Investigating Breathing Expression of a Stuffed-Toy Robot Based on Body-Emotion Model

In this research, we focus on physiological phenomena expression of robots, propose the Body-Emotion Model (BEM), which concerns the relationship between the internal states of robots and their involuntary physical reactions. We expect that the robot will be able to express the delicate nuances of its intention by controlling robots' emotions and feelings with each individual parameter based on BEM. We propose a stuffed-toy robot system, BREAR, which has a mechanical structure to express breathing, heartbeating, temperature, and bodily movement. The breathing mechanism commonly controls the abdominal motion, breathing motion, and air flows of breath. In this paper, we focus on robot's breathing, verify two subjective evaluations: 1) the user's sense that the robot was alive and 2) the perceived states of the robot based on its breathing speed. The results showed that our proposed method of breathing expression can show a state of living and that the breathing speed was interpreted as the robot's emotion of arousal.