Distributed formation control for swarm robots using mobile agents

This paper presents a decentralized control algorithm for composing a specific formation of swarm robots. The swarm robots are expected to compose formations that represent symbols. The robots are connected by communication networks and not necessary intelligent; they initially do not have any control program to compose symbols. Control programs that implement our algorithm are introduced later from outside as mobile software agents, which are able to migrate from one robot to another robot connected by the network. Our controlling algorithm is based on the indirect pheromone communication of social insects such as ants. We have implemented the ant and the pheromone as mobile software agents. Ant agents control the robots. Each ant agent has partial information about the formation they are supposed to compose. The partial information consists of relative locations with neighbor robots that are cooperatively composing the target formation. Once the ant agent detects an idle robot, it occupies that robot and generates the pheromone agent to attract other ant agents to the location for neighbor robots. Then the pheromone agent repeatedly migrates to other robots to diffuse attracting information. Once the pheromone agent reaches the robot with an ant agent, the ant agent migrates to the robot closest to the location pointed by the pheromone agent, and then, drives the robot to the location. We have implemented a simulator based on our algorithm, and conducted experiments to demonstrate the feasibility of our approach.