Research On Active Heave Compensation And Anti-Sway Control System For Offshore Lifting Operation

With resources running out on land,countries have begun to attach importance to the development of marine resources,especially the deep ocean.Offshore lifting is the most common operation in the process of deep-sea resource development,which can improve efficiency of deep-sea operations.However,violent swing and heave motion of the lifting load could be produced under harsh working environment of the deep sea,which greatly threatens the safety of offshore lifting.The heave motion and swing of the load can be reduced by active heave compensation and anti-sway system effectively,thereby ensuring the safety of offshore lifting operations,increasing the window period of offshore lifting operations,and improving the efficiency of offshore resource development.On the other hand,the research on offshore lifting heave compensation and anti-sway technology is in line with the national energy strategy deployment,which can enhance the independent innovation capability of deep-sea energy mining,and make China enter the ranks of deep-sea energy mining technology power.In this thesis,related design and numerical simulation work is carried out,and the active heave compensation system and anti-sway system control method are established.The main aspect studied is as follows:(1)The research background and significance of active heave compensation system and anti-sway system are explained.The research status of active heave compensation system and anti-sway system control technology are summarized.The research goals of the thesis and the key to be solved questions and main research content are determined.(2)The working principle of the active heave compensation system and the anti-sway system are described.A three-degree-of-freedom manipulator to simulate a knuckle boom marine crane is carried out,and the kinematics forward and inverse of manipulator are analyzed.The systematic coordinate is built.The load three-dimensional dynamic model of the anti-sway system and the mathematical model of the active heave compensation hydraulic secondary adjustment drive system are established.(3)The time lag mechanism of the active heave compensation system is analyzed and a case study is conducted.The advantages and disadvantages of dynamic matrix control are studied.The traditional dynamic matrix control algorithm is improved using fuzzy PID control and form a predictive fuzzy PID controller.The predictive fuzzy PID control algorithm is compared with the traditional dynamic matrix PID control algorithm.The results show that the anti-interference performance of the system is further improved by the predictive fuzzy PID control algorithm in case of considering the system time delay.The extremely short-term motion prediction method based on the time series method is adopted to predict the heave motion of the lifting point and effectiveness of the extremely short-term motion prediction to the active heave compensation system is verified by using numerical simulation technology.(4)The anti-sway control system is designed with modern control theory.The linear quadratic optimal control is adopted to improve the traditional way of manually placing the poles,improving the efficiency of pole placement.In order to enhance the anti-jamming ability of the anti-rolling system and make the steady-state error gone,the integral state is introduced and combined with the linear quadratic optimal controller,which designs an integral quadratic optimal control anti-sway controller.(5)Numerical simulation technology is used to verify the effectiveness of the proposed active heave compensation system predictive fuzzy PID controller,time series method extremely short-term motion prediction and integral quadratic optimal control anti-sway controller indifferent sea states.The coupling relationship between load heave motion and swing during offshore hoisting is analyzed.The numerical analysis shows that when the swing angle is large,the active heave compensation system is affected greatly by the swing of the load.The swing angle can be restrained within a small angle by the anti-swing system,which can greatly reduce the influence of load swing on the active heave compensation system.