Research On The Ship's Rudder Roll Damping Control System Based On T-S Fuzzy Models

Ships sailing on the sea often roll violently.Roll can not only make passengers get seasick and reduce the efficiency of work,but also make the goods of the ship clash each other.Roll affects the ship's maneuverability,and even affects the safety of the ship.Therefore,the roll damping control has always been a hot research topic in the ship's motion control,and has the value of engineering.In this paper,the status and the existing problems of the rudder roll damping(RRD)system are analyzed.RRD system is studied based on the T-S fuzzy system.Some algorithms,such as linear matrix inequality(LMI),parallel distributed compensation(PDC),are used.Some theories,such as domain stability,H? control,adaptive theory,Lyapunov stability are applied.The research works are as follows:Firstly,in order to reduce the wear and energy consumption of the steering gear under the premise of the certain performance index or the control effect,the T-S fuzzy controller with input constraints of the RRD system is proposed.Since the nonlinear hydrodynamic coefficients in the ship motion equation change with the speed of the ship,the T-S fuzzy models of the ship's nonlinear equations can be established.And the fuzzy controller is designed by PDC principle.The input of the controller is constrained at the same time.Because the input constraints can be easily converted to LMI constraints,it is suitable for practical engineering applications.Simulation results show that in comparison with the fuzzy controller without input constraints,not only the fuzzy controller with input constraints can promote the damping and heading control effect obviously,but also the rudder angle amplitude of the controller's output is reduced obviously,that is,the wear of the steering gear and the consumption of energy are reduced.Secondly,in order to make the RRD system satisfy the given transient performance,the T-S fuzzy controller of the nonlinear ship roll system with the constraints of domain stability is designed based on the domain stability and Lyapunov stability theory.The fuzzy controller guarantees not only the stability of the RRD system,but also satisfy the given transient performance through set all the closed-loop poles of each linear subsystem of the T-S fuzzy system into a designated area on the left half complex plane.Thirdly,in order to make the the RRD system's inhibitory effect on the disturbance produced by waves,sea breeze and current meet the given performance index,the nonlinear H? fuzzy controller of the RRD system is designed.In the same sea condition,the damping effects of the pure fuzzy controller and the two kinds of nonlinear H? fuzzy controller are compared.The anti-interference ability of the two nonlinear H? fuzzy controller is superior to the pure fuzzy controller.And the H? fuzzy controller designed relatively conservatively is poorer.Fourthly,the ship's velocity and acceleration can not be directly measured sometimes.In order to solve the implementation difficulties of the system which composed by the feedback variables made by the state variables,the T-S fuzzy observer of RRD system is designed.T-S fuzzy observer is a kind of nonlinear observer.It is suitable for the ship system which include nonlinear hydrodynamic coefficients.Combined with the adaptive theory,the adaptive fuzzy observer is designed based on the T-S fuzzy model.This observer not only has the advantages of the T-S fuzzy observer,but also can estimate unmodeled dynamics of the system.Simulation results show that the adaptive fuzzy observer can estimate the uncertainty dynamic of T-S fuzzy model,make up for the imperfections of the fuzzy rules,and get better observation results.