Research N Robust Consistency Of Multiple AUV Formation Based On Virtual Leader

In recent years,with the rapid development of the marine industry,autonomous underwater vehicles(AUVs)have shown unique advantages over other traditional submersibles.However,a single AUV operation is limited.The multi-AUV formation control has the advantages of efficient operation and strong fault-tolerance,and it is worth studying in depth.This paper focuses on the hot issue of AUV formation control in the current marine industry.The research on AUV formation control method and formation synchronization consistency mainly includes the following aspects:First,establishing the North East coordinate system and the carrier coordinate system,combined with the kinematics and dynamics characteristics of the AUV,a six-degree of freedom model is established,horizontal plane model is simplified according to the needs of the research in this paper,and the constant rotation test is conducted with or without currents.Secondly,the formation control of the pilot-follow method is improved,and a virtual leader with the same motion characteristics as the AUV is designed as a guidance system for the formation.The virtual leader can ignore the influence of the currents.The formation strategy used between the virtual leader and the follower AUV represents the relative displacement between each AUV and the virtual leader and represents the vertical angle with the virtual leader.The position tracking error model is established.For the characteristics of AUV nonlinear,the nonlinear system is linearized by the backstep method.The robust controller design and stability analysis are combined with the Lyapunov function.The AUV formation is implemented under the action of the designed controller.Digital path tracking.Thirdly,considering the influence of unknown currents on the robustness and stability of the AUV formation,so that all AUVs can achieve perturbed formation control,a virtual leader is still designed to give the followers accurate expected position information and speed information.The nonlinear speed controller is designed based on the backstep method to ensure the path tracking of the AUV formation.The current interference of the AUV in the marine environment is considered as a constant value or a slow-varying system input parameter,and adaptive technology is applied to estimate compensation.In order to ensure the robustness of the AUV formation under the interference of the currents,the Lyapunov function is applied to prove that the error system is gradually stable,and the simulation test proves that the AUV formation can complete the path tracking under the sine line.AUV has good consistency in state variables such as longitudinal velocity,transverse velocity,and rotation rate.Finally,aiming at the problem of formation stability at the inflection point in the formation test of the sine line above,a method of cross-coupling synchronization control is proposed.This method emphasizes the equality of each AUV,and the virtual leader designed in this paper is just right.The status of the AUV individual is the same.Cross-coupled state information includes position error signals,synchronous position error signals,and speed error signals.It is proposed to use the communication topology structure in graph theory to represent the information flow between AUVs.Using the idea of cross-coupling,the simultaneous position error of the AUV is in the position coupling error of the adjacent AUV in the opposite direction.The purpose is to make the coupling error of the adjacent AUV converge in the opposite direction,helping to weaken the influence of the synchronous position error.Bring it down to zero.Finally,the path tracking test of sine and circle curve is carried out,and the experimental structure proves the effectiveness of the proposed crossover control algorithm.