Design And Research On The Module Of Avoiding-obstacles For Autonomous Mobile Robot

It will face uncertain environment on the move for autonomous mobile robot. How to find obstacles effectively and the realization of safe obstacle avoidance become a hot research question.Based on the homemade four-wheel vehicle, with 8-bit singlechip, AT89C52 ATMEL corp, as control kernel, obstacle avoidance module was developed. It was made up of singchip, infrared sensor net, ultrasonic sensor net and electromotor closed-loop drive control module. Do some work on constructing the distributed application about singlechip based on serial bus and communication between singlechip and PC.That is prepared for system expansion and secondary development.Eight ultrasonic sensors, which are distributed equally in a circle, form a simple sonar ring. Emitters and receivers are staggered. The detection of blind area caused by distribution is completed by infrared sensor net. About ultrasonic distance measurement, cycle emission is used to reduce echo interference. 2 receivers next to it are in a state of receiving after 1 emitter sends ultrasonic. This provides multi distance information for robot in one direction. Multi denotation methods of distance information are given. Some measurement errors are reduced by way of software. Infrared sensor net outputs digital signals, which show the information of adjacent obstacles.Electromotor closed-loop drive control module controls 2 main drive electromotors to make mobile robot avoid obstacles. The things about it are as follow: velocity feedback, H-bridge drive and speed control system using PWM technique. In hardware, pulse jitter suppression circuit is applied during velocity measuring, The core of PWM modulator is 8253.In software, PID arithmetic is used to control speed, T and variable M/T synthesis method is taken to measure velocity.The reliability of environment information is improved by pretreatment. Furthermore, fuzzy processing is taken. The fuzzy controller makes distance information become fuzzy logic and makes a conclusion to guide mobile robot to avoid obstacles by fuzzy reasoning.