Research on mathematical model and dynamic positioning control algorithm of six degrees of freedom maneuvering in marine ships

摘要

In this paper, based on the idea of separation modelling, through the analysis of ship motion and force, a mathematical model of ship motion under the action of external wind, waves and current is established in 6 free direction modelling. According to the force analysis of the ship, the calculation model of the 6-degree-of-freedom nude hull hydrodynamics and torque, the 6-DOF fluid dynamics and torque, the 6-DOF external force interference force and the moment, and the thrust and thrust of the pod propeller are established. Computing model. Finally, the computer simulation is carried out, and the fourth-order Runge-Kutta algorithm of numerical analysis method is used to calculate the 6-degree-of-freedom motion state of the ship. Through the experimental analysis and comparison with the related 6-degree-of-freedom literature, the 6-degree-of-freedom mathematical model designed in this paper is basically fulfil requirements. At the same time, according to the characteristics of ship dynamic positioning, the hybrid intelligent control strategy is used to design an adaptive dynamic positioning controller based on hybrid intelligent control. By testing and analysing the designed dynamic positioning controller, the results show that it responds in time and rises. The time is basically within the controllable range, has a certain ability to resist external environment, has good robustness, and the overshoot rate is relatively low, and the control quality is also good.