Study On Linear And Nonlinear Networked Control System And Its EE Applicaiton

The networked control system(NCS), that closes control loops by network communication,becomes a promising field due to its obvious merits, and also a challenge to the system designers dueto its problems aroused from its inherited characteristics, thus needs to be comprehensively studied.Based on the author's work experience, the dissertation attributes some electrical engineering objectsto two types of system, i.e. linear time-invariant controlled plant and Lurie nonlinear controlledplant,and puts the focus on the control problems such as modeling, stabilization, guaranteed costoptimal control, H∞optimal control, absolute stability, etc.The main points of the dissertation may be summarized as following:For the NCS of a linear time-invariant controlled plant that is of clock-driven sensor nodes,event-driven controller and actuator nodes, and with uncertain network induced delay less than orequals to a sampling period, the modeling, robust stabilization, guaranteed cost optimal control, andH∞optimal control under noise of the state feedback NCS are studied based on the Lyapunovapproach and linear matrix inequality. The system is modeled as a discrete time-variant system withuncertainty, and the condition of robust stability, the design methods for robust control, guaranteedcost optimal control and H∞optimal control are presented respectively.For the NCS of a linear time-invariant controlled plant that is of clock-driven sensor andcontroller nodes, event-driven actuator nodes, bounded time-varying network-induced delay and datapacket dropout, the NCS can be modeled as an equivalent system with time-varying delay. By usingthe Lyapunov-Krasovskii functional and linear matrix inequality, the design of state feedbacksuboptimum and optimum H∞control can be achieved with fewer variables, needless of tuningparameters and calculation iteration.The absolute stability of the state feedback NCS is studied for the Lurie nonlinear controlledplant wherein the random time-varying network-induced delay exists. The system is first modeled asa delay Lurie system, and then by using Newton-Leibniz formula and the method of adding freeweighting matrices, a delay-dependent stability condition is deduced and the method to solving thegain matrix of the state feedback controller is developed.For the study on the absolute stability of dynamic output feedback NCS applied to Lurienonlinear controlled plant, where exist random and time-varying network-induced delay, data packetdropout and data packet disorder, the system is first modeled as a Lurie system with multiple delays,and the delay-dependent stability condition is deduced by adding free weighting matrices. By addingan equation constraint, the system is transformed into a solvability problem described by linearmatrix inequality, and then the dynamic output feedback control law is then obtained.The dissertation performs theoretical verification and controller synthesis for the above mentioned results. The controlled plants such as DC drive system are used in simulation study andthe simulated results validated the effectiveness of the designed controllers. A summary withprospective outlook is at the end of the dissertation.