A robust adaptive controller for underactuated ASVs in loose path-following with an added error and a new control handpoint

Controlling an ASV to follow a desired trajectory poses a significant challenge due to the unstable structure of its operating environment, which is often affected by disturbances such as wind, ocean waves, and currents. Furthermore, the ASV's dynamic model is typically highly nonlinear and contains many uncertainties. In this work, we develop an adaptive controller for an underactuated ASV to address the path-following problem under uncertain disturbances. To deal with the underactuation, a small error is added to the tracking error, and a new control hand-point technique is applied. The guidance and force adaptive control laws are designed, and their stability is proven using Lyapunov theory. In addition to the theory, Simulations in the MATLAB-Simulink environment are conducted and compared with other methods. Simulation results demonstrate the robustness of the proposed controller under unknown disturbances.