Our small-size robot team is a fully autonomous system consisting of a global perception system and decision-making individual clients. The team is made up of five robots that we have built [19]. Figure 2.2 shows our CMUnited-98 robots.
Figure 2: CMUnited-98 Small Robot Team: RoboCup-98 World Champions
The decision-making clients select actions based on the perceived world state and send these commands to the physical robots through radio communication. Perception is accomplished through a camera over-looking the playing field. The full view of the world is processed by our vision algorithm to find and track the position and orientation of the team's agents, the position of the opponents, and the position and trajectory of the ball [2]. This processing provides a global view of the environment that is shared by all of the agents.
Each physical robot is controlled by a separate client program that makes decisions using the information obtained from the vision system. Each agent is assigned a role and therefore behaves differently. There are three roles used in our system: goal-tender, defender, and attacker. Even with this partition of agents, it is still not desirable for all of the agents to be ``actively'' filling their roles. For example, it is rarely successful for all of the attackers to chase the ball since they will often be hindering each other's progress. Multiple attackers need therefore to coordinate. Each attacking agent uses the perceived world to calculate the value of its own and its teammates' possible actions (e.g. shooting or passing to a teammate). The agent with the highest valued action becomes active and attempts to achieve this action. The other agents become passive. These agents then act in a way to anticipate where they may be useful for future collaboration with the active agent.