Research On The Reliability For AUV Based On Fault Tree

Autonomous Underwater Vehicle is a new generation of Underwater Vehicle, will be an important tool to complete variety of underwater mission. For example laying pipeline, inspecting seabed, collecting data, drilling support, constructing seabed, maintenance and repairing underwater equipment, maritime reconnaissance and search, underwater search and survey, communication and navigation aid, and anti-submarine action etc. In order to evaluate the system scientifically, combining the AUV system research with reliability becomes extremely urgent.After the study signicance and main content of the subject is simply introduced, reliability analysis of AUV system, system simulation of fault tree and fuzzy reliability analysis are researched in this paper.Firstly, the reliability analysis of AUV system adopts three methods basic reliability analysis, mission reliability analysis and fault tree reliability analysis. The calculation of system reliability analysis parameters of series parallel reliability model (system reliability, system failure rate, average failure time system can reach first time) are gived in this paper.Secondly, through widely collecting various failure data from service condition of AUV's each part, as well as system analysis, a system diagram of AUV is drawed, and the AUV's fault tree is constructed. According to mathematics descripting the fault tree and establishing mathematical model, system fault tree's structure function is obtained. Reliable digital simulation is made by taking this function as logic relation. AUV system's mean lifetime, the reliability distribution curve and the probability importance degree and the mode importance degree of each parts can be obtained from the simulation result. It is obvious that the importance of each parts is the same, also indicates that in the AUV system one breakdown of each parts will cause the system failure; Simultaneously, according to the mode importance degree of each parts system's weak link also can be judged.Finally, it was carried on quantitative and qualitative fuzzy analysis to AUV with the combination of the fuzzy mathematics and fault tree analysis. In the quantitative analysis, the method of step-by-step calculation on the the original fault tree and the calculation method of the equivalent fault tree were used respectively to obtain the occurrence probability and range of the top events of the AUV's fault tree. Subsequently, the fuzzy probability subordination curves were drawn in the paper.