A Spread Spectrum-based Sound Localization System And Its Application To Robot Navigation

Nowadays,the intelligent robots are rapidly gaining popularity in human's daily life,especially the general-purpose mobile robots are widely used in industrial handling,agricultural automation and service industries.For a mobile robot application,how to precisely locate its position in the environment is the most important function and also the prerequisite of robot autonomous navigation.As a result,developing a low cost,accurate and robust positioning system is of great significance to the application and popularity of mobile robots.This dissertation studies the positioning and navigation technology in the autonomous mobile robot and introduces a spread spectrum-based sound location system and its application to robot navigation.This system has the characteristics of low cost,high precision and scalability.In this dissertation,acoustic positioning technology is adopted to reduce the cost of the robotic system,and spread spectrum technology is introduced to improve the accuracy and anti-interference ability of the acoustic positioning system.In the second chapter,the main principle,framework of the spread spectrum-based sound location system and its related key techniques are introduced in detail.Through the static positioning experiment,we can conclude that the positioning accuracy of the system can reach about 10 cm in the range of about 8 square meters.Then,the spread spectrum-based sound location system is applied in the dynamic tracking application of the mobile robot.In order to realize the reliable positioning of the robot during the movement,the multi-sensor fusion technology based on the extended Kalman filter is adopted.In chapter 3,the kinematics model and the dead reckoning formula of the robot are established.Then,the relative position obtained by dead reckoning and theabsolute position acquired through sound location system can be fused by EKF algorithm.The result of simulation shows that the fusion location technology can effectively improve the reliability of positioning.In order to realize the autonomous navigation of mobile robot,besides the ability of accurate and reliable positioning,an obstacle avoidance system is also necessary.In this dissertation,an ultrasonic obstacle avoidance system and the behavior-based navigation control method are proposed to achieve the obstacle avoidance and navigation function.The application of ring-shaped ultrasonic sensor array and fuzzy control methods can effectively improve the ability to navigate autonomously in unknown environment.At last,a mobile robot is constructed,and the positioning system as well as the obstacle avoidance navigation system is integrated into the robot platform.The result of experiments indicates that this system has achieved the ability of autonomous navigation and positioning.The innovation of this dissertation is the introduction of spread spectrum technology to the positioning applications,which make it possible to achieve high-precision positioning using low-cost acoustic technology.Besides,the application of spread spectrum-based sound location system could dramatically reduce the cost of the robot system and largely promote the popularity of mobile robot.On the other hand,this system still has a lot of room for improvement.In the next stage,we can improve the algorithm to further improve the positioning accuracy of the system.