Sliding-mode Dynamic Surface Adaptive Path-following of Unmanned Vessels with Dynamic Uncertainties and Disturbances

A novel line-of-sight (LOS) based sliding-mode dynamic surface adaptive (SDSA) scheme is presented for the path-following of unmanned surface vessels (USVs) with uncertain parameters and constant disturbances. The inertia and damping matrixes of the USV are maintaining asymmetry such that it remains higher accuracy of model. Introducing the coordinate transformation to system matrixes so that turned it into skew-symmetrical form. One separates the guidance-control design procedure into two stages, guidance subsystem and control subsystem, respectively. At the first stage, considering improved LOS algorithm to ensure USV effectively sufficient following the predefined path, with the approximately calculated method of sideslip. At the second stage, using the velocity dynamics to design the surge force and yaw moment. Sliding-mode dynamic surface and adaptive techniques are adopted to compensate for uncertain parameters and constant bias caused by environmental disturbances. In particularly, the dynamic surface overcome the explosion of complexity. It is shown that the close-loop system is uniformly asymptotically stable by using Lyapunov stability and cascade stability theories. Simulation results illustrate the effectiveness and robustness of the proposed scheme by a full-scale tanker and a small vessel model with the same controller parameters.