Stability Analysis Of Networked Control Systems

The network control system is an emerging discipline which along with the control technology, the network communication as well as the computer technology development, which is feedback control system wherein the control loops are closed through a control network. The advantages of NCSs are reduced system wiring, ease of maintenance and diagnosis, and increased system agility. However, the insertion of the communication network in the feedback control loop , some new issue such an networked induced time-delay, network packets dropping and network scheduling appear, which all make the analysis and design of an NCS complex. In this thesis we studied stabilization of NCSs when induced time-delay and network packets dropping are considered.Aiming at a class of NCSs with time-delay, we studied short time delay NCS and long time delay NCS separately. When time delay shorter than one sample period ,the discrete model of NCS was given. Based on the Lyapunov function, robust control theory and the Linear Matrix inequalities, the sufficient condition for the uncertain NCS which is subject to the asymptotic stability was derived. The design approach of the controller is given. When time delay longer than one sample period,based on switched theory, the switched model was given, and stability was investigated. Aiming at a class of NCSs with data packet dropout, the model as an Asynchronous Dynamical Systems was given, the sufficient condition for the exponential stability of the NCS with fixed data packet rate is derived.Last, the summary of the thesis, the future work to be investigated, and the prospect of NCSs are presented.