Simultaneous modeling and backstepping control algorithm for trajectory tracking of underactuated USV based on real-time sailing data in complex ocean conditions

The trajectory tracking problem of underactuated unmanned surface vessel (USV) in complex ocean conditions is investigated in this paper. A kind of high-precision maneuvering motion group (MMG) model is established to replace the traditional Fossen model for the trajectory tracking of underactuated USV. To improve the accuracy of identified USV model parameters, a novel multi-innovation least squares (MILS) identification algorithm is proposed by expanding the innovation value to a vector matrix, and then online identified USV model parameters are obtained by using MILS algorithm based on the real-time sailing data. Concurrently, by introducing virtual point position information and intermediate state, the proposed approach concurrently reduces computational requirements in the design process of the backstepping control algorithm. In addition, considering the effects of identification modeling errors and ocean disturbances, a nonlinear composite disturbance observer is designed, further enhancing the stability of the control algorithm. Finally, the effectiveness and reliability of the proposed algorithm are verified through simulation experiments.