Time domain analysis of dynamic positioning system is one of the key technologies of dynamic positioning system.Time domain analysis is a response course that simulates the position and heading of the drilling platform in time domain and the response of each propeller with position and heading.It can provide reference for practical engineering design,which is conducive to further and effective improvement.Therefore,the dynamic time domain analysis plays an important role in the design of dynamic positioning system.In this paper,the dynamic positioning system model,state estimation method and time domain simulation method are studied.Based on the time domain analysis method,the time domain analysis of dynamic positioning system is developed by using Matlab and Simulink programming.Finally,the marine drilling platform is taken as the research object and its positioning ability is analyzed.The main work of this paper is as follows:(1)A coordinate system and related mathematical models for dynamic positioning of drilling platforms are established,including platforms and environmental loads.The dynamic equations of the platform under the condition of hydrostatic and normal operation are studied.A mathematical model of low frequency and high frequency motion is established.The calculation method of the force and torque of the hydrodynamic derivative and wind wave flow environment is studied.(2)The state estimation method in the dynamic positioning system is studied,and the mathematical model of the state estimation object and the corresponding state space equation are established.In order to solve the problem of non Gauss approximation and nonlinear system,particle filter is introduced to solve the problem of non Gauss approximation and nonlinear system.Finally,in order to make up for standard particle filter,to solve the problem of non Gauss approximation and nonlinear system,the problem of non Gauss approximation and nonlinear system is solved.The improved MCMC particle filter is studied,and the simulation and analysis of the dynamic positioning state estimation are carried out based on the improved algorithm.(3)The time domain simulation system of dynamic positioning system is constructed,which includes platform module,environment load module,motion state estimation module,controller module and thrust distribution module.According to the two methods,which are the limit wind speed curve and the utilization rate curve of the propeller,the calculation method of two curves in the time domain analysis is given,and the.M file is used to call the Simulink file in the form of cyclic iterative calculation.Finally,the time domain simulation is realized for drilling leveling.(4)An example of the time domain analysis of the dynamic positioning of the drilling platform is completed.The basic data of the platform and the parameters of the propeller are introduced with the 981 drilling platform as the object.The numerical values of the hydrodynamic matrix and the mass matrix in different working conditions are given.Finally,the limit wind speed curve,thruster utilization curve and time history curve are calculated by the time domain analysis and simulation system..The simulation results are analyzed. |