Constant Tension Control Of Ship Anchor Line Based On Marine Disturbance

With the construction of the new ship and the development of marine resources,in recent years,the state increases emphasis on the development of anchoring mechanical.Due to the impact of storms and other marine flow disturbances,the ship of anchoring state occurs swing shaking phenomenon,thus,will inevitably lead to the forces changes on each chain.Because of the large inertia of the ship at anchor,anchor chain tension appears a substantial shock and volatility with swing onboard.The relative stability of chain tension is poor,which may cause the mooring system failure and then lead to accidents.To avoid the above phenomenon,it is necessary to study the control of anchor of constant tension.In the growing age of centralized control and automation requirements,for engineering work ship,the control of constant tension has become an essential performance to most convert platform and large cargo ships mooring winches.In this paper,using boat of two anchor mooring as the research object,on the basis of separation type(MMG)structural model,according low speeds and large drift angle polynomial model of Fangcun Yasuo,three DOF mathematical model of double anchor mooring boat horizontal swaying,vertical swing and shake bow was established.By using MATLAB / SIMULINK simulation,in the setting ocean disturbance,changes in the chain's tension and athletic stance of anchored boat was acquired.With electric control windlass system as the core,AC speed regulating System of three-phase asynchronous motor was studied.Based on the analysis of three-phase induction motor vector transformation control principle,the mathematical model of induction motor in the two-phase rotating coordinate system was deduced.Vector control model of high-power motor by rotor flux oriented was established.In the MATLAB / SIMULINK software platform,motor model that can achieve stepless frequency control was obtained.Based on the above,constant torque control of the motor output shaft was studied in order to achieve the purpose of the chain of constant tension control.Finally,combined with the constant tension control requirements,it's required to dynamically adjust the retractable chain according to the forces on the anchor chain to achieve constant tension control of boat anchored chain cable at a certain disturbance of marine.And use simulation to verify the strategy validity of the constant tension windlass frequency control.In order to avoid chain retractable operation frequently,the constant tension is set at a certain range,so kept the ship's anchor chain tension within a certain range,thus caneffectively prevent the collapse of cable accident and also effectively inhibits the anchored ship Periodic yawing.The purpose of reducing labor intensity and improve the safety mooring reliability was reached.