Under-actuated ship trajectory tracking control method and system based on identification modeling

The invention discloses an under-actuated ship trajectory tracking control method and system based on identification modeling. An identification model, an improved expansion state observer and a trajectory tracking controller are designed; comprising the steps of S1, determining a three-degree-of-freedom model structure through mechanism analysis according to motion characteristics of an under-actuated ship, and identifying model parameters through ship navigation data by adopting an extended Kalman filtering algorithm to obtain an identification model; s2, using a model identification error and an environment disturbance error as total disturbance, and designing an improved expansion state observer to estimate the total disturbance of the system; s3, designing a trajectory tracking controller based on a sliding mode control theory, adopting an exponential reaching law and a linear sliding mode surface according to the ship control task complexity, and adding disturbance compensation in the design of the cont