Research On Heave Motion Control Of Surface Effect Ship

In recent years,with the rise of marine resource exploration,growth of marine economy,improvement of the ability of marine resource development and marine power building are established as a long-term strategic goal of our country.Surface effect ships are widely used in the exploration of marine resource due to their characteristics of high energy efficiency,shallow draft and good maneuverability.However,surface effect ships are inevitably moved in heave due to sea wave during the operation,which may affect the safety of personnel on board.In addition,surface effect ships involve uncertainty of wave disturbance,input saturation and unavailable heave position,etc.Therefore,it has theoretical significance and practical application value to carry out researches on heave motion control of surface effect ships.For the problems of surface effect ships heave motion control,the main research work is as follows:In the presence of unknown time-varying wave disturbance,the disturbance is represented as the output of a linear exosystem with all eigenvalues lying on the imaginary axis.Based on the exosystem,the disturbance is further represented as the output of a linear model of canonical form by a linear regression model.Following this representation,a state observer is designed.On the basis of heave position,heave velocity and control input of surface effect ships,the state vector of the canonical linear model is estimated.From the above,a robust adaptive control law is designed by applying adaptive backstepping control theory to reduce the heave motion amplitude of surface effect ships.Moreover,in the presence of unknown time-varying wave disturbance and input saturation,a disturbance observer is designed.According to heave position,heave velocity and control input of surface effect ships,the unknown time-varying wave disturbance is estimated.Meanwhile,an auxiliary dynamic system is introduced to handle the impact of input saturation.To summarize,a robust control law is designed by applying backstepping control theory to reduce the heave motion amplitude of surface effect ships.Finally,in the presence of unknown time-varying wave disturbance and unavailable heave position,the disturbance is represented as the output of a linear exosystem with all eigenvalues lying on the imaginary axis.In the light of the exosystem,the disturbance is represented as the output of a linear model of canonical form by a linear regression model.Following this representation,an observer is designed.On the basis of heave velocity,heave acceleration and control input of surface effect ships,the derivative of the state vector of the canonical linear model is estimated.Summing up the above,a state-derivative robust adaptive control law is designed by combining adaptive technique and Lyapunov direct method to reduce the heave motion amplitude of surface effect ships.Simulations on the Norwegian SES are carried out by using the Matlab/Simulink toolbox.The results demonstrate that the designed surface effect ships heave motion control laws reduce the heave motion amplitude of surface effect ships in different situations.