We propose a tracking control of a nonholonomic wheeled mobile robot using variable structure systems. The posture of the mobile robot is represented by polar coordinates and a sliding mode control algorithm is presented for asymptotically stabilizing the mobile robot to a desired trajectory. It is shown that the proposed scheme is robust to system perturbations and measurement errors. Simulation and experimental results confirm the validity of accurate tracking capability and the robust performance of the proposed scheme.

The soccer robot system consists of multi agents, with highly coordinated operation and movements so as to fulfill specific objectives, even under adverse situation. The coordination of the multi-agents is associated with a lot of supplementary work in advance. The associated issues are the position correction, prevention of communication congestion, local information sensing in addition to the need for imitating the human-like decision making. A control structure for a soccer robot is designed and several behaviors and actions for a soccer robot are proposed. Modified zone defense as a basic strategy and several special strategies for fouls are applied to SOTY and MIRO teams for MIROSOT (Micro-Robot World Cup Soccer Tournament).