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The lattice Boltzmann method is a new computational fluid dynamics method, which can simulate several kinds of fluid problems. In this paper, a part of hydrodynamic coefficients of an AUV with a complex shape were obtained by a numerical simulation in CFD software based on lattice Boltzmann method. The pure pitch and pure heave motion of PMM experiment were conducted in CFD software Xflow and corresponding resistance and resistance moment were measured. The Wall-Adapting Local Eddy (WALE) viscosity model was employed to stabilize the simulation. In order to obtain the corresponding hydrodynamic coefficients, Response spectrum analysis was performed on the results derived from CFD simulation. The complex work of meshing is avoided and the workload of numerical simulation is significantly reduced.

An adaptive fuzzy sliding mode controller is proposed for the depth control of an underactuated underwater vehicle based on the state-dependent Riccati equation. An adaptive fuzzy control algorithm is embedded into the sliding mode controller to solve the buffering and mismatched uncertain problems in the robust sliding mode variable structure controller, where an auxiliary fuzzy control unit is designed to automatically adjust the scale factor of the main fuzzy controller output. Based on Lyapunov stability theory and final value bounded theorem, the stability and convergence properties of the closed-loop system are demonstrated. Numerical simulations are carried out to validate the effectiveness of the proposed controller.