Research On Fault Detection And Fault Tolerant Control For Networked Control Systems

The fault detection and fault tolerant control methods for networked control systems (NCSs) with time-delay are studied in this dissertation. The proposed methods are simulated by Matlab software.At first, the current progress and meaning on the study of networked control systems (NCSs) are surveyed in this paper. Also, the progress of fault detection (FD) and fault tolerant control (FTC) for NCSs is introduced and some conclusions are given.Based on the analysis of general model for NCSs, with some mathematic transformation, the time delays of NCSs can be regarded as an unknown input. Using the unknown input observer (UIO) design method, the sufficient condition for stability of the error dynamic system is given in terms of linear matrix equations. Under the designed unknown input observer, an output residual is constructed to detect the system fault. Then a numeral example is illustrated to validate the effectiveness of the proposed method.Furthermore, a new approach of the output feedback model reference adaptive control for NCSs with time-delays is developed. A Smith predictor is used to reduce the effect of time-delay with predigesting the model of system. Then, an output feedback model reference adaptive control (MRAC) scheme is designed. The controller of MRAC can not only guarantee the stability of the closed-loop system but also preserve a given level of performance when circumstance changes or a fault occurs. Finally, simulation results are included to show the efficiency of the proposed scheme.Finally, under the analysis of some general virtual instrument software, a scheme for virtual NCSs simulation platform is constructed based on the LabWindows and the Matlab.