Design Of Networked Control Systems Based On Convex Polytopic Model

With the rapid development of network communication technology, computer technology and expansion of control systems, the networked control systems (NCS) came into use. NCS is a control system of powerful advantage, excellent performance, operating efficiency, easy maintenance, and also a complex distributed control system which involving several subjects, crossing many areas and using a variety of research methods. NCS can be applied to almost all occasions of data exchange with distribution equipment controllers, and this reflects the developing trends of the control system to networking, integration, distribution and intelligent nodes. However, due to the involvement of network, in NCS there will be many problems such as the network-induced delay, data packet time series disorder, packet dropout, which will not only reduce the performance of control systems but also make the system unstable. Therefore the analysis and design of the NCS becomes very complicated. In this paper, we research the stability of the networked control systems with uncertain network-induced delay, and propose convex polytopic model to describe uncertainty of the systems. Using linear matrix inequalities (LMI) we give the conditions for the robust stability of closed-loop system, and design the output feedback controller to meet the performance requirements of the systems.Firstly, in the paper we introduce the basic concepts of networked control systems, the development and research contents of networked control theory. Secondly, we introduce real-time simulation tool TrueTime using for the networked control systems. By analyzing components and characteristics of the network-induced delay we use TrueTime to illustrate the effect of the network-induced delay on system performance. According to uncertain delay (bounded), we establish discrete system model based on convex polytopic structures. Using linear matrix inequalities (LMI) to guarantee the constraints conditons of convex polytopic, we design parameters of the dynamic output feedback controller by solving linear matrix inequalities to meet the stability requirements of the system. Finally, we do simulations with TrueTime to verify rationality and availability of the proposed method.