The Research Of Fault Diagnosis Of The Automobile Brake System Based On Fault Tree Analysis And Fussy Theory

The FTA is the one that is more fit for the complicated system. In this thesis, combining the FTA with the fuzzy theory, the uncertainty problem that cannot be solved with the traditional FTA in the automobile fault diagnosis, the multi-fault phenomenon that faults take place in complex system and the intersectional relation between fault omens and fault reasons is solved. The basic trait and step of the FTA are introduced, and the matrix algorithm of the qualitative and quantitative analysis of fault tree are also studied. Transforming the fault tree into the fault matrix according rules, changing the tree structure into the data structure and converting the symbol processing into matrix computation can easily store the information of the fault tree in computer and efficiently improve analysising speed. In the bottom event, the concept of the basic condition in the priority of selecting the fuzzy number model is brought forward, and traits of the fuzzy number model is analyzed and compared. The reason that the accurate probability is replaced with the probability of linear fuzzy number is elucidated. Combining the Fuzzy Decision-making theory with the analysis method of the interested degree in fault tree analysis, the ideas of ensuring the membership degree with the interested degree and establishing fuzzy matrix is put forward, and is testified with the stringent mathematic theory. Therefore, the efficiency and quantity of fuzzy matrix establishment is improved, and further the field of application of fault tree analysis is developed. Based on the fault tree analysis theory, the CAFTA is manufactured. The automobile's dual atmospheric circuit brake system is simply introduced, and it's fault mode and reason, fault reasult and effect are also analyzed. Apply the manufactured CAFTA , the fault tree that is out of order in braking system is analyzed. The result is preferable.