Analysis And Design For Ncs With Data Packet Dropouts

With the extension of the size of control systems and the rapid development of network technologies, networked control systems (NCSs) appeared and became a new research field in the automation. The so-called NCS is a feedback control system wherein the control loop is closed through real-time network. It has enormous advantages such as shared resources of information, reduced system wiring, facility of system extending and maintenance, higher reliability and flexibility, and so on. However, because of the introduction of the network in traditional control system, it is inevitable that there exists networked-induced delay, message collision, time sequence confusion and data packet dropouts etc. These are main factors to degrade the performance of control systems. So the NCS brings a new challenge and opportunity to the investigation of control theory.The key issue of data packet dropouts in NCS is studied in the thesis. Main achievements are as follows:First of all, the thesis considers the NCSs with packet dropouts in single-packet transmissions. A new jump linear system model is derived whose packet dropouts history is described by different independent Markov chains, sufficient condition for stochastic stability is derived and corresponding state-feedback control law is given through relevant theory. Numerical example illustrates the effectiveness of the results.Secondly, the thesis considers the NCSs with packet dropouts in multi-packet transmissions. A new jump linear system model is derived whose packet dropouts history is described by different independent Markov chains. In terms of the given model, sufficient condition for stochastic stability is derived via Lyapunov stability theory in the form of linear matrix inequalities and corresponding state-feedback control law is given. Numerical example illustrates the effectiveness of the results.Finally, we discuss modeling and control of the NCS with both network-induced delay and packet dropouts. Due to the different characters of these two issues, the NCS are modeled as jump linear system and discrete-time switched system respectively. The conditions for stability are derived and corresponding control laws are given via correlative theory. Two numerical examples demonstrate the effectiveness of above conclusions.