Research On Synchronization Motion Control Of Multiple Dynamic Positioning Vessels

Consider human beings more exploring the ocean resource,the dynamic positioning(DP)technology develops rapidly.However,consider the limit capability and range of one signal vessel.By contrast,multiple vessels work together can not only improve the efficiency,but also achieve some distinguishing tasks,such as,in underway replenishment,coastguard vessel,icebreaker convoy.The study of multiple vessels control has turned into the hotspot of vessel control field,and the synchronization control of multiple vessels as one ramus of the multiple vessels control,has been attracted great attention.The research object of this paper is multiple dynamic positioning vessels.In view of the communication problem of multiple vessels carrying out tasks together,for the limit sense area of sensor,how can the multiple vessels achieve synchronization movement.When operation on the sea,the time-variant environment disturbance becomes difficulty for synchronization control of multiple vessels,how can the vessels resist time-variant environment disturbance and achieve synchronization movement to insure the security.When the communication network of vessels is unreliable,in order to keep synchronization movement of multiple vessels,time delay is introduced,when consider time delay,how can the vessels achieve delayed synchronization movement.Furthermore,when the tasks change from one to another,how can we insure the security of different task changing.Those problems are the difficulties of the study about synchronization of vessels,as well as the main idea of this paper.And this paper researches the synchronization control of multiple vessels.The following aspects for synchronization movement of multiple vessels are completed in the thesis.Firstly,the relative basic knowledge about graph theory,stability and passive control theory are described.For establishing the model of vessel,two reference frames are given,and the relative theory about Euler-Lagrange system is present.With the basic form of Euler-Lagrange,and via the kinematics and mechanics,the three degree freedom mathematical model of DP is established.Last,simulations have been used to verify direct and steady rotation,which demonstrates the effectiveness of the established vessel mode.Second,in view of the unusual communication situation,because of the environment or the limit of communication area,some vessels can receive the information from others,but can not send out information.For this situation,using the strongly connected graph,thecommunication topology is established,and the topology may be not bilateral and balance.A synchronization controller is designed,which achieve synchronization movement of multiple vessels.Then,the unknown environmental disturbance is taken into account,including the2nd-order wave-induced disturbance,ocean current and wind forces,it is assumed that measurement noise and 1st-order wave disturbance are properly filtered.And a disturbance observer is designed to estimate the time-variant disturbance online.For achieving a good result,coupling synchronization idea is introduced,which is achieved by introducing cross-coupling errors into synchronization controller.Then a global uniform bound robust synchronization control strategy is put forward,the stability of the system is analyzed,and the simulations about this control methodology are carried out.Afterwards,consider the time delay among the communication network among multiple vessels,a delayed synchronization robust controller is designed.And the stability and the effectiveness of the controller are analyzed,which demonstrates the robustness of the controller to the constant delay.Moreover,in view of in the process of caring out task of multiple vessels synchronously,it should insure the switching of different tasks safely.By the idea of guidance-control,with adaptive backstepping sliding mode control approach,an adaptive synchronization controller with guidance-system is designed.The guidance-system is realized by passive control theory and the concept of virtual leader,and the adaptive synchronization controller is deducted by backstepping and sliding mode control,which can compensate the slowly time-varying disturbance by introducing an adaptive item.The stability of the controller is analyzed,and simulations are carried out to validate this control approach.Last,the results of this thesis are summarized,and analysis of the inadequacies of the paper and expectation is given.