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Three‐dimensional trajectory tracking of an underactuated AUV based on fuzzy dynamic surface control

The three-dimensional trajectory tracking of an underactuated autonomous underwater vehicle (AUV) under the complex unknowns including model uncertainties and time-varying disturbances is studied. The reference pitch angle and yaw angle are designed in kinematics, based on the time-varying reference trajectory. Dynamics controllers are developed by incorporating the first-order filter into the dynamic surface control (DSC), which simplifies the design process and overcome differential explosion in the traditional backstepping. To reduce the influence of the complex unknowns, an adaptive fuzzy-based DSC scheme is employed to identify the lumped disturbances with arbitrary accuracy and further enhance system robustness. Lyapunov stability analysis demonstrates that tracking errors are bounded and converge to an arbitrarily small neighbourhood of zero. Finally, simulation studies and comparisons with DSC scheme are carried out to illustrate the effectiveness and superiority of the proposed scheme.