Uncertain Networked Control Systems With Robust Fault Tolerant Control

Networked control systems (NCS) is a kind of closed-loop control system wherein the control loops replaced the traditional point-to-point connection by communication network. Focus on the situation of the existence of uncertainty time delay, data packet dropout and outside disturbances, the problem of fault-tolerant control in the NCS with failures of actuators or sensors is studied in this dissertation. The main tasks as follows:(1) Based on the Lyapunov stability analysis and the H_∞control theory, the problem of robust fault-tolerant control in the NCS with uncertainty time delay is studied. The system with and without outside disturbances are considered respectively. The state feedback controller is designed to ensure the system stability with failures of actuators or sensors. The simulations show the effectiveness and feasibility of the method.(2) Considering the existence of uncertainty time delay and data packet dropout, the NCS is modeled as asynchronous dynamical systems. Based on the theory of asynchronous dynamical systems, the problem of robust fault tolerant control of NCS with time delay and packet dropout is studied, and the NCS with unilateral and bilateral network are considered respectively. The approach of controller design is given through the linear matrix inequality, and such method makes sure the NCS asymptotic stable with the failures of actuators or sensors. The simulations verify the effectiveness of the method.(3) Based on the Lyapunov stability analysis and the method of LMI, the problem of robust guaranteed cost fault-tolerant control of NCS is studied, and the system with and without outside disturbances are considered respectively. The controller can be obtained with linear matrix inequality, which can not only enable the system stability, but also guarantee the value of the cost function not exceed a certain determinable upper bound. The simulations are given to illustrate the feasibility of the method.