| Ship is an important carrier of maritime transportation,and its safety and economy are significantly affected by motion control.Therefore,ship motion control has attracted much attention and is one of the research hotspots in this field.Ship course control is not only the basis of ship motion control,but also a very important link.The change of ship course is affected by many factors,including ship type,size and loading status,as well as external environmental factors such as wind,wave and current.The problems of noise,error and instrument failure in state measurement will affect the accurate acquisition of ship state information,which brings great challenges to ship heading control.Therefore,the research on ship course control design has important theoretical significance and practical application value.For the ship course control system,under the framework of adaptive backstepping recursive control and based on the finite time Lyapunov stability theory,this thesis studies the design of adaptive fuzzy ship course control based on observer,and solves the theoretical problems of unmeasurable state,control input constraint and error constraint in ship course control.The main contents of this thesis are as follows:1)For the ship course control system whose partial state is not measurable and with unknown system model,considering the problem of error convergence and timeliness,the adaptive fuzzy output feedback finite time control method of ship course based on state observer is studied.(1)Using the obstacle Lyapunov function and backstepping method,the barrier auxiliary signal is designed,and a ship course adaptive fuzzy output feedback control algorithm is proposed.The control algorithm can ensure that the ship course tracking error is limited to a certain range.(2)A finite time fuzzy adaptive ship heading error state limited control algorithm based on observer is proposed by using barrier Lyapunov function.Based on Lyapunov theory and finite time stability theory,the proposed control algorithm can ensure that the ship course converges to a constraint boundary in finite time,and all signals in the system are semi global real finite time stable.2)Aiming at the unknown partial state,unknown system model and the convergence timeliness of tracking error,considering the limited control input,the ship heading adaptive fuzzy control and finite time adaptive fuzzy control considering input saturation are studied respectively.(1)Firstly,the fuzzy logic system is used to estimate the unknown nonlinear function in the ship model,and the fuzzy state observer is designed to estimate the unknown heading angular velocity;Secondly,by introducing auxiliary signal processing input saturation,the physical constraint problem of bounded actuator output(i.e.control input)is solved;Finally,a ship course adaptive fuzzy output feedback control algorithm based on backstepping method is proposed.The control algorithm can ensure that all signals in the closed-loop system are semi global and ultimately uniformly bounded.(2)Based on the above research,aiming at the problem of slow convergence of ship course control system,an adaptive fuzzy ship course output feedback finite time control algorithm is proposed.Based on Lyapunov stability theory and finite time stability theory,a finite time ship course controller is designed to make the ship course tracking error converge to a certain range in finite time,and it is proved that all signals in the closed-loop system are bounded in finite time.3)Aiming at the problems of unknown partial state and unknown system model,convergence timeliness of tracking error and limited control input,considering the performance limitation,the ship heading adaptive fuzzy output feedback control algorithm and finite time adaptive fuzzy output feedback control algorithm based on specified performance are studied respectively.(1)An adaptive fuzzy specified performance ship heading control algorithm is proposed by using the specified performance technology and adaptive backstepping recursive control technology.The proposed control algorithm can ensure the accurate tracking of the desired trajectory,and improve the steady-state response and transient performance of the system.(2)A finite time fuzzy adaptive ship course controller with specified performance is designed by using specified performance technology.Based on Lyapunov theory and finite time stability theory,the proposed control algorithm can ensure that the ship course tracking error converges to a specified performance boundary in finite time.4)In view of the ship course control design algorithm proposed above,this thesis takes Dalian Maritime University practice ship Yu Kun as an example,conducting the ship course simulation research through MATLAB software,and further verifies the effectiveness of the proposed control algorithm. |
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