Fuzzy-Logic-Based Reactive Behavior Control of an Autonomous Mobile System in Unknown Environments

This paper presents a method for fuzzy-logic-based reactive behavior control of an autonomous mobile system in unknown environments. Difficulties in behavior-based control arise mainly from the quantitative formulation of reactive behavior as well as from the need for efficient coordination of conflicts and competition among multiple types of reactive behavior. The main idea of the present study is to incorporate fuzzy logic control with behavior-based control such that types of reactive behavior are formulated by fuzzy sets and fuzzy rules, and conflicts and competition among different types are coordinated by fuzzy reasoning. The inputs to the control scheme consist of a heading angle between the robot and a specified target and the distances between the robot and the obstacles to the left, front, and right locations, acquired by an array of ultrasonic sensors. The outputs from the control scheme are commands for the speed control unit of two rear wheels of a mobile robot. Simulation results show that the proposed method can be applied to efficient robot navigation in complex and unknown environments by weighting different varieties of reactive behavior, such as avoiding obstacles, following edges, moving towards a target, and so forth. In addition, this method is suitable for robot navigation by multisensor fusion and integration.