Research On Robust Control And Fault Detection For Networked Control Systems

With the development of the Internet of things technology, networked control systems(NCSs) has been attended by more and more scholars in recent years, but the network-induced delays cause a decline in the performance of systems and even instability. Therefore, finding the advance control methods for the analysis and synthesis of networked control system is urgent. In addition, it has theoretical significance and extensive application value to research the robust control problem of NCSs, to find the novel approaches aiming at the parameter of controller with random perturbation, and to investigate the advanced control method for fault detection under the influence of the network-induced delays, which are also our research direction. The main task of this thesis are summarized as follows:The event-triggered robust control problem for NCSs with actuator failures and time-varying transmission delays is concerned. Firstly, a random sequence is introduced to describe the actuator faults, and a novel event-triggering communication scheme is adopted in the sensor-to-controller channel. Then, the event-triggered system is transformed into an equivalent time-delayed system by using analysis method of time delayed system. Finally, sufficient condition for the robust stability of the closed-loop system is analyzed and the robust controller is designed based on Lyapunov stability theory and free weighting matrix method.The problem is concerned with non-fragile H_∞ control for networked control systems with random parameter uncertainty of controller and time-varying transmission delays. Firstly, the probability of controller parameters perturbation is described by Bernoulli distributed random variables. Furthermore, based on linear matrix inequality(LMI) method and Lyapunov stability theory, a sufficient condition for the existence of the non-fragile controller is derived, and the controller gain can be obtained by solving a convex optimization problem. The designed controller can guarantee the stability and the prescribed H_∞ performance index in spite of the existence of the gain uncertainty and the network-induced delays.The problem of robust fault detection is addressed for networked control systems with time-varying transmission delays. Firstly, a novel event-triggering communication scheme is adopted in the sensor-to-detector channel. Then, by taking the event-triggered mechanism and network transmission delay into consideration, the original fault detection filter design problem becomes the H_∞ filtering problem. Finally, the parameter of fault detection filter can be derived by Lyapunov stability theory and LMI method.Finally, numerical examples are exploited to demonstrate the effectiveness of proposed approach by using LMI box in every chapter.