Reliability Analysis And Evaluation Method Research For AUV Based On Fault Tree

Autonomous Underwater Vehicle can complete varieties of underwater tasks independently,with light weight, wide range of activities, autonomous working, unmanned, safety. AUV can safely arrive in the target area, accomplish the task and return to the designated area on the premise that it must have high reliability. In order to scientifically evaluate the AUV system,not only to research the AUV system, but also to research its reliability. This paper mainly completes the reliability analysis of AUV system, reliability simulation based on fault tree,and reliability simulation and evaluation software design.Firstly, taking an example of some AUV to analyze the AUV reliability, establish the reliability block diagram, and appropriate mathematical model of reliability using the basic reliability analysis, mission reliability analysis method. In the typical series and parallel reliability model, analyze the change rule of system reliability parameters and calculation method, and put forward the measures to improve the AUV reliability, from the design point.Secondly, establish the fault tree of AUV system and corresponding structure function based on the fault tree analysis method, complete the qualitative and quantitative analysis.The qualitative analysis can obtain all minimal cut-set of AUV's fault tree,namely the cause event and its combination that AUV system does not work. The quantitative analysis can obtain the probability that AUV system does not work. Through the importance analysis of the bottom event of the fault tree, obtain the most important and the most critical components,and provide the basis for improving the system design, determining the position to need to be detected of the system, and diagnosing fault. Then research and discuss the reliability simulation of AUV system based on minimal cut-set of fault tree. From the simulation result,can obtain the AUV's MTBF(Mean Time Between Failure), reliability distribution curve,importance degree and mode importance degree of basic components, and can judge weak link of system according to the mode importance degree. It is concluded that the AUV system reliability is improved through the simulation analysis, by improving the weak link reliability.Finally, research the reliability evaluation method of AUV system, combining the test data,design the reliability evaluation algorithm that combines the Bayesian method and fault tree analysis method. Complete the reliability evaluation taking an example of AUV's typical mission. Then design the reliability simulation and evaluation software of AUV system, which makes the whole reliability analysis and evaluation work easier.