Study On The Accessibility Impact Of Anti-rolling Tank On The Offshore Wind O&M Gangway

When the service operation vessel navigates at sea,due to the interference of the complex wind and wave environment,it will cause the ship’s six degrees of freedom swing motion.Among them,the rolling,pitch,and heave motion of the vessel has the most significant impact on the ship navigation and operation and maintenance operations,while the rolling motion of the ship is the most likely to occur,with the minimum damping the maximum amplitude.The excessive rolling motion of the boat in the wind and waves will cause a series of harmful effects on offshore wind power services,such as seasickness caused by vertical acceleration,reduced work efficiency and safety,and affected gangway accessibility on board.Therefore,the service operation vessel needs to be equipped with anti-rolling devices to suppress the ship’s rolling motion.According to the offshore operation environment and operation mode of service operation vessel,by comparing the advantages and disadvantages of various ship anti-rolling devices,the U-tube anti-rolling tank is selected as the anti-rolling device to suppress the rolling motion of the hull of service operation vessel and improve the accessibility of active compensation gangway crossing on board.To ensure the safety and accessibility of ship navigation and pile leaning operation.Firstly,based on the wave spectrum analysis,the wave motion model is established.Then,the ship linear roll model is obtained through the modelling and analysis of the ship motion model.Then,the fluid motion in the anti-rolling tank is modelled and analyzed by the Euler method and Lagrange method,and the fluid in the anti-rolling tank is simulated by the VOF model.Next,the anti-rolling tank’s natural period and damping parameters are obtained according to the simulation results.Then,the ship controlled passive anti-rolling tank model is established by analyzing the influence of the gas in the tank on the liquid motion when the air valve is switched on and off.Finally,by selecting the kinematics model of ship active compensation gangway,the gangway’s forward,and inverse kinematics solutions are calculated.It lays a foundation for the subsequent simulation analysis and test of the impact of the anti-rolling tank on the gangway accessibility on board.Secondly,based on the establishment of the ship anti-rolling tank system model,the anti-rolling effect of the tank is simulated and analyzed in the wave environment with different encounter angles,different sea conditions and different speeds.The simulation results show that the anti-rolling effect of the Controllable Passive anti-rolling tank based on the prediction of ship rolling motion based on wavelet neural network is the best.To evaluate and analyze the impact of the anti-rolling tank on the gangway accessibility on board,the effect of the anti-rolling tank on the seasickness rate is simulated and analyzed.The simulation results show that the anti-rolling tank can effectively reduce the occurrence of seasickness,to improve the gangway accessibility on board.Then,according to the installation position,structural size and attributes of the gangway,the operation standards of the gangway on board are obtained,and the impact of anti-rolling tank on gangway accessibility is simulated under different meaningful wave height and wave environments.The simulation results show that the gangway accessibility onboard is significantly improved when the ship is equipped with a Controllable Passive anti-rolling tank.Finally,the semi-physical test verification of the active compensation gangway is carried out.Through the ship anti-rolling tank system designed in the simulation computer,the ship roll response is used as the control signal to the programmable logic controller to control the six-axis swing table to simulate the ship motion and the output signal of the attitude sensor on the six-axis swing table is fed back to the anti-rolling tank module in the simulation computer,As the input of active compensation gangway,it constitutes a hardware in the loop closed-loop system.The test shows that the rolling motion response of the ship is effectively restrained by the anti-rolling tank,so the accessibility of the gangway is significantly improved.