Filtered Backstepping-Based Robust Trajectory Tracking Control of Marine Surface Vessels Under Mismatched Disturbances With Fixed-Time Disturbance Observers

This article solves a robust trajectory tracking control problem for marine surface vessels (MSVs) under mismatched disturbances. First, fixed-time disturbance observers (FXDOs) with fewer parameters are designed to estimate matched and mismatched disturbances, which not only reduces the number of parameters and avoids selecting complex parameters, but also enhances the robustness of the system. Then, a robust filtered backstepping trajectory tracking control scheme for an MSV under mismatched disturbances is proposed based on the FXDOs, backstepping control, dynamic surface control technique, and a filtered error compensation dynamic method. Moreover, a rigorous proof is initially presented on the filtered error compensation dynamic method improving the convergent behaviors of the actual tracking error signals. Finally, a simulation example of an MSV is shown to verify the effectiveness of the proposed scheme.