Research On Predictive Control And3D Simulation Platform For Dynamic Positioning System Of Ships

The increase of world’s population and the rapid development of the economy lead to large consumption of land resources. As a result, the problem of energy shortages has become very serious in today’s world. Therefore, developing and utilizing the rich marine resources are more and more important and of practical significance. With the human beings continuing to explore the deep sea, the traditional anchor mooring positioning system can not meet the requirements of vessel positioning operation. Thus, this is the reason that the vessel dynamic positioning systems were introduced. In the late70s, a new control algorithm appeared in the field of industrial process, which is predictive control algorithm. The rapid development of predictive control algorithm provides a new method for the design of dynamic positioning controller.The ship dynamic positioning system is a closed-loop control system of multiple input and multiple output. The dynamic positioning ship is affected by uncertain disturbances from the marine environment, and the accurate ship motion mathematical model is hard to be established. The model predictive control does not need high accuracy of the model and has advantages of fast response and good robustness. Firstly, this paper derives the ship mathematical model of three-degree-of-freedom and establishes the marine disturbance model. Secondly, considering unknown marine environment disturbance and small changes in the angle of dynamic positioning ship, this paper applies the dynamic matrix predictive control algorithm to the design of ship dynamic positioning controller. Furthermore, for the problem of dynamic positioning ship yawing angle change in any big case, this paper introduces self-correction technology and allocates generalized predictive control to design dynamic positioning controller. with a supply vessel for example, the above controller is simulated, and the simulation results show the effectiveness of the proposed control scheme.Finally,3D models of dynamic positioning and drifting platform are created by Creator software and Vega software is used for constructing virtual marine environment. The3D simulation platform of dynamic positioning is realized with the hybrid programming technology of VC and Matlab. The ship dynamic positioning controller based on generalizied predictive control is performed on the platform.