Multi-agent coordination and control using stigmergy

This paper describes and discusses a novel design and a prototype implementation for manufacturing control systems, aimed at handling changes and disturbances. This novel design utilizes the concept of a multi-agent system. Agents in this system use an indirect coordination mechanism, called stigmergy. Stigmergy is a class of mechanisms that mediate animal-animal interactions. It consists of indirect communication that is taking place between individuals of an insect society by local modifications induced by these insects on their environment. The coordination mechanism in this paper is based on a technique used by food foraging ants. Food foraging ants provide the inspiration by the manner in which they spread information and make global information available locally; thus, an ant agent only needs to observe its local environment in order to account for nonlocal concerns in its decisions. A prototype was built to test the coordination technique. The prototype comprises a flexible manufacturing system model/emulation that has dynamic order arrival, probabilistic processing time, and some general perturbations such as machine breakdowns. The prototype served to investigate a specific research question: is it possible to create short-term forecasts based on the intentions of the agents. It has been intentionally kept simple to facilitate the understanding of what is happening in the system. Size and complexity of the prototype implementations are being augmented gradually in ongoing research. # 2003 Elsevier B.V. All rights reserved.