Playmate robots that can act according to a child's mental state

We propose a playmate robot system that can play with a child. Unlike many therapeutic service robots, our proposed playmate system is implemented as a functionality of the domestic service robot with a high degree of freedom. This implies that the robot can play high-level games with children, i.e., beyond therapeutic play, using its physical features. The proposed system currently consists of ten play modules, including a chatbot with eye contact, card playing, and drawing. The algorithms of these modules are briefly discussed in this paper. To sustain the player's interest in the system, we also propose an action-selection strategy based on a transition model of the child's mental state. The robot can estimate the child's state and select an appropriate action in the course of play. A portion of the proposed algorithms was implemented on a real robot platform, and experiments were carried out to design and evaluate the proposed system.