The Controller Design Of Marine Dynamic Positioning System Based On Disturbance Observer

Dynamic positioning is a problem in recent years, it has been proposed and its difference from the traditional mooring positioning, is refers to the ocean of a ship or structure by its own power system, overcome the interference of, keep the movement state of the ship or structure or hovering control. With the development of marine industry,marine operations will be increasingly difficult to increase the construction, and power positioning technology in marine resources exploration, oil exploitation, transportation and other materials will play an increasingly important role. From the development of dynamic positioning technology, the control algorithm has been continuously updated to adapt to the new situation, and the nonlinear control theory in the field of dynamic positioning control is applied to the nonlinear control theory. In order to solve the influence of external disturbance and observation disturbance in the system, the disturbance observer is introduced into the closed-loop control to observe and suppress the interference. In this paper, the control system is verified by the mathematical model of the supply ship. In the process of the research, this paper analyzes the kinematics and dynamics model of the ship in the three degree of freedom system, and establishes a mathematical model based on the state space equation. When the ship is floating on the sea or on the sea, it will always be disturbed by the complicated external conditions, such as the sea and wind flow, which increases the difficulty of the system control design. Disturbance observer is introduced,which can effectively observe and estimate the disturbance of external force and moment of the ship, and introduce interference compensation in the system. Because the main disturbance is the low frequency signal, the core content of the disturbance observer is the analysis of the low pass filter in the observer, so the main emphasis of the disturbance observer is the low pass filter design. In order to realize the design of the system, the fuzzy PID control theory is added to the control system, and the response speed and control precision of the system are improved. The fuzzy PID controller based on interference observation is very good to solve the problem of system response and suppression.