Fuzzy Comprehensive Evaluation About The Maneuverability Of Autonomous Underwater Vehicle

Maneuverability is critical to the security of the autonomous underwater vehicles(AUVs) and the accuracy of the scheduled tasks. Evaluation of the maneuverability ofAUVs has been attracting considerable attentions. Relationship of the indicators (i.e.hydrodynamic coefficients) used to evaluate maneuverability of the AUVs arecomplicated and difficult to be quantified. Only using a few indicators to evaluate themaneuverability of the AUVs is limited. In this thesis, in order to solve thecomplicated interdependence among the evaluating indicators, fuzzy theory wasintroduced to the evaluating system of the maneuverability of AUVs. Research of thisthesis provides a valuable reference for designing AUVs and enriches the evaluationmethods of the maneuverability of AUVs. Achievements of the thesis are summarizedas follows:(1) The CFD (computational fluid dynamics) method, in which the dynamicmeshing was realized through UDF (User Defined Function), was applied to identifythe hydrodynamic parameters. All the indicators needed for evaluating themaneuverability of AUVs were obtained. The developed method was validated to befeasible and effective by water tests.(2) Introducing the fuzzy theory into the evaluating system of the maneuverabilityof AUVs, the fuzzy comprehensive evaluation method was proposed to evaluate themaneuverability of AUVs. This method has the ability of balancing the weight ofdifferent indicators according to the requirements of the scheduled tasks. Using theproposed method can avoid the one-sidedness of evaluation by using one or a fewindicators to assess the maneuverability.(3) Based on the landing measurement requirements of the AUV, the three-levelfuzzy comprehensive evaluating system was built to assess the maneuverability of theAUV with the capability of landing on the seafloor. This system includes a total of13indicators of the stability and the flexibility. The maneuverability of two AUVs withdifferent shape was assessed, which provided a reasonable guidance for determiningthe design scheme.