Dynamic Model And Anti-swing Control Of Heavy Lift Ship Hoisting Operation

Marine crane is the core hoisting equipment of heavy lifting vessel.It can be divided into rope luffing type and hydraulic cylinder luffing type according to the different luffing mechanism.At present,most of the cranes equipped with heavy lifting vessels are rope luffing cranes,also known as slewing cantilever cranes.This kind of crane has a wide range of applications in port construction,ship manufacturing,bridge construction,underwater robot deployment and other fields.The crane equipped with the heavy crane ship is usually operated by people,and can complete the task when there is no wind wave or the wind wave is small.However,once the significant wave height increases,or the sea condition exceeds three levels,under the guidance of the wave,the movement of the hull begins to produce violent shaking,and the swing amplitude of the lifting objects in the air increases,which brings great risk to the lifting operation.At this time,the lifting operation is generally stopped.In order to evaluate the window period of offshore installation operation in complex sea conditions more accurately,extend the application scope of heavy lift ship crane in high sea conditions.It is necessary to build a dynamic model of the crane and design an anti sway controller to restrain the swing of the crane.Therefore,it is of great theoretical and practical significance to study the anti sway control of the crane when it is working.This paper mainly studie's the dynamic response of load,the dynamic response of crane lifting system under the interference of wind and wave,and the design of load anti sway controller in the process of multi command operation.In addition,this paper establishes the two-dimensional plane dynamic model of double crane by Lagrange multiplier method to solve the problem that it is difficult to model the operation of double crane.The main research work is summarized as follows:(1)The establishment of crane dynamic model:using conservative and non conservative Lagrangian equations,the dynamic model under crane control excitation and the dynamic model of crane lifting system under coordinate point excitation are established.(2)Based on Newton's second law,the tension model of crane sling is established,and the simulation test of marine crane under multi command operation is carried out.The variation law of sling tension during crane operation is obtained,which provides theoretical basis for engineering practice evaluation and crane anti swing controller design(3)Through the numerical simulation,the crane is simulated in the four,five and six stages of sea conditions,and the amplitude of the inner and outer angle of the surface,the tension of the rope and the law of the load trajectory of the marine crane in the mooring state are obtained,which provides useful strategies and suggestions for the heavy lifting operation of the ship.(4)Dynamic model of double crane joint operation:the Lagrange multiplier method is applied to the model of double crane joint operation innovatively.The two-dimensional plane dynamic model of double crane is established,and the load swing angle and displacement in the process of double crane joint operation are analyzed.(5)Design of anti swing controller:according to the simulation characteristics of the established crane control and excitation model,the L-S joint feedback controller(sliding and luffing feedback)is designed through the joint control of slewing mechanism and luffing mechanism Controller,where 1 represents luffing and s represents slewing),and the numerical simulation shows that the control method has better convergence than the previous method which depends on the control of the rotary mechanism.