Active disturbance rejection-based sliding mode control for a surface vessel

Active disturbance rejection-based sliding mode control is proposed for the surface vessel with exogeneous disturbances to track desired trajectory robustly. A sliding surface based extended state observer is presented to estimate the lumped disturbances and compensate them in a feedforward form. To enhance the disturbances estimation speed and accuracy, a composite adaptive extended state observer, which is adjusted by tracking error and sliding surface estimation error, is proposed to estimate disturbances. The composite adaptive estimation based tracking control is constructed in feedforward-feedback composite control strategy. The effectiveness of the designed controllers is illustrated by theoretical analysis and simulations results.