Perception of a Mobile Service Robot's Proxemic Behavior and Appearance in Virtual Reality

Various robot-related, environmental and human factors influence the proxemics and the quality and perception of human-robot interactions (HRIs). This paper focuses on a selection of the most relevant robot-related factors: size, speed, and the robot's edge shape, which were systematically varied in two consecutive experiments. This gives important implications for human-centered robot behavior design, where non-verbal, proxemic behavior plays an important role. Therefore, in this study series, additionally to the indicated comfortable distance, the subjective discomfort elicited in a human when encountering a mobile service robot was investigated using a virtual reality (VR) setup. The results of the two conducted experiments show strong and consistent influences of size and speed both on the distance and discomfort. Besides, a small influence of the edge roundness of the robot on discomfort was found. Additionally, the results give implications at which distance a delivery robot should adapt its behavior depending on its design configuration in order to achieve as less discomfort in humans as possible.