Research On Dynamic Positioning Control Method Of A Vessel Based On Auto Disturban Rejection Controller

With the development of marine engineering, dynamic positioning system has beenwidely used on offshore platform. Due to the increasing complexity of ship operations, therequirement on dynamic positioning has also been increased. The ability of dynamicpositioning depends largely on the control methods. Thus, it is necessary to find a controlmethod which can resist interference, and does not depend on the ship precise mode.According to research, active disturbance rejection control (ADRC). Thus, this paperresearches on the control of dynamic positioning system based on ADRC.Firstly, the mathematical models of ship, wind, sea wave and sea current were built. Thethree degrees of freedom mathematical model of surface ship for dynamic positioning systemwas built, and then mathematical model of wind, sea wave and sea current in the oceanenvironment were built, and the effectiveness of the models were proved. The establishedmodels lay the foundation for the continuing prove for the effectiveness of controller.Secondly, the paper reasearches the control method of ARDC controller. At first, thestructure of ADRC controller is analyzed, and the components-the trackingdifferentiator,extended sate observer and nonlinear state feedback control law-of the ADRCcontroller are described respectively in detail. Then the effection of the noise in the outputsignal on the ESO is discussed and ESO with filter is designed. It has been tested that theimproved observer waked the influence of noise on the estimation of ESO to a large extent.Finally, this paper researched on the dynamic positioning control method based onADRC. In the background of dynamic positioning, according to the analysis on the orders ofship model and ADRC, designed the ship dynamic positioning ADRC, in which the ESO withfiltering function was used. Meanwhile, since the parameters of nonlinear feedback controllaw is difficult to set, fuzzy controller is used to set the parameter. Then proved theeffectiveness of fuzzy ADRC controller.The research work of this paper mainly focused on the control method of dynamicpositioning system, and discussed about the application of ADRC theory in dynamicpositioning system, then simulation was carried out for the designed controller in this paper.Simulation results proved the effectiveness of proposed method.