Method for diagnosing fault by functional fault directed graph

Abstract

The invention provides a method for diagnosing a fault by a functional fault directed graph, which can be applied to the field of fault diagnosis for some systems of aircrafts (such as an air source system, an anti-icing system and an air-conditioning system of an airplane gas path). The method comprises the steps of: decomposing a diagnosis object system to determine component relation and build a system structural model, confirming the corresponding input and output based on the component functions, determining the component fault model, analyzing fault propagation path and influence relation, setting test points and test information of a sensor, monitoring parameter variation that indicates the potential fault, forming an FF-SDG model, and at last, searching the potential fault source by a hierarchical policy inference method based on the FF-SDG model to perform fault diagnosis. The method can quickly and effectively find out the system fault source of the aircraft system, discover the fault cause, and make up shortage of the fault diagnosis technique based on manuals and cases when some fault cannot be predicated and the knowledge is difficult to be acquired by domain experts.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis and analysis of aircraft, and provides a set of fault analysis, modeling and diagnosis methods for complex systems when some faults in this field are unpredictable and it is difficult for domain experts to acquire knowledge. Background technique [0002] Some aircraft systems (such as air source system, anti-icing system, and air conditioning system) of the aircraft air circuit have frequent, repetitive, and complex faults, which require convenient, fast, and effective fault diagnosis methods. Currently, manual-based and case-based can only diagnose failure modes that are predictable or for which detailed characterization has been established. However, in the early stage of aircraft operation, there is a lack of cases for emerging faults, and due to the complexity of aircraft systems, some faults cannot be predicted, and it is difficult for domain experts to acquire knowledge, and it is di...

AI Technical Summary

Problems solved by technology

In addition, the traditional SDG model only reflects the causal relationship between process variables, lacks a description of the system structure, cannot clearly reflect the connection relationship between components and the level of fault propagation, and it is difficult to locate system faults and determine the scope of fault diagnosis in large-scale system diagnostic reasoning

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