Realization of flock behavior by using tau-margin

Recently, swarm intelligence has been actively studied and has been applied for various robots. Realization of flock behaviors by mobile robots is one of them. In conventional works of applications of flock behaviors, environments are modeled as three-dimensional space by using distance sensors, and flock behaviors are realized based on the distance information. However, the conventional framework can not explain mechanisms of real flock behaviors of animals like birds and so on, because most of animals do not have distance sensors and can not perceive precise distance information. To explain the mechanism, in the ecological psychology, it is considered that animals perceive time to contact called tau-margin, instead of perceiving information of distance. In this paper, we consider realization of flock behaviors using tau-margin, and develop multi mobile robots that have 10-watt light bulb and can perceive tau-margin by utilizing optical inverse-square law. To discuss the effectiveness of tau-margin in realizing flock behaviors, experiments using the developed robots have been conducted, and as the results, flock behaviors have been realized without employing any distance information.