Experimental Study on Operator's Psychological Safety Field Model Considering Cobot Motion

Abstract

The motion mode of collaborative robots(cobots) is essential for ensuring workers' efficiency, improving trust in cobots, and reducing psychological stress. Since the existing researches do not form mathematical models for the relevant laws, it increases workers' psychological stress caused by the traditional cobot motion, which cannot realize safe, efficient, and natural human-robot collaboration(HRC). Based on existing research, the subjects' skin conductivity response(SRC) was collected using Electrodermal activity(EDA) equipment, and the laws of psychological stress generated when the robot approached the subjects at different speeds, minimum distances, and directions were investigated. It was found that the human body produced gradually increasing EDA signals as the speed increased and the distance decreased, while there was no significant change in EDA signals with the change of approach direction when the subject could observe the cobot motion. The empirical equation for the psychological stress of cobot motion on the subject was obtained by curve fitting the mean values of the EDA signals of the speed and minimum distance single-factor tests, and the operator psychological safety field model was established accordingly. The proposed model can provide theoretical support for cobots' safe, efficient, and natural motion planning.