Research Of Tracking Control For Autonomous Intelligent Agents

21st century Autonomous Intelligent Agents have been widely concerned as therespresentative of the robot systems. Wheeled Mobile Robots (WMRs) andAutonomous Underwater Vehicles (AUVs) are typical ones of them. WMR and AUVcan autonomously perform complex tasks both on land and in water, respectively.They are widely used in civil, industrial and military fields. In the seabed oil pipelineand sunmarine cable detection, topograph detection, ocean observation and militaryapplications, intelligent agents should track a specific curve efficiently and accurately.It is of significant in reseaching the tracking control of autonomous intelligent agents.AUV is a class of complex nonlinear systems, mutual coupling between the statevectors. This increases the difficulty for the control of AUV. The major results andinnovations of this dissertation are summarized as follows.1. The point stabilizaion of WMR and full-actuated AUV are discussed. First, thesystem equations are established in polar coordinates. The designing methods ofkinematic controller are obtained. Next, the kinematic controller is extended todynamic controller through Lyapunov methods and Backstepping combined with thedynamic characteristics of the system. The smooth control laws are designed. Thesimulation results show the effectiveness of the control method.2. The parking problem of WMR in finite time is proposed. The control objectiveis to make the robot stop in a pre-given parking area. Based on the nonlinear motionmodel of the robot in polar coordinates, the motion control system of the robot isdivided into two types. The two types are the linear system of rotation and the weaklynonlinear system of rectilinear motion together with rotation. The switching controllaws are obtained through Lyapunov designing method. The control laws guaranteethe robot reach a given parking domain in finite time. The estimatin formula of thefinite time is obtained. A simulation example illustrates the effectiveness of the designing method.3. The problem of adaptive trajectory tracking control for WMR and the problemof trajectory tracking control for underactuated AUV based on cascaded method isresearched. There is a distance between the mass center and the geometrical center ofthe WMR. The tracking error system is divided into two subsystems. They are theposition and the orientation error system. Backstepping technique and Lyapunovmethod are applied to design the position tracking controller. Lyapounov method isapplied to design the orientation tracking controller. An adaptive tracking control lawis proposed to deal with the circumstance with the unknown parameters for WMR.The stability of the system of trajectory tracking is ensured. The designing method oftrajectory tracking controller for the underactuate AUV on the horizontal plane in thepresence of ocean currents is obtained. The adjustment methods of some controllerparameters are derived.4. The bottom-following control problem of underactuated AUV in the presenceof ocean currents and uncertain parameters is proposed. The Serret-Frenet frame isused to describe the bottom-following of the AUV. An extra degree of freedom forcontroller design is introduced. It make the virtual AUV can regulate its velocityalong with the real AUV. Based on Lyapunov method and Backstepping techniques,an adaptive controller is designed to ensure that the AUV converges to the desiredpath asymptotically. Different terrain simulations and effect diagrams are given toshow the effectiveness of the proposed controllers.5. Delay-dependentH∞control for nonlinear AUV is researched. Bysimplifying the Fossen’s six degrees model of AUV, the AUV’s four degrees model isobtained. The uncertain time-delay system is built through taking into accout theeffect of time delay and ocean currents, waves and other factors. Linear matrixinequality (LMI) and integral inequality techniques are applied to derivedelay-dependentH∞control laws. Simulation results illustrate the effectiveness ofthe control methods proposed.