Research On Vertical Motion Control To High Speed Ship Based On H₂

With advances in technology,not only the ship's design and manufacturing technology has made considerable progress,but also the speed of ships has been greatly improved,while there have been many new ships,such as catamarans,hydrofoils,boats and other surface effects.With the increasing speed,the effect of wave disturbance to the vertical movement of the ship will increase.Because of the vertical movement,especially heave,pitch voyages waves will cause great harm to the ship.So after the ship rolls issue has been resolved,the vertical movement of the ship sway become the most problems to be solved.Meanwhile the boat swaying motions will be accompanied by transverse,longitudinal acceleration swaying motion,which increases the incidence of seasickness,making passenger `s comfort greatly reduce.Because now passenger ship traffic has play an important role in Maritime transportation,so the issue which will improve passengers `comfort has been placed in the first place,and controller designed specifically for this issue has become more urgent.For these problems,this paper explore the use of integrated control system T-wing and ressure wave board to control the vertical movement of the ship.In this paper,seasick's influence on comfortable of ship riding is took into account taking into account the impact of seasickness ship ride comfort,trying to improve the comfort of the passengers on board by vertical motion control.This paper uses the theory of rigid body motion,combining damping and restoring force made by sea water when ship traveling in the sea,the six degrees of freedom model of ship is obtained.Taking into account the symmetry properties of the hull and slender,the six degrees of freedom model is divided into two parts,vertical movement and lateral movement.And according to the research purpose,the modified ship`s mathematical model is adopted,which makes ship model more accurate and determines the mathematical model of vertical movement of high-speed ship.The mathematical model of Nag amine random waves is also analyzed.Long peaks random wave simulations are established by the calculation,and long peaks random waves has also been studied.The reason of seasick is analyzed.Using mathematical models incidence of seasickness,the controller is designed by the worst vertical acceleration(WVA)of ship as an indicator system function.An system model is established through the analysis of ship control process model and executive body.Through the analysis of the traditional PID controller,the integral part has been proved it isn`t obvious to vertical movement of the ship.Therefore,multivariable PD controller is mainly used for vertical movement in this paper.H2 norm of closed-loop transfer function is used as an indicator function based on H2 control theory,and the system of state-space model has been established.The analysis revealed that the state-space model is not accurate because of ignoring the nonlinear module,so a frequency domain analysis method based on the variance function describing the gain has been proposed.It is proved that this ship control system has a high degree of nonlinearity through this method,so the non-linear characteristics can`t be ignored.Based on this conclusion,this paper presents a simulation model to directly obtain the worst system of vertical acceleration as an indicator of the number of H2 norm.Through analysis of the indicators,H2 norm has been proved it can be more accurate to show the minimum point of vertical acceleration of ship.Calculation of the controller parameters is achieved by genetic algorithm,the results of the analysis,found that the effect of the design of the controller is not ideal,so nonlinear optimization algorithm based on genetic algorithm has been used to optimize the parameters of the secondary.Through simulation of optimized controller,the conclusion show that the controller designed in this paper for the ship's heave,pitch,and the incidence of seasickness has ideal control effect.