Testability Virtual Verification Technology Based On Modelica

Testability is a crucial characteristic of equipments which can timely andaccurately determine the equipments’ working status(can work, can’t work orperformance degradation), it plays an important role in the equipments’ maintenance.Because of the importance of testability, it should be verified during the process ofdesign, production, stereotypes, receiving of equipments. The definition oftestability verification is using method provided by testability design to evaluate thetestability level of the equipments, and decide whether to accept the equipments.Usually, the method of testability verification is testability physical verification, itevaluate equipments’ testability by inject faults into the real equipments and collectthe test data. There are many shortcomings of this way, such as high risk anddifficulty in fault injection, long verification period, high verification cost and so on.As the development of computer technology and M&S(modeling and simulationtechnology), the concept of testability virtual verification raised. The definition oftestability virtual verification is using computer technology and M&S to build thedigital model instead of all or part of the real equipments to do the testabilityverification experiments, collect statistics and evaluate testability. It has theadvantage of fault injection easy, low cost, short time, etc. So, it’s important to doresearch about testability virtual verification.In this paper, through deep study in the technology process of the testabilityvirtual verification, a new architecture of testability virtual verification is raised. Itconsists of testability virtual verification modeling, fault samples generation, faultfeature extraction and analysis. On this basis, testability virtual verification softwareis developed. The major contents of this paper are as follows.Firstly, do research on the method of testability virtual verification modeling.Combine the hierarchical modeling and FSFTC mixed modeling to conducttestability virtual verification model, lay down the foundation of testability virtualverification.Secondly, do research on the fault samples generation, fault feature extractionand analysis. A new approach of fault samples generation considering the failurerate parameter of device and the effects of environment is proposed based on thetime simulation. In order to overcome the shortcoming of missing message betweenfault simulation data in two-dimensional correlation matrix, three-dimensionalcorrelation matrix is proposed to caculate testability index.Thirdly, study up on the modelica language characteristics, analyzes it’smodeling mechanism, extend the modelica language, enable it to bulid the testability virtual verification model and develop the library of testability virtual verification.Develop the testability virtual verification software, complete design and developingof each component of the testability virtual verification software.Fourthly, use the software to do testability virtual verification to a programmedcontrol system, compare the results between testability virtual verification andtestability physical verification, verify the accuracy and practicality of the software.