Nonlinear Control System Design Of Mobile Robot Via Visual Information

Autonomous navigation of mobile robot is the focus of much of the current research in the field of robotics. During a navigation task, a robot must answer three questions:Where am I? What the world looks like? and How to reach a desired place? Visual servoing of mobile robots, of course, as one of the most important part of the mobile robot navigation system, can successfully solve the problem "What the world looks like?" and "how to reach the desired place?"This thesis develops the conventional camera as the sensor of the mobile robot, and we use the visual information from the camera as the feedback information which will be used in the design of the nonlinear control system of the mobile robot. In the field of the computer vision, this thesis pays much attention on the research of the multiple view geometry. And we choose the fundamental matrix to express the geometry constraint between two picture acquired from the two different view. Normalized eight points algorithm is chosen to estimate the fundamental matrix. Then, this thesis fully explores the theory of the Active Disturbance Rejection Control Technique (ADRC) and the theory of the Sliding Mode Control (SMC), and we develop the nonlinear controller of the mobile robot based on ADRC and SMC theory. And three nonlinear control system of mobile robot are developed in this thesis. Now the content of this thesis is summarized as follow:(1) Normalized eight points algorithm is introduced in full detail and tested by the MATLAB simulation which proves that the algorithm is fast and accurate. And the robustness of the algorithm is tested by the real experiment in which noise exists.(2) Lateral controller of mobile robot based on the theory of ADRC is designed, which is tested under the environment of simulink of MATLAB. Effectiveness is proved through the simulation. Yaw angle controller of mobile robot is also developed on the theory of ADRC, and effectiveness and robustness of the system is proved through the MATLAB simulation.(3) Visual control system via multiple view geometry is designed on the nonlinear theory of Sliding Mode Control. And the stability of the system is proved through Lyapunov approach. Then the effectiveness and robustness of the visual servoing system is tested by the simulation under the environment of MATLAB.At the end of this thesis, work carried out in the thesis is reviewed and further research in this field is prospected.