Fault Diagnosis Based On Parity Space Method And Its Application

In the fault diagnosis technology based on parity space method,the selection of equivalent space matrix is an important part.In this paper,the problem of selecting parity space matrix for fault detection,isolation and estimation of discrete systems is studied by using the methods of singular value decomposition and linear matrix inequality.The main work and research results are as follows:The idea of fault detection based on parity space method is studied.Two methods,direct redundancy and analytical redundancy,are used to make the measurement output or residual unaffected by the state.Singular value decomposition(SVD)is used to optimize the equivalent space matrix,which makes the residual more robust to unknown inputs and more sensitive to fault signals.The fault isolation algorithm based on parity space method is studied.Firstly,the decoupled fault is completely decoupled,and a set of structural residual is generated for fault isolation.Because of its strict design requirements,it can not be widely used.Considering a part of the fault as an unknown input,the method of singular value decomposition(SVD)is used to make the residual robust to this part of the fault and sensitive to the remaining faults,so as to obtain the purpose of fault separation.The fault estimation algorithm based on parity space method is studied.Firstly,the knowledge about linear matrix inequality(LMI)is studied.Then,the error of fault estimation is minimized by using LMI to optimize the parity space matrix.However,LMI is widely used in linear time-varying systems(LTI).Because of its large amount of real-time computation on-line,it can not be widely used in practical linear time-varying systems.Then,the parity space matrix satisfying the minimum value of the matrix quadratic form is obtained.The model of satellite gyroscope attitude control system is established,and the fault optimization algorithm based on singular value decomposition is applied in it and compared with the non-optimization.The fault isolation simulation of XYZ three-axis fault is carried out based on structural residual.