintenance) when environmental factors were considered. The relevant factors associated with a robot station were dictated by previous research (Beauchamp and Stobbe, 1990). They were the illumination level, the luminance contrast between the robot and its background, the motion speed of the robot, and the field in which unexpected motions were initiated. The dependent variable measured was the distance the robot moved before the subject detected and responded to the unexpected robot motion. From the results, a multiple regression model was derived for predicting robot overrun distance. The model suggested that speeds in excess of 17 cm/s do not provide an adequate safety margin, and that 17 cm/s should be recommended as the maximum robot slow speed for work conducted in the vicinity of an industrial robot not equipped with dead-man switches.