Research On Track Control Method Of Dynamic Positioning Cable Laying Vessel Based On Sliding Mode Control

With the rapid development of submarine cable communication technology,there is an increasing demand in the world for the cable laying vessel.The cable laying ship is a large necessary equipment for submarine cable laying operation and its main task is to complete the laying operation,maintaining,salvaging,routing,surveying,loading and transporting the submarine cables along the desired laying path.At present,most of the cable laying vessels are equipped with dynamic positioning(DP)system,which has the advantages of convenient operation,flexible and so on,effectively improving the handling performance of the cable laying vessels.In this paper,a dynamic positioning ship is taken as cable-laying ship and the cable-laying system component and function are introduced respectively.Then based on the low-speed characteristics of the cable laying vessel,its low-frequency mathematical model is established respectively from two perspectives of kinematics and dynamics.Finally,the simulation program of the ship model is prepared according to the motion model of the dynamic positioning cable ship,and the good maneuvering performance of the model is verified.The mathematic model of the plough's friction force and towline's movement in the cable laying system is emphatically analyzed and established firstly in the research of plough and towline in the system of cable laying.Then,it is verified that the two model meet the actual requirements through the simulation analysis.In order to research the interaction between towline movement and cable laying ship movement,the coupled model of the two motions is established.In the research of the tracking control strategy for cable laying vessel,the mathematical relationship between the desired track of the cable laying vessel and the plough's location site is determined based on the catenary equation of the towline.Then,two tracking control strategies of integrated tracking control and separate tracking control are discussed respectively.After analyzing their respective advantages and disadvantages,the integrated tracking control method is finally selected for the cable laying vessel's track control.In the design of the controller for the dynamic positioning cable laying vessel,the sliding mode variable structure control method is used to path-following control to cable laying vessel,and the accuracy of the designed controller is relatively high by simulation.For uncertain disturbances and chattering phenomena in sliding mode control,the uncertainties can be estimated by the actual parameterization firstly,then the adaptive control method is used to find the adaptive law of the parameter,and finally the adaptive sliding mode track controller is designed.The simulation shows that the control method can improve the control performance to track of cable laying vessel.