Research On Construction And Analysis Method Of Dynamic Fault Tree Based On The System Design Model

With the widely application of the embedded systems in safety critical areas such as aviation,aerospace and nuclear industries,the scale and complexity are improving.How to ensure the reliability and safety of the embedded systems has become a priority of the current academic and industrial research.On the one hand,when producing an embedded system,most of the errors are made during its design stage.Furthermore,because the system design and system analysis are separated from each other,when the system analysis is performed later,the cost of fixing each error is several times or even dozens of times the cost of correcting the errors in the early design stage of the system.On the other hand,dynamic fault tree is an effective and widely used analysis model for the reliability and security of the system,but its construction is usually completed by analysis engineers,its reliability is greatly reduced.With the increasing large scale of the system,it is more and more difficult to manually construct a dynamic fault tree.Besides,because the quantitative analysis method of the dynamic fault tree based on Markov chain is short of the effective tools to support,it has many weaknesses such as the complicated calculation process,commonly happened human errors,a lot of manpower and material resources and inaccurate calculation results.Aiming at the above problems,this paper proposes a dynamic fault tree automatic construction method based on the system design model of SysML,which Combines the system design with the system analysis by carrying out reliability analysis and system design at the same time.Based on probabilistic model detection tool of PRISM,a quantitative analysis method of dynamic fault tree is proposed.This method contributes to conducting a quantitative analysis on the dynamic fault tree efficiently and accurately.The main research contents of the thesis are as follows:(1)Based on dynamic fault tree construction method SysML activity diagram and extended SysML module definition diagram,an automatic generation method of dynamic fault tree is proposed.Firstly,based on SysML's profile extension mechanism,the SysML module definition diagram is extended with semantic extension on the error description of the module,and then combined with SysML activity diagram,an automatic construction algorithm for dynamic fault trees automatically generates a dynamic fault tree.(2)Based on probabilistic model detection tool of PRISMA,a quantitative analysis method of dynamic fault tree is proposed.The continuous-time Markov chain model is used to formalize the dynamic fault tree,and it is implemented in PRISM language.Description,generate the input model of the PRISM tool,then define the CSL attribute specification formula for quantitative analysis,and finally use the tool to perform the results of the quantitative analysis.(3)By designing and implementing prototype tool of T-CDFT2 PRISM that generates the dynamic fault tree automatic generation and converts it to the PRISM,the thesis analyzes the case of an aircraft icing detection system,and explain the feasibility and rationality of the proposed method.It provides a new idea for the reliability analysis on the safety-critical embedded systems.