Research On Obstacle Avoidance And Path Planning For Mobile Robots

In recent years, the research and development of mobile robot have already attracted more and more attention. People require that the capacity to take appropriate measures autonomously according to the surrounding environment of robot should be better and better. Therefore, as an important factor in intelligent robot—obstacle avoidance and path planning is particularly important, it is a key technology of robot research, and it is the premise of other advanced tasks of the robot.Mobile robot detects the external environment information through the sensing system,after processing the information, the robot plans a route to move and avoids obstacles during the walking process. This paper studies obstacle avoidance and path planning of mobile robot on the self-made wheeled robot, mainly as follows:First, the traditional artificial potential field method is analyzed and researched. Artificial potential field method with its simple structure, intuitive and easy to real-time control characteristics, and it has been used widely, but this method itself also exist the inherent defect, i.e. the local minimum points problem. Inspired by the potential field function of traditional artificial potential field method, aiming at these local minimum points problem, define artificial potential field function under new rules, namely improved artificial potential field method, this method can overcome these local minimum points problems existing in the traditional artificial potential field method.then analyze the obstacle avoidance control,including information acquisition and processing, environmental information classification, selecting principles of safe obstacle-avoidance distance analysis of avoiding front and side obstacles.Secondly, the hardware circuit of obstacle avoidance system is designed mainly on the FPGA, including the design of FPGA smallest system board,the selection of GPS positioning module and magnetic sensor,the design of ranging circuit and motor drive cercuit.and it uses GPS and terrestrial magnetic sensor to measure the position and heading information of the robot; The design of ranging circuit is to obtain robot's surrounding environment information,including the design of ultrasonic launching circuit,ultrasonic receiving circuit and the selecting of infrared ranging module. Using the SOPC technology to construct systema, including constructing and adding basic modules, the design of self-designed modules. To share the burden of Nios II and to obtain precise center frequency and accurate timing,the paper optimize the obstacle avoidance system, including the opimization of ultrasonic ranging module and infrared ranging module.The paper designes the software part including the data acquisition and processing procedure of GPS positioning sensor module and terrestrial magnetic sensor, the design of motor control software, as well as the design of obstacle avoidance and path planning procedure.Finally, using Matlab to simulate artificial potential field method, the simulation result shows the method by modifying the direction of repulsion which is based on the modified potential function can resolve the three local minima problems of the traditional artificial potential field. And in more complex environment, the robot also can arrive at the target safely without collision,and guaranteed the path is the shortest. The system carries out the obstacle avoidance and navigational experiment, whose result shows that the robot can achieve real-time obstacle avoidance at the situation of uncomplicated environment; and the robot with the help of GPS and terrestrial magnetic sensor can always advance toward the target point direction and reach the target point.