Design of fuzzy control applied to the path following of Lego-NXT system

With a auxiliary wheel, the Lego-NXT mobile robot, is a small two-wheeled and a mobile platform, which is controlled by a ARM7 microcomputer. The robot could sense its surroundings with the ultrasonic sensor, distinguish the reflected light intensity with the light sensor and move it forward by two DC motors. Robot behaviour was determined by the program which was made by fuzzy control theory and loaded to the ARM7 microcomputer. In that way, it could be used as a general robotics fuzzy control theory experimental perform. In this paper it´s shown that the path following robot with light sensor is used under the robot to sense a black line drawn on a white surface and a fuzzy logic algorithm is used to move the robot to follow the line. The predefined path is having varied turns, the fuzzy reasoning take care of power between two DC motor to keep Lego-NXT mobile robot in the pre-defined path. The results are proved experimentally and fuzzy control theory for stability is verified by Mat Lab utility. Hardware details of the robot and the software implementing the fuzzy control algorithm are given in the paper.