Design of an Image-based Fuzzy Controller for Parking Problems of a Car-like Mobile Robot

摘要

With increasing number of vehicles over years, parking systems have become an important issue in commercial environments such as shopping malls and airports.For this reason, the automatic parking systems of car-like mobile robots have attracted a great deal of attention from research organization and automobile industry.In many recent works, a number of different approaches have been developed to build an automatic parking system.Most of them are still expensive for commercialization.In the middle of 80-th, the first ideas of automatic parking systems were developed.Under this topic, a fuzzy algorithm for garage parking system, a first nonlinear algorithm for parking control, and the main statements for parallel parking problem, were proposed as early researches.Most of the researches related to a parking problem are usually to find a path that connects the initial configuration to the final one by considering the nonholonomic constraints.On the other hand, a skill-based approach that used the fuzzy logic, was developed.There is no reference path to be followed by a robot and the control command is generated by considering the position and orientation of the robot relative to the parking space.An exact vehicle pose relative to the parking space is required in this approach.The automatic parking system consists of a parking lot detection module and an automatic parking algorithm.In the recent works on parking control systems, a method for detecting camera vision-based parking lots and a method which used the ultrasonic sensors to detect the parking lots, were discussed.For the experimental study of fuzzy garage parking control, the CCD camera was utilized to detect the overall vision of the parking lot, the six infrared sensors were adopted to measure the distances between the robot and the surroundings, and the sensor fusion techniques that combine the ultrasonic sensors, encoders, and gyroscopes with a differential GPS system were used to detect and estimate the dimensions of the parking lot in recent works.However, all are the expensive methods.This thesis aims to build an automatic parking system of a car-like mobile robot.The automatic parking system that corresponds to the posture stabilization problem of car-like mobile robot, is presented in the first part of this dissertation.The goal is to stabilize the car-like mobile robot to a desired final posture starting from any initial posture (posture means the combination of the position and orientation of the robot).The switching and List of tables4.1 Fuzzy rules for the steering angle, . . . . . . . . .