Keeping of Flock Behavior by Using Time to Contact Called Tau-Margin (Application to Multi Mobile Robots That Have a Light Bulb)

Recently, control of multi mobile robots has been actively studied and has been applied for various applications. 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 cannot explain mechanisms of real flock behaviors of animals like birds and so on, because most of animals do not have distance sensors and cannot 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 control mechanism for keeping 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 keeping flock behaviors, experiments using the developed robots have been conducted, and as the results, flock behaviors have been maintained without employing any distance information.