Dynamic Tracking of Ship Course with Limited Input Based on ZG Control and Bivariate S-Function

The nonlinear control system of ship is complex, which is a focus of research and key core of dynamic tracking. Because the input of the actual system is often restricted by the physical constraints of the actuator and energy-saving control, the feasible region of the control input is often constrained by these factors. Therefore, by combining Zhang-gradient (ZG) dynamics with S-function, in this paper, a novel controller for the limited input system is designed. Considering the fact that dynamic systems are generally nonlinear in practical applications, the nonlinear system study has more practical significance. Therefore, this paper extends the ZG control method based on gradient dynamics and the bivariate S-function to the tracking control of nonlinear ship system, and designs a ship course tracking controller with a limited input, which can control the rudder angle within a certain feasible region while successfully tracking the ship course.