Research On Control Of Offshore Engineering Ship Anti-rolling And Anti-heeling Integrated System With Multiple Tanks

With the development of marine engineering equipment,marine operations are gradually developing into the deep and open sea,and higher requirements are put forward on the integrated balance of important offshore engineering equipment such as offshore engineering ship.Offshore engineering ship disturbed by sea wave rolls during high-risk operations such as offshore hoisting,replenishment and berthing.The sea wave causes the ship to be unable to operate at sea,and in severe cases,it may even cause the ship to capsize.At the same time,the ship heel motion due to the operation process will also aggravate the risk of deep-sea operations.In view of the problems that offshore engineering ship is disturbed by the roll and heel motion during the operation,in order to meet the needs of integrated balance of offshore engineering ship,this thesis takes Normand Pacific as the simulation object,and focuses on control of offshore engineering ship anti-rolling and anti-heeling integrated system with multiple tanks.The main research contents include the following several aspects:First,based on the spectral density theory of long-peak random waves,a mathematical model of the amplitude and moment of the long-peak random waves is established.Based on the principle of center of gravity movement,heel motion mathematical models including loading goods,unloading goods and crane rotation with goods are established respectively.Based on Conolly linear theory and U-type anti-rolling tank theory,a mathematical model of the anti-rolling and anti-heeling integrated system with multiple tanks is established.Then,in view of different working conditions of offshore engineering ships such as sailing on the sea,working at the port and getting on offshore operations,the focus is on the control strategy of offshore engineering ship anti-rolling and anti-heeling integrated system with multiple tanks.(1)For the working condition of sailing on the sea,only anti-rolling tanks work.The passive PD control strategy is adopted to control the tank valve of double-tank stabilizers,so that the double-tank stabilizers have a better anti-rolling effect on different sea conditions.(2)For the working condition of working at the port,Only anti-heeling tanks work.Based on the theory of Active Disturbance Rejection Control,an Active Disturbance Rejection Controller for anti-heeling tank is designed.Aiming at the problems of slow convergence speed and excessive overshoot in the system,an Active Disturbance Rejection Controller based on variable inclination of preset Phase-plane trajectory was designed.The control method changes the inclination of the preset Phase-plane trajectory in real time by establishing a self-adjustment rule of the response to the system phase plane and the inclination of the preset Phase-plane trajectory,and then calculates the desired movement direction of Phase-plane trajectory according to the actual position of the phase variable in the phase plane and the preset phase trajectory so as to realize the tracking of the preset phase trajectory,thereby improving the dynamic performance of the control system.(3)For the working condition of getting on offshore operations,double-tank stabilizers and anti-heeling tank work together.The total ship’s angle is filtered by designing a cascade filter composed of Kalman filter and Butterworth filter so as to separate the heel angle component and the roll angle component from the total ship’s angle,which are respectively fed back to the anti-rolling and anti-rolling subsystems.The anti-rolling tank controller and the anti-heeling tank controller work at the same time in order to realize the combination control of anti-rolling and anti-heeling.The combined system has a good control effect on the rolling of the ship in various sea conditions,ensuring that the offshore ship can still perform sea operations when the sea conditions are poor,and it can also well compensate for the heel angle generated during the operation.The system improves the working efficiency and safety of ships.The thesis designs the controller for different working conditions,and conducts simulation research on ship anti-rolling,anti-heeling and integrated control under different sea conditions.The results show that the integrated control system has better robustness and adaptability.Especially the working condition of getting on offshore operations,it can not only effectively reduce the rolling motion,but also compensate for the heel,which significantly improves the integrated balance ability of the offshore engineering ship.