Walking together

This paper presents a computational model for side-by-side walking within human-robot interaction (HRI). In this work we address the importance of future motion utility (motion anticipation) of two walking partners. Previous studies only considered a robot moving alongside a person without collisions and with simple velocity-based predictions. In contrast, our proposed model includes two major considerations. First, it considers the current goal, modeling side-by-side walking as a process of moving toward a goal while maintaining a relative position with the partner. Second, it takes the partner's utility into consideration; it models side-by-side walking as a phenomenon where two agents maximize mutual utilities rather than only considering a single agent utility. The model is constructed based in a set of trajectories from pairs of people recorded in side-by-side walking; then, parameters of the model were calibrated for a mobile robot and tested in an autonomous robot walking side-by-side with participants. Finally, two evaluations were performed. The first evaluation shows that the proposed model considering mutual utilities performs better than a single utility method and a method that keeps distance from the walking partner. In the second evaluation the proposed method was used for a robot deployed in a shopping mall environment where it demonstrated to be effective.