| Strengthening the technology of rail transit operation safety assurance and improving the quality of operation service are the new requirements of the "transportation era" for the rail transit system.As the power source of the train,the train traction system is an important part of the urban rail transit system.Once a failure occurs,it will endanger people’s lives and cause great economic losses.Therefore,in order to effectively ensure the safe operation of trains,the installation of various types of fault detection equipment in the train traction system,so as to accurately perceive the operation status of the train traction system in real time,is the core means to solve the problem of train safety detection.However,the train traction system has many components,concealed and complicated fault types,and strong internal fault relevance.How to systematically and objectively evaluate the fault coverage and diagnosis capabilities of the testing equipment,construct a reasonable diagnosis strategy,and improve the maintenance guarantee Efficiency is a fundamental problem to be solved urgently in the technical field of train operation and maintenance.In response to this problem,this article attempts to apply testability technology to the test capability analysis of rail transit train traction systems,discusses the basic theories and methods of system testability evaluation and diagnostic capability optimization,and uses multi-signal flow modeling methods on this basis.In-depth study of the failure propagation law of the train traction system,a fault propagation model of the train traction system including 28 failures and 16 tests was established,which provided model support for testability verification and diagnostic ability evaluation.Secondly,based on the fault propagation model of the train traction system,a "faulttest" correlation matrix is constructed.Based on the system fault propagation mechanism,the fault coverage capability of the existing test points of the traction system is studied from a system-level perspective.Evaluate the testability indicators such as the overall fault coverage rate,fault detection rate and fault isolation rate of the system,and evaluate the testability level of the traction system.Then,on the basis of testability analysis,the factors of actual application scenarios and failure levels are coordinated,and a test selection method of train traction system considering key failures is proposed.Firstly,construct the mathematical model expression of the test selection problem considering the key failures,and use the discrete binary particle swarm algorithm to solve the problem,and then verify the feasibility of the method through typical cases;in the test selection model of the train traction system,only 19 tests are used The point can make the detection rate and isolation rate of system faults reach 90.35%and 100%,and the detection rate and isolation rate of critical faults can reach 100%.Compared with the original complete test set,it saves 7 tests and achieves the goal of reducing test costs.Finally,in view of the uncertainty in the actual test,a method for constructing a fault diagnosis strategy for the traction system under unreliable testing is proposed.The concept of test credibility is introduced for the first time,and the quantitative evaluation of test credibility is realized through the cloud model,so as to construct a new fault-test"credibility correlation matrix;on this basis,the traction is constructed based on information theory The system’s single-fault diagnosis strategy can more reasonably and efficiently meet the diagnosis requirements in actual scenarios.There are 38 figures,38 tables and 66 references. |
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