The small-size robot league setup is viewed as an overall complete
autonomous framework composed of the physical navigational robotic
agents
, a video camera over-looking the
playing field connected to a centralized interface computer, and
several clients as the minds of the small-size robot players.
Figure 2 sketches the building blocks of the
architecture.
Figure 2: CMUnited Architecture with Global Perception and
Distributed Reaction.
The complete system is fully autonomous consisting of a well-defined and challenging processing cycle. The global vision algorithm perceives the dynamic environment and processes the images, giving the positions of each robot and the ball. This information is sent to an off-board controller and distributed to the different agent algorithms. Each agent evaluates the world state and uses its strategic knowledge to decide what to do next. Actions are motion commands that are sent by the off-board controller through RF communication. Commands can be broadcast or sent directly to individual agents. Each robot has an identification binary code that is used on-board to detect commands intended for that robot. This complete system is fully implemented.
Although it may be possible to fit an on-board vision system onto robots of small size, in the interest of being able to quickly move on to strategic multiagent issues, we have opted for a global vision system. (In a future version of our robots, we may investigate distributed vision issues and incorporate on-board vision.)
The fact that perception is achieved by a video camera that over-looks the complete field offers an opportunity to get a global view of the world state. Although this setup may simplify the sharing of information among multiple agents, it presents a challenge for reliable and real-time processing of the movement of multiple moving objects--in our case, the ball, five agents on our team, and five agents in the opponent team.
This section focusses on presenting our vision processing algorithm whose accuracy makes it a major contribution towards the success of our team.