Research On Multi-AUV Circular Formation Control Based On Cyclic Pursuit Strategy

Autonomous Underwater Vehicle(AUV)has always been the focus of research as an effective tool for exploring the ocean.Compared with single AUV,multi-AUV has larger operating space and stronger operating performance,so multi-AUV formation control has attracted more and more attention from researchers.Among the many AUV formations,the circular formation has an advantage in performing target rounding up,large-scale search and other tasks.For multi-AUV circular formation control,circular formation trajectory is generated by using cyclic pursuit strategy,and AUV trajectory tracking controller is combined to realize circular formation of AUVs in this paper.The specific research content has the following aspects.First,the AUV six-degree-of-freedom kinematics and dynamics model are established,and the AUV model is simplified to the horizontal plane model.Then the horizontal trajectory tracking guidance law of AUV is designed,and the reference state variable of AUV motion is obtained by taking the expected trajectory point position information as input,thus the tracking error equation is established.Then AUV trajectory tracking controller is designed based on sliding-mode control and double-loop control structure.The stability of the control system is proved by Lyapunov stability theorem.Finally,simulations are designed to verify the feasibility and effectiveness of trajectory tracking control.Secondly,part of linear cyclic pursuit and nonlinear cyclic pursuit in the cyclic pursuit strategy are analyzed.Circular formation trajectory is generated by using the cyclic pursuit strategy,and AUV circular formation control is realized by combining with the AUV trajectory tracking controller.Simulations are designed to verify the feasibility and effectiveness of AUV circular formation control using different cyclic pursuit strategies.The characteristics of AUV circular formation based on different cyclic pursuit strategies and the deficiencies in setting the formation characteristics of circular formations are analyzed.Thirdly,an improved cyclic pursuit strategy is analyzed to clarify its advantages over other cyclic pursuit strategies for customizing the center and radius of circular formation.By adding the role of "observer" to the formation members,the circular formation trajectory generation based on the improved cyclic pursuit strategy is realized.The circular formation control is realized by combining with AUV trajectory tracking controller.Different simulation experiments are designed to verify the effectiveness of the circular formation control based on the improved cyclic pursuit strategy and the advantages and disadvantages of the formed circular formation.Based on the characteristics of the improved cyclic pursuit strategy,the formation recombination strategy when the formation members are added or removed is designed,and the simulation is designed to verify its feasibility and effectiveness.Finally,the optimal trajectory of circular formation is designed based on the Hungarian algorithm.The optimized trajectory adjusts the position and heading angle of the formation members,so that the formation members at any initial position can spend less time to achieve uniform distribution on the target circular formation.Finally,simulation is designed to verify the feasibility and effectiveness of the optimized trajectory.