Technology Of Vehicle Fault Diagnosis And Decision Support

The technology of fault diagnosis is an engineering science and have closely related with production, it is widely used in the field of currently industrial, defense, etc, and is the increasingly important research content. With the increasingly high of degree of system complexity and rapid development of degree of automation, system’s failure rate also increased, the requirements of system’s reliability are also increasing. Therefore, in the future for a long time, fault diagnosis technology will become the an important research direction for the domestic and foreign experts and scholars. Use advanced troubleshooting techniques to diagnose the system, not only can effectively eliminate system failure, but also can prevent the occurrence of major accidents, avoid casualties and economic losses.In this paper, background is aerospace, in-depth study the the theory and practical application examples about "aircraft fault diagnosis technology". Mainly for the following two work done a lot of research and development:First, research on the fault diagnosis algorithm of the fault tree and directed graph, and applying this method in the actual aircraft system’s fault diagnosis; The second is based on C# software development platform complete "aircraft fault diagnosis technology". The following is attributed to the subject content and results.(1) Research on the fault diagnosis method of static fault trees. Including static fault tree’ s qualitative analysis; Based on Binary Decision Diagram of static fault tree analysis method.(2) Research on the fault diagnosis method of dynamic fault trees. One is put forward an approximate algorithm for top-event occurrence rate of dynamic fault trees based on Monte Carlo. This paper for dynamic fault tree of containing different dynamic logic gates, converts the top event probability integral multiple of different logic gates, using Monte Carlo computing approximation algorithm, analyzed a satellite solar wing on the driving mechanism of stepper motor probability of top event; The second is study the dynamic fault tree analysis method based on modular, the dynamic fault tree is divided into static sub-tree and dynamic sub-tree, with the idea of modularization Binary Decision Diagram and Markov method are respectively applied to analyze them, completed a satellite solar cell wing-photooltaic battery power system fault analysis.(3) Research on the fault diagnosis method based on Directed Graph. One is proposes a fault reasoning method based on hierarchical SDG model, adopts the hierarchical strategy, reducing the searching space fault source, using the qualitative relationship between the test node, back in the search of fault propagation path incompatible branch to find out fault source of candidates, and the candidate solution to sort; The second is in hierarchical SDG model on the basis of introduction of confused thoughts, proposes a fault reasoning method based on fuzzy hierarchical SDG model, building system’s SDG model, and layering,using fuzzy variable node variables, represented by conditional probability table qualitative causal relationship between the expression node, using bayesian inference and back in the search to find out fault source candidates, and sorting of candidate solutions. Application method,for a certain type aircraft engine fuel control system fault diagnosis.(4) Based on the C# software development platform to complete the aircraft fault diagnosis and aided decision system development. Implementation of a static fault tree.