Research On Multi-UUV Cooperative Method For Target Search

As the backbone of promoting the development of the marine industry,Unmanned Underwater Vehicle(UUV)has received extensive attention in both military and civilian fields.With the complexity of marine operations,single UUV has been difficult to meet the mission requirements,so the way of multi-UUV cooperative operation arises at the historic moment.This paper focuses on the multi-UUV collaborative search problems as follows:Firstly,summarized the methods of multi-UUV collaborative search,analyzed the difficulties of target search under different collaborative search methods,and propound the corresponding solutions.On this basis,the environmental grid model,UUV kinematics model,pre-sonar model and mission evaluation model are established.At the same time,the characteristics of multi-UUV communication environment are analyzed.Secondly,discussed the search efficiency of multi-UUV in different search modes in different formations,focuses on the search path planning under the multi-UUV horizontal queuing shape.Aiming at the situation that all UUV need to turn outside the search area in the traditional "Z" shape search path,an improved "Z" shape search path is proposed,which reduces the overall search path length of UUV formation on the premise of ensuring complete coverage of the area.After the formation reconstruction due to the fault,the sustainability of the search algorithm is analyzed.Simulation results show that the improved algorithm can improve the search efficiency of UUV formation.Then,analyze in detail the method of multi-UUV cooperative search target under known environment information.According to the characteristics of the problem,the problem is divided into two sub-problems: task area allocation and sub-area coverage path planning.Aiming at the problem of task area allocation,a UUV performance evaluation method based on fuzzy reasoning is proposed,and based on the evaluation results,combined with the idea of polygon area segmentation,each UUV is assigned a task area that accords with its own ability.On the problem of sub-area coverage path planning,according to the different regional complexity,a simple area coverage path planning method based on comb scan line and a complex area coverage path planning method based on spanning tree are proposed respectively.At the same time,the improved ant colony algorithm is used to optimize the construction of spanning tree.Simulation results show that the proposed method is effective.Finally,In view of the increasing complexity of underwater operations,the search area is extended to an unknown underwater environment.Combined with the characteristics of multiUUV collaborative search in unknown environment and the motion limitation of UUV,propose a random search strategy based on sub-region pattern.In order to improve the blindness of the random algorithm,the selection of random target points is controlled in the UUV real-time detection window.At the same time,under the grid environment model,the unsearched grid linked list and the searched grid linked list are established to prevent UUV from falling into the situation of repeatedly searching a grid area.In order to improve the adaptability of UUV in unknown environment,the dynamic window method is applied to the real-time obstacle avoidance of UUV,and the feasibility of the above method is verified by simulation.