Adaptive integral terminal super‐twisting with finite‐time convergence for an unmanned surface vehicle under disturbances

This article proposes a robust trajectory tracking controller for underactuated unmanned surface vehicles under disturbances. An adaptive integral terminal super‐twisting algorithm is designed for guidance and control, following a cascade strategy. The properties of such algorithm include practical finite‐time (PFT) convergence, robustness against bounded disturbances/uncertainties with unknown boundaries, and chattering attenuation via adaptive gains. A stability analysis is addressed to prove the PFT stability of the overall system. Moreover, the vehicle is subject to wind, waves, and water currents disturbance models to verify the robustness with numerical simulations. Furthermore, real‐time experiments under an extra payload and environmental perturbations with unknown boundaries validate the performance with a prototype. Finally, a comparison against the adaptive super‐twisting algorithm with conventional sliding surface further demonstrates the advantages of the proposed scheme.