Research On Dynamic Tracking Control Of Underwater Targets Using Unmanned Surface Vehicle

Unmanned Surface Vehicle(USV)has highly broad application prospects in marine science and other fields.Humans expect to monitor information of the underwater target in real time,including motion status and underwater operation,etc.One of the key technologies is dynamic tracking control of underwater targets using USV.Therefore,for the specific application scenarios of underwater target tracking and positioning,this paper mainly takes researches on tracking controller design,solution algorithm of tracking problem and tracking algorithm under the condition of weak connectivity.The main contributions are as follows:Considering external environmental disturbances,the three-degree-of-freedom mathematical model of USV motion with wind disturbance is established,which provides theoretical foundation for the research on dynamic tracking control algorithm of underwater targets using USV.For the tracking control problem of underwater targets,a state-dependent Riccati equation(SDDRE)technique is used to solve this problem.Firstly,the nonlinear system is converted into a state-dependent linear form to effectively solve the complexity of controller design.Secondly,considering the linear model of error,solution of the optimal control input based on the SDDRE method is applied to the control system to stabilize the system and obtain a faster convergence rate.Then,establishing a new state-dependent coefficient(SDC)matrix reflects the relationship of each state variable,and improves the controller performance and control effect.Finally,the effectiveness of the controller is verified through theoretical analys is and simulation experiments.For the problem of SDDRE solution complexity,a solution algorithm based on Legendre-Gauss-Radau(LGR)pseudo-spectrum method is proposed.Firstly,to effectively solve the complexity problem of solution,a mathematical model of continuous-time optimal tracking control problem with multiple constraints is established.Then,considering the balance on the solution accuracy and velocity of the SDDRE problem in the tracking process,a solution method based on the LGR pseudo-spectrum method is proposed,which derives the semi-analytical formula of the optimal control input to realize the real-time calculation of the SDDRE tracking problem.Finally,simulations verify the effectiveness and efficiency of the algorithm for solving SDDRE problems.For the problem of tracking underwater targets under the condition of weak connectivity,a method for dynamically predicting the target position based on the target’s historical trajectory and other information is proposed.First ly,the tracking control target is selected and the system error equation established when describing the mathematical model of the tracking problem under the condition of weak connectivity.Secondly,considering problem of unknown underwater target position during the interruption of underwater acoustic communication,design ing the target trajectory prediction algorithm through the historical trajectory dynamically predict the target position at the next moment,to achieve the purpose of continuous tracking.Then,for the difference between the actual trajectory and the predicted trajectory,the trajectory prediction algorithm is further optimized to continuously track the target.Finally,the simulation verifies the real-time and rationality of the tracking algorithm under the condition of weak connectivity.