Study On Highly Mobile Autonomous Robot For Underwater Target Search

The ocean is the treasure house of the earth’s energy and the battlefield of military strategic deployment.As the exploration of ocean resources and the search for underwater targets become more and more widely used,Target detection and search based on Autonomous Underwater Vehicle(AUV)has become one of the important research directions in Marine military and people’s livelihood science and technology.However,there are still many problems to be solved in the field of underwater target detection.First of all,underwater target detection mainly adopts towed sonar or deployed array sonar to realize underwater acoustic data acquisition.The acquisition process is not only time-consuming and laborious,but also the data cannot be timely and effectively processed.Secondly,the acoustic detection results are often interpreted manually,so it is urgent to improve the intellectualization of exploration and the efficiency and accuracy of search.To solve the above problems,this paper developed an underwater search robot with the functions of high maneuverability cruise search and autonomous acoustic target detection,and studied the algorithm of high maneuverability cruise control and acoustic target detection for underwater robots.This paper developed a high maneuverable robot for underwater target search to accomplish typical target search tasks in typical waters.For the motion and attitude control requirements of AUVs in underwater search tasks,this paper designed a six-degree-of-freedom underwater robot mechanical structure,established an underwater robot dynamics and kinematics model,and used the Proportional-Integral-Derivative(PID)control method to achieve high maneuverable motion and attitude control of AUV.For the requirements of constant depth cruise and acoustic data collection in underwater search tasks,this paper,based on high maneuverable motion control and full coverage cruise path planning,used a trackpoint path tracking controller to achieve AUV underwater cruising,detection,and search in the task waters.The simulation results of Simulink verified the effectiveness of high maneuverable motion control and full coverage cruise detection.In order to solve the problem of underwater acoustic target detection,a target detection algorithm based on heterogeneous filter detection and level set segmentation is proposed in this paper.The acoustic target detection is realized through the steps of super pixelation,filter detection,adaptive threshold processing,target fine segmentation,etc.Firstly,in view of the heterogeneity between bright and dark areas in sonar images,a heterogeneous filtering method is proposed to eliminate the intensity heterogeneity of sonar images.Secondly,by analyzing the local mean and variance of acoustic images,an adaptive threshold detection method is proposed to eliminate false targets and obtain the position and initial shape of real underwater targets in sonar images.Finally,in order to obtain the precise contour of acoustic targets and facilitate subsequent target recognition and location calculation,an improved level set method is used in this paper to establish an energy model based on the contour constraint of superpixel segmentation,and the precise contour of acoustic targets is segmented through model topological evolution.Simulation results show that compared with traditional detection methods such as cluster recognition and evolutionary segmentation,the acoustic target detection algorithm proposed in this paper can not only realize underwater target detection,but also improve the success rate of target segmentation,position and size fitting synthesis power by about 3%.In addition,a functional prototype of an underwater search robot was built in this study,and experiments on underwater high maneuvering motion control and target detection search were conducted.The experimental results show that the underwater search robot designed in this study can achieve high maneuvering cruise path tracking and acoustic data collection based on autonomous cruising path planning,and can realize underwater target detection and position calculation through the proposed acoustic target detection algorithm,completing underwater target search tasks.