The Study Of Mobile Robot Navigation System Based On The Fusion Of Vision And Ultrasonic Sensor

The technologies of mobile robot navigation which is comprehensive, complicated and developed continuously is the kernel technique for robotic intelligence. These technologies mainly include environment information collection, environment information understanding, environment information modeling and thereby the path planning for autonomous navigation. Therefore, the research on the navigation system of mobile robots is organized in these steps: choose the corresponding sensors for the special environment, choose the proper environment model according to the information features of sensors, and lastly build a path planning algorithm for the selected environment model. It has become a hot field to research and design the computer vision based autonomous mobile robot navigation in the past few years. Images describe roundly the environment, and carry a tremendous amount of information about the scene the robot represents. It is the important artifice for robot to explore the surroundings. The dissertation is mainly focus on robotic landmark recognition algorithm in a known environment and multi-sensor data fusion. Both the simulation result and the experiment data gained from mobile robot navigation system are provided in the dissertation.We firstly give a brief overview to the development of autonomous mobile robot and the status of motive robot vision system investigation. Then introduce the classification of various sensors, and how to choose the appropriate sensor for the environment information. Comparing each kind of sensor, we choose the ultrasonic sensor and the CMOS vision sensor to compose the robot sensor system.This dissertation introduces the principle of CMOS sensor,the method of data processing, and discusses the processing and recognition of the obtained landmark picture deeply. Namely the influences of scale factor to Hu's moment invariants in discrete situation are investigated and present an improved algorithm of moment invariants to extract the object's character for object recognition. Thus upgrades the landmark recognition to the level of all traffic signs recognition. Simultaneously, this dissertation also introduces the principle of ultrasonic sensor,the application method,the method of data processing, and uses the ultrasonic sensors to detect the obstacles which are in front of the robot,on the left side or on the right side, then fuses the information of vision and ultrasonic sensor with the method of Neural Network, and realizes the robot intelligent navigation through the technology of multi-sensors information fusion in the obstacle environment.Finally, mobile robot navigation software in VC++ environment is designed and realized with the help of WiRobotX80 ActiveX controller. Such essential technology as off-line constructing sensing model, map data designing, vision data process, and landmark recognizing algorithm and so on can be realized by this software. And navigation experiment in structural environment is implemented. Experiment results and further experiment data analysis show the method's validity, robustness and practicability.