Fault diagnosability analysis method applicable to affine nonlinear system

Abstract

The invention discloses a fault diagnosability analysis method applicable to an affine nonlinear system. Through mathematical manipulation, a closed loop system considering nonlinear factors such as friction can be converted into a type of affine nonlinear system. By aiming at the type of system, the definition and the criterion of the fault diagnosability (including detectability and isolability) are given on the basis of the differential geometry theory; two kinds of quantitative indexes are respectively designed by aiming at the fault detectability and isolability; according to the indexes, the fault diagnosability analysis of the nonlinear closed loop system is realized through controlling the distribution conditions of output / output quantity and a mathematical model of the system. The fault diagnosability analysis method has the advantages that the fault diagnosis of the nonlinear closed loop control system can be brought forward to the design stage under the condition of not relying on any fault diagnosis algorithm, and in addition, the theoretical basis is provided for the design of the fault diagnosis algorithm.

Description

technical field [0001] The invention relates to a fault diagnosability analysis method applicable to an affine nonlinear system, which belongs to the field of satellite control. Background technique [0002] The control system is an important subsystem to realize satellite attitude, orbit control and drive of various components (such as solar wings, space-borne antennas, etc.). Due to the many moving parts and complex working modes, the on-orbit failure rate is high. According to statistics, in the 32 years from 1975 to 2007, the control system accounted for 37% of the failures of 272 satellites. Considering the importance of the control system's mission, once it fails, it will have very serious consequences. In order to ensure that the fault impact of the control system is minimized, it is necessary to consider the fault diagnosis capability of the satellite in the design stage. The level of fault diagnosis ability of control system depends on two aspects: diagnosability ...

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Problems solved by technology

However, the above techniques have the following problems: 1) The research objects are all linear systems

Therefore, in order to analyze the diagnosability of system faults caused by such nonlinear factors, various nonlinear factors must be considered to carry out refined modeling of the system; 2) The analysis results are qualitative, which can only explain whether the fault can be detected Diagnose without specifying how easily the fault can be diagnosed

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