Nonlinear controller based ADRC for dynamic positioned vessels

Dynamic positioning (DP) systems for vessels are suffered from the environmental disturbances during its position keeping and offshore operation process. Because of the strong nonlinearity and uncertainty, there exist some difficulties in the design of DP controller. This paper proposes a nonlinear controller based on the active disturbance rejection control (ADRC) technique. The controller uses a nonlinear state estimator to give an estimation of the general disturbance, and then it applies the nonlinear feedback to compensate the disturbance. All these make the controller to be Anti-disturbance and robustness. The simulation results indicate the controller's validity.