Reliability and Sensitivity Evaluation of an AUV through Fault Tree Model with Uncertainty Consideration

The occurrence of faults, and consequently the loss of Autonomous Underwater Vehicles (AUV) may create catastrophic outcomes to their owners. Identification of these faults and their classification provide useful information result in the detection of system bottlenecks in the design process. This paper examines the basic faults of AUVs, and studies the failure probability of their components and subsystems. The paper is then builds up the fault tree model of the AUV from its identified faults and structural Topology to highlight its critical paths, critical sub-systems, components importance, and cut-set importance values. The reliability of the AUV is then calculated from its fault tree model in the absence/presence of uncertainty associated with the failure probability of basic events. Fuzzy approach is used for handling the uncertainties. The sensitivity of the vehicle failure to the variation of the failure probability of system components is also calculated by using an innovative way. By the aid of the results of paper, the AUV reliability can be assessed at any arbitrary time frame, the appropriate preventive and predictive maintenance time be determined and by recognition of the AUV failure path, make the system more fault tolerant.