The Research Of The Motion Attitude Control Of Deep-V Ship

As an emerging special ship type,deep-V ship carries on the excellent performance from different kinds of ships,with speedility,maneuvering flexible,high response speed and so on,that deep-V ship has been used in military matters and other kinds of speed and efficient ocean transportation area.However,because of its thin and long type,in practical sailing,specially sailing in badly sea environment,it will cause instability roll which will cause serious safety problems for ship sailing as well as people and goods.Fin stabilizer is usually used to improve the ship's maneuvering characteristic.However,as the special ship type,the use of fin stabilizer may increase yaw moment,yaw angle,and even cause unsafe factor.This paper tries to design a reasonable fin/rudder controller to improve the motion attitude control of deep-V ship on the basis of non-linear motion model.The main content of this paper include:Firstly,the research results of deep-V ship moving posture control at home and abroad are systemized,and the maneuvering effect of different kind of control devices are contrasted.The 4-freedom non-linear mathematic motion equation is established and the solving method of hydrodynamic parameters is also given out,among which the mathematic models of rudder and fin are contained and their saturation limits are also considered.The environment disturbance models of wind,wave and ocean current are built.The irregular wave disturbance model can be got through the superposition of the disturbance force and moment from unit amplitude of regular wave.The disturbance model of wind can be got using empirical equation.The mathematic model of current can be got by analyzing current characteristic and exploiting the relative speed and the absolute speed.Secondly,the deep-V ship is taken as the research object.The anti-rolling effect and the effect on yaw of different installation site of fin stabilizer in different sea state are analyzed.The result show that the influence of installation site of fin stabilizer on motion attitude control to deep-V ship is much greater than to round bilge ship.Then the LQG controller is designed.It is necessary to optimize the parameters of linear part as the non-linear motion model is linearized in the process of controller design.The simulation results with optimized parameters can be got using Monte Carlo method.And then the fin/rudder controller which could improve ship's motion attitude in varies sea state is given out.Thirdly,the inaccurate linear model can be improved using LPV method.The more reasonable fin/rudder controller for deep-V ship can be got using robust variable gain programming method based on LPV.Finally,the simulations of roll and yaw for deep-V ship in different sea states(mainly meant significant wave height and encounter angle)are carried out.The simulation results of fin/rudder controller and heading controller show that the fin/rudder controller has greater anti-rolling effect and course-keeping ability in different sea state which could improve stabilizer efficiency and heading control precision to some extent.