A FUZZY CONTROLLER FOR A MOBILE ROBOT WITH OBSTACLE AVOIDANCE

Abstract

This research paper presents a mobile robot based on the MAMDANI fuzzy inference system. The mobile robot is equipped with three pairs of HC-SR04 ultrasonic sensors to detect the distance between the robot and obstacles. A fuzzy logic controller is built into the STM32F4 microcontroller platform to generate the actuation signal for the DC motor mounted on each robot wheel. To perform obstacle avoidance, a sensor capable of detecting the distance between the robot and the obstacle must be installed so that the controller can calculate and determine the appropriate control signal to send to the robot's actuator. In achieving this goal, the robot can perform movements at a constant speed or at a variable speed. When the distance between the robot and the obstacle is too far, the speed is too fast. Then, as the distance to the obstacle increases, the speed decreases. Such a control mechanism can be implemented with certain control methods installed in the controller. The data obtained from the ultrasonic sensors are expressed as linguistic variables that indicate the speed of movement of each wheel in fuzzy sets. A robot with a fuzzy logic controller based on a rule table is designed to achieve uninterrupted motion with obstacle avoidance capability. Keywords: STM32F4 microcontroller, Fuzzy logic, Fuzzy inference system, mobile robot, obstacle avoidance.