Analysis And Control Of Networked Control System With Time-delay And Data Packet Dropout

With the rapid development of science and technology, Networked Control System (NCS) is generated. NCS is a distributed real-time feedback control system of realizing the sensors, controllers and actuators to exchange data through a communication networked transmission medium. Meanwhile, the NCS has the resources sharing, long-distance distributed control and other advantages. The NCS is applied in many areas. However, when the system exchanging data through the network, transfer delay and data packet loss are often caused by the system nodes sharing the limited network bandwidth and communication mechanism. Therefore, the system performance is reduced, even causes the system instability. Three main research works have been done as follows:(1) Aim at time-delay networked control system, the time-delay is divided into a fixed time-delay and arbitrary time-varying time-delay. By the time-delay golden cutting and introduction of the improved free-weighting matrices, based on the Lyapunov stability theory, a new method of discussing the stability of networked control system is presented, and a less conservative asymptotic stability criterion is obtained. Finally, according to the two stability criterion, the convex optimization is solved by the linear matrix inequalities toolbox, and the maximum allowable delay is designed.(2) Aim at time-delay networked control system, the control law design is considered. In the design of the state feedback control law, the time-delay is divided into the transfer delay lower bound and the time-varying delay. By introducing a equality constraint condition, then bilinear matrix variable is avoided. Thus the condition for solving the state feedback control law is simplified. Moreover, by introducing the transfer delay lower bound, a less conservative result is obtained. Finally, using time-delay-dependent approach, output feedback control law and the maximum allowable delay are designed. Based on the Lyapunov stability theory and improved free-weighting technology, any cross terms are not enlarged. Moreover, the less conservative conditions for solving the output feedback control law and calculating maximum allowable delay are obtained.(3) Aim at data packet loss networked control system, the state time-delay is considered. The system is equivalent to the switching system. Based on Lyapunov stability theory and switching system theory, observer-based state feedback control law is designed. The linear matrix inequality conditions are established by Matlab Toolbox.