Research On Active Wave Compensation Algorithms For Marine Cranes Based On Generalized Predictive Control

With the exploitation of marine resources and the development of ocean research striding forward deep sea,besides the influence of external environmental factors such as wind,wave and current on offshore operation,the influence of operation system itself is becoming more and more obvious,which puts forward higher and stricter requirements for wave compensation technology.Based on the research of key technologies of wave compensation system of marine crane in laboratory,this paper mainly analyses the influence of cable flexibility on offshore operation and wave compensation,and researched corresponding optimal control strategies-Generalized Predictive Control-to offset adverse effects and ensure compensation efficiency.The research contents of this paper mainly include the following four aspects:(1)Modeling and analysis of active wave compensation system for marine crane.Modeling is the first step in the study of wave compensation system.On the basis of determining the overall scheme of the system,this paper mainly focuses on the mathematical models of cable,random wave and active wave compensation system test-bed,focusing on the analysis of the effect of cable flexibility on wave compensation during offshore operation.The characteristics of each part of the system are analyzed through modeling,which lays a foundation for future research work.(2)Research on generalized predictive control algorithm for active wave compensation of marine crane.Active wave compensation system itself has the characteristics of large load,large inertia and non-linearity.Considering the influence of cable flexibility,the system has serious time delay,so the existing predictive control algorithm’s effect is not good.The generalized predictive control(GPC)algorithm is very suitable for the wave compensation system because of its own predictive model,dynamic optimization and feedback correction.By explaining the basic principle of the control algorithm,the GPC controller of the active wave compensation system is established to ensure the compensation efficiency by using the predictive control theory to process the system model.(3)Simulation analysis of active wave compensation algorithms for marine crane.Combining the simulation model of the system and the specific generalized predictive control algorithm,the simulation experiment is carried out on the software platform of MATLAB/Simulink.Through the comparative analysis of the simulation results,the influence of cable flexibility on offshore operation and the effect of active wave compensation and the optimization effect of the model predictive control strategy are judged.(4)Experimental verification of active wave compensation algorithms for marine crane.On the basis of the existing test-bed,the ship motion based on spectrum is realized in the test-bed,which makes the motion of the ship simulation platform more realistic.The different flexibility of the cable is simulated by adding different springs in the middle of the wire rope,and different control strategies are used to carry out comparative experiments.The influence of the flexibility of the cable on ocean operation and wave compensation is further judged and verified by comparison.And compare and verify the effectiveness of model predictive algorithm.