Trajectory Tracking And Formation Control Of Vessels With Intermittent Communication

The ocean gives birth to life and also contains abundant resources.In recent years,the society at home and abroad has intensified the exploration of the oceans,and has paid more attention to the control of naval supremacy.Under the new era background,vessels are 'given important missions,in order to execute the tasks such as transportation and escort in different environments,trajectory tracking,coordinated formation and more instructions need to be applied to vessels.However,on the actual sea surface,because of the influence such as equipment limitations and environmental interference,intermittent communication may occur during communication.At present,the related researches on intermittent communication are mostly focused on multi-agent systems.This thesis will base on the research results of multi-agent systems consensus with intermittent communication,and combines the relevant theories of vessels to solve the problems of vessels trajectory tracking,formation control and formation-containment control with intermittent communication.At the same time,considering the interference of environmental factors such as wind and waves on the sea surface,the disturbance observer is used to estimate the interference,and control laws of vessels during the normal communication period and the non-communication period are designed separately for different mission objectives.In order to ensure the ideal control effect,this thesis will give the sufficient conditions to achieve different tasks and prove them.The main research contents of this thesis are as follows:1.Research on the trajectory tracking problem of vessel with intermittent communication,it is assumed that the vessel can only obtain the ideal trajectory signal intermittently.First,the backstepping method and disturbance observer are combined to design the control law of the vessel during the normal communication period,and the vessel's own information is used to design the control law of during the non-communication period.Then the sufficient condition for trajectory tracking is given and the stability of the system is proved.Finally,it can be seen from the simulation results that when the sufficient condition is satisfied,the designed control law can achieve ideal effect.2.Research on the formation problem of multiple vessels,and it is assume that intermittent communication occurs between vessels in leaderless and leader-follower formation.First,the control law of vessels is designed based on graph theory and dynamic surface method to avoid differential expansion.Then combined with Lyapunov function,the sufficient condition for vessels formation with intermittent communication are given,and the formation stability is proved.Finally,it can be seen from the simulation results that the designed control law can realize vessels formation and limit the error within a certain range.3.Research on the formation-containment problem of multiple vessels,and it is assumed that the communication conditions of the leaders group and followers group are different.Design control laws for completely intermittent communication and partly intermittent communication respectively,and introduce the second-order filter,compared with the first-prder filter,the second-order filter can make the filtering error converge to a certain neighborhood in a limited time.Then combine with the Lyapunov function,the sufficient conditions for formation-containment control in two cases are given respectively,ensure that the vessels of followers group can converge to the convex hull surrounded by the vessels of leaders group finally,the law can realize the formation-containment control of vessels with different intermittent communication situations.