balance and basic mobility. Consequently, this agent model is not as fully featured as a human-sized biped soccer playing robot would be. For example, Soccerbot has an omni-directional camera mounted in the torso and consequently the head is fixed. Similarly the hip joints are restricted to rotations around perpendicular axes. Soccerbot was also designed within certain limitations of the simulation system at the time. As the simulator became more robust, more sophisticated robot models were possible. Nao Robot The current robot model used in competitions is based on the Nao robot by Aldebaran Robotics. It has 22 hinges to control the motion of its body. Nao has a directional camera mounted in the head. The head can rotate through two degrees of freedom, ranging -120 to 120 degrees left-to-right, and -45 to 45 degrees down-to-up. The camera has a field of view 120 degrees wide. Nao also has a more complex hip structure. Perceptors The Nao robot player is equipped with various perceptors: GyroRatePerceptor delivers information about orientation relative to X,Y,Z axes. Nao has one fixed within the torso. HingeJointPerceptor provides the current angle of a hinge joint. Hinge joints can only bend along one axis. Nao has 22 such joints. ForceResistancePerceptor provides information about the location, direction and magnitude of a force applied upon a part of the body. Nao has one of these on the sole of each foot. Accelerometer measures acceleration along X,Y,Z axes of the body part to which it is affixed. Gravity is registered. Nao has one fixed within the torso. VisionPerceptor a specialised camera that reports upon the location of certain landmarks upon the field, the ball and other players. Positions are reported in polar coordinates relative to the gazing direction of Nao. GameStatePerceptor detects game time and play mode (before kickoff, free kick, game over, etc.). HearPerceptor detects messages sent from other agents on the field, reporting their distance, direction and the message itself. The simulation platform, SimSpark is capable of extension via custom perceptors, but this is not allowed in competitions. Effectors CreateEffector is sent once after the agent connects to create a robot within the server. HingeJointEffector specifies that a given force should be applied to a particular hinge joint. Nao has 22 such hinges. BeamEffector is used to reposition the robot player at times in the game when this is allowed. SayEffector makes the robot say a message that may