Study Of Fault-Tolerant Control Of MIMO Networked Control Systems

With the rapid development of the control systems, networked control systems(NCSs), such as manufacturing equipment, transport equipment, robotics and so on, are also increasingly in-depth studied, and gradually become one of the focus issues in current international control field. The control unit exchange information through the network and share network resources in time division multiplexing way in the network control systems. For the network control systems with widely distributed in space and a high degree of complexity, the network bandwidth limitations and improper scheduling algorithm result in time delay, data packet dropouts and out of order during transmission. These issues may not only reduces the real-time and reliability of information transmission, but also deteriorate the control performance of the network control systems and even cause systems instable, which make the analysis and design of network control systems complex. Therefore, NCSs have received considerable attention by researchers at home and abroad. And the research in network-induced time delays and data packet dropouts obtains some results, but the research about fault-tolerant control of multiple-input and multiple-output(MIMO) networked control systems is much less, In modern society, NCSs is full of all areas of society, for example, management decision-making, resource sharing, automated manufacturing plants, power plants, robotics, advanced aerospace aircraft and electrical transport equipment and many other high-tech sector and large enterprises, and the practical application of MIMO networked control systems is also widespread, In the actual control systems, it is great significant to ensure the stability of MIMO network control system with sensors and actuators failures. Therefore, it is necessary to study the fault-tolerant control of MIMO networked control systems.This paper, based on the understanding of various problems in MIMO networked control systems, carefully analyses the reasons of network-induced time delays and data packet dropouts. Aiming at the discrete controlled object, it gives two discrete mathematical models using the theory of fault-tolerant control and switching systems, analyzes the models using Lyapunov function and linear matrix inequality approach, and deduces the asymptotically stable sufficient condition of the closed-loop systems, as well as the co-design method of observer and controller and design method of controller. Finally, it gives a numerical example to illustrate the effectiveness of the method. The main results are summarized as follows:At first, this paper uses the theory of fault-tolerant control and switching systems. Assuming that the network-induced time delay is less than one sampling period, the systems are modeled as discrete linear systems with the sensors and actuators failures, the stability theorem is proved through utilizing the Lyapunov function and the co-design method of observer and controller and design method of controller is derived by solving the linear matrix inequalities. The resulting fault-tolerant control of MIMO networked control systems is found. Simulation examples show that the feasibility of the method.What is more, aiming at the distributed time-delay and bounded input of MIMO network control systems, the discrete-time mathematical model of the state feedback systems is established. The sufficient condition of delay-dependent asymptotical stability and the maximum allowable delay bound for the system are derived through utilizing the Lyapunov function and linear matrix inequality method, and this maximum allowable delay bound can also be used as a reference basis for selecting each sensor sampling period. Simulation examples show that the feasibility of the method.