Research On Multi-AUV Thermocline Observation Method

With the development of scientific research and the increasing demand of human for Marine resources,the observation and research of Marine characteristics by researchers are also increasing gradually.Thermocline is closely related to Marine fishery,Marine military affairs,ocean circulation and internal waves,so it is of great significance and research value in the field of Marine research.Because the temperature of the ocean thermocline varies greatly in the vertical direction of the water body and is easily affected by various factors such as ocean current,monsoon and solar radiation,Autonomous Underwater Vehicles(AUV)are now a common and effective system platform for tracking the ocean thermocline.By giving full play to the characteristics of high autonomy and rapid deployment of AUV,rapid observation and continuous tracking of oceanographic thermocline can be realized.In addition,with the development of clustering technology,multi-AUV cooperative tracking thermocline has more incomparable advantages.Therefore,it is of great theoretical significance and practical application value to study the tracking technology of ocean thermocline by AUV and the cooperative formation technology of multi-AUV.Therefore,the main research contents of this thesis are as follows:In this thesis,the main characteristics of the ocean thermocline and the principle of "Explore 100" AUV platform adopted in this thesis are firstly introduced,and the components of "Explore 100" AUV are analyzed.Aiming at the problems of water layer thickness and thermocline boundary in the ocean,the advantages and disadvantages of several current tracking algorithms for ocean thermocline tracking were studied,and an AUV thermocline tracking method based on vertical gradient method was proposed.After the temperature gradient value is obtained,the upper and lower boundary of the thermocline is obtained by comparing the obtained temperature gradient value with the specified threshold value of thermocline temperature gradient,and then whether AUV enters the thermocline and successfully realizes AUV autonomous detection and tracking of the thermocline.For underwater robot formation method,this thesis studies the method of formation based on pilot-follower,according to the research of several types of the fleet formation,formation movement formation are adopted and designed a dynamic model of the horizontal plane fell on the simulation design of formation by adjusting parameters of formation and formation and transformation,This provides a basis for multiple AUVs to track the ocean thermocline.Finally,based on the above single AUV tracking thermocline and multi-AUV formation algorithm,the problem of multi-AUV cooperative detection of ocean thermocline was studied,and the underwater acoustic communication between AUVs was analyzed when multi-AUV cooperative tracking of thermocline.The underwater acoustic communication protocol based on Sea Linx framework was adopted.Finally,it describes the process and method of multi-AUV tracking thermocline to collect the whole data.Through the simulation analysis of the AUV field test data,it successfully realizes the multi-AUV cooperative detection and tracking to the thermocline.