Proportional-Integral Output Feedback Controller Design Of Networked Control Systems

Networked Control Systems (NCS) are distributed systems, which are also closed loop feedback control systems with networks existing both between sensor and controller and between controller and actuator. The main feature of NCS is that information is exchanged by using networks among control system components (sensor, controller and actuator).The development of modern industrial and commercial systems is the process to integrate computer, communication and control into machine operations and information.The introduction of network architectures can improve the efficiency,flexibility and reliability of these integrated applications, and reduce installation, reconfiguration and costs.Hence,the mechanism of network plays an important role on the stability and performance of NCS. Although NCS has the advantages of resources share, reducing system costs, increasing system agility and maintenances, network transmission causes many problems such as time-delay and data packet dropout. That not only makes it difficult to analyze the system, but also makes it difficult to apply the conventional control theories to NCS directly.Firstly,the conception and features of NCS are introduced.Some basic problems and recent development of NCS are also discussed in detail.Secondly, we study the modeling of NCS and present the models in different conditions. Main discussion is based on the model that time-delay is less than one sample period,data is transmitted in a single packet and there exits data packet dropout.Thirdly, the stability of NCS with short time-delay and data packet dropout is discussed respectively. The study mainly focuses on the stability of NCS with data packet dropout existing between sensor and controller.Fourthly, we use an estimator to reconstruct an approximation to the plant and make it available for the controller design. Then the model of NCS with time-delay and data packet dropout is analyzed and the solution of the problems is also given.Fifthly, aiming at NCS under Proportional-Integral (PI) output feedback controller with time-delay and data packet dropout existing both between sensor and controller and between controller and actuator, we model NCS as an asynchronous dynamical system constrained by configuration event rates.The condition of exponential stability of NCS whose time-delay is constant and variable is deprived by using Lyapunov stability theory, and the controller design is also discussed by using Linear Matrix Inequality (LMI).At last, the conclusions and the remaining problems of NCS are both pointed out.