Fault Detection Study Of Networked Control System

With the development and application of control science and network technique, the safety and reliability of the control system are increasingly important. The fault detection can discover and alarm when the control system having fault. The fault detection has become one of the important techniques to ensure the system steady run and safety and reliability. Nowadays there are some successful applications in industrial production.The networked control system is feedback control system based on communications network transmiting data. It is flexible, low cost in installing and convenients for maintenance. Unlike the tradition control system, time-delay and dropout of network communications reduce capability and stability of closed loop system. The thesis is concern with the fault detection of networked control system considering time-delay and data-packet dropout.Firstly, the intention and significance of fault detection techniques and networked control system is introduced and interrelated methods have been summarized. The orientation in this area is also pointed in the thesis.Secondly, the basic knowledge is introduced, such as linear matrix inequalities and matlab toolbox. The mathematics model on fault of networked control system is given and the uniform model of the networked control system with different style faults is proposed.Thirdly, the problem of fault detection of networked control system is studied based on asynchronous dynamic system. The fault observer is designed respectively and the error equation of the observer is deduced and the stability condition of error system is given based on asynchronous dynamic system knowledge. The result of simulation verifys the effectiveness of the proposed method.Finally, the problem of fault detection of networked control system is studied based on switched system. The model of networked control system with data-packet dropout is transformed into the model of switched system with multi-subsystem. The fault observer is designed respectively aiming at different subsystem and the error equation of the observer is deduced and the stability condition of error system is given based on switched system knowledge. The result of simulation verifys the effectiveness of the proposed method.