RLESO-Based Command Filtered Backstepping Tracking Control for Underactuated Hovercrafts with Disturbances and Position Error Constraints

In this paper, a reduced-order linear extended state observer (RLESO) based command filtered backstepping control method is proposed for the trajectory tracking control of underactuated hovercrafts with unknown external disturbances and position error constraints. An RLESO is designed to estimate and compensate for the unknown external disturbances, and a time-varying barrier Lyapunov function (BLF) is constructed to constrain the position tracking error, on the basis of which a tracking controller is derived by using backstepping technique. Furthermore, two second-order command filters are employed to overcome the problem of “explosion of complexity” in backstepping. The control system is rigorously proved to be stable by utilizing Lyapunov stability theory. Simulation results with comparisons are finally presented to show the effectiveness and efficiency of the proposed control method.