Multi-AUV Hybrid Formation Control Based On Virtual Leader

In order to explore the unknown marine environment,scientists have studied the Autonomous Underwater Vehicle(AUV).In recent years,agents have developed in the direction of group movements,of course,AUV is no exception.At this stage,in the face of complex marine environment,multi-body AUV can compensate for the lack of monomer AUV performance in addition to the space utilization rate.Regarding multi-AUV control,it is more common in engineering practice to control multiple AUV formations.In the face of multiple ocean missions,people often require more autonomy to perform.For example,the formation of multiple AUV formations,multi-AUV trajectory tracking,multi-AUV fixed-point positioning.In summary,this paper considers the formation control of multiple formations under the influence of constant current currents,and completes multi-AUV formation control,trajectory tracking control and fixed-point positioning control with the formation control strategy based on virtual leader,and finally combines hybrid switching control.The theory completes the hybrid formation control system.The main contents of this paper are as follows.Firstly,a six-degree-of-freedom model is established for AUV.According to the characteristics of multi-AUV hybrid formation control based on virtual pilots,the AUV six-degree-of-freedom model is simplified into a horizontal model.The model was simulated and verified under the disturbance of constant current current.Secondly,based on the formation control strategy of the virtual leader,a multi-group trajectory tracking control method based on the guidance of the Euler-Lagrangian error system is proposed in the directional communication topology.Completed multiple AUV formation control and multiple AUV trajectory tracking control tasks.In terms of the guidance system,the passive pilot is used to design the mobile controller of the virtual pilot AUV.Finally,the stability principle of Lyapulov stability and the related properties of the directed equilibrium diagram are used to prove the stability of the whole system,and the simulation is verified under the condition of ocean current interference.Thirdly,the virtual leader's formation control strategy is still used to achieve multi-point positioning control.For a fixed-point positioning control system,the response speed must be fast under the premise of good stability.Therefore,a multi-AUV fixed-point positioning control method based on the guidance-control structure design is proposed by combining the back-sliding mode method with good stability and fast response speed.In the directionalcommunication topology,the multi-AUV fixed-point positioning controller is designed according to the expected information given by the virtual leader,so that the multi-AUV can reach the desired posture stably and quickly.For the convenience of experiment,the paper gives a simple and simple multi-AUV trajectory tracking controller based on backstep sliding mode,and carries out simulation verification under constant ocean current interference.Finally,according to the hybrid switching control principle,based on the most core supervisor in the hybrid switching system,the switching index function and the hysteresis switching logic are designed.Combined with multiple formation controllers,multiple AUV trajectory tracking controllers and multiple AUV fixed-point positioning controllers,a hybrid formation switching controller is designed for multiple AUVs to form a hybrid formation control system.In order to verify the effectiveness and practicability of the hybrid formation control method.Under the constant sea current disturbance,a small experiment was carried out for the round-up of the disabled target.The round-up process reflected the switching of multiple controllers,the switching of the virtual pilot's trajectory and the switching of the formation,which improved the hybrid.Formation control system.