Research On Heave Motion Control Of Surface Effect Ships

The 21st century is a new era of maritime navigation.With the rapid exploitation of marine resources and the increasingly prosperous ocean-going trade,all coastal countries will make efforts to promote the comprehensive strength of the oceans and improve the utilization of marine resources as an important strategic goal.The surface effect ship with high speed,good maneuverability,wave-resistance and other advantages,is widely used in widely used in civil and military fields.When the surface effect ship is used to transfer or cargo to another ship or the offshore wind farm as an operation vessel,unknown time-varying wave disturbance will easily affect the heave motion of the surface effect ship.Severe heave movement seriously affects the safety of material or personnel in the process of transfer.Therefore,it is of great theoretical value and practical significance to control the heave motion of surface effect ship for reducing the amplitude of it.Firstly,a mathematical model of heave motion of surface effect ship and a mathematical model of wave disturbance are established in this thesis.Then,considering that the heave displacement of surface effect ship can not be measured directly,an observer based on Kalman Filter is constructed to estimate heave displacement and heave velocity of surface effect ship according to the measured heave acceleration.Further,statistical analysis is made on the time series established by the estimated values of heave displacement and heave velocity.The autoregressive model is used to predict heave displacement and heave velocity.The least squares method is used to estimate the model parameters and the classical AIC criterion is used to determine the order of the autoregressive model.Further,based on model predictive control,a heave motion controller is designed to realize the heave motion control of surface effect ship.Finally,the autoregressive model is applied to predict the volume of air cushion disturbed by ocean waves.Further,a compound control strategy is proposed for the heave motion control of a surface effect ship,which promoted the accuracy of heave motion control of a surface effect ship.Simulations are carried out for a surface effect ship,and results demonstrate the effectiveness of the developed control method of the heave motion.