| Unmanned Underwater Vehicle(UUV)carries a variety of detection equipment is a powerful tool for ocean detection.Different detection devices are organically combined to improve the detection capability of UUV group for underwater targets by using the formation coordination capability of UUV group,so the control problem of UUV group formation transformation from rough to detailed detection is studied in this paper.The formation change process is the UUV group from a loose position at the end of the rough detection,gathered around the suspected target by formation transformation,then close to the suspected target and form a new formation,and finally the UUV group’s formation control demand for further detection of the suspected target is met.The main research contents of this paper are:Firstly,the task background of rough screening and detailed detection is described and analyzed.The formation transformation control requirements are presented,as well as the distance and formation control requirements when the UUV is distributed around the suspected target for detection.In response to the control requirements,the control strategy for formation transformation setting aggregation points and detection points to guide the group is proposed.Then the UUV equations of motion are established and verified,its motion characteristics and motion states under current disturbance are obtained.Secondly,the aggregation point optimization objective function is established.The particle swarm optimization algorithm is used to derive the optimal aggregation point to reduce the length of UUV motion paths and path crossings to improve the efficiency of formation transformation and the safety of UUV.To achieve state consistency when the UUV group completes the formation transformation,the position consensus is decomposed into longitudinal consensus and bow control,and the UUV longitudinal consensus protocol and bow control law are proposed and verified to be effective.In order to offset the effect of currents on the consensus control effect,the consensus method combined with active disturbance rejection control is proposed.And to address the problem that the ideal velocity cannot be tracked when the velocity is full due to the disturbance of the sea current,the velocity limitation method of the disturbance-free model is proposed,and its effectiveness is tested by simulation cases.Again,for the problem of possible collision during the formation transformation of the UUV group,the virtual force method is improved,the avoidance method based on virtual torque field is proposed.And an avoidance speed control law is designed to reduce the speed of the UUV during avoidance.The avoidance function shutdown condition is set so that the UUV group continues to approach the suspected target after reaching the aggregation point.Then the virtual spring network is designed to provide virtual force to enable the UUV group to meet the requirements of distance control and formation control when detecting suspected targets at close range.Finally,the control strategy and method of UUV group formation transformation from rough to detailed detection proposed in this paper are simulated and verified.The effect of the avoidance method based on virtual torque field,the effectiveness of the formation transformation strategy and control methods,the effect of the aggregation points obtained by the particle swarm optimization algorithm to improve the efficiency of formation transformation,and the effectiveness of the detailed detection formation control method based on virtual spring network have been verified separately.The above simulation results show that the control strategy and method proposed in this paper have achieved the desired effect,so that the UUV group has accomplished the control objective of formation transformation from rough to detailed detection. |
