Research On Fixed-time Formation Control Of Multi-AUVs Based On Event-triggered

Autonomous underwater vehicle(AUV)has been applied in various fields.The research on multi-AUVs not only makes up for the shortcomings of the single AUV in the complex underwater operation requirements,but also improves the efficiency of the operation.At the same time,formation control has the advantages of strong adaptability and high resource utilization.Therefore,based on the leader-follower formation strategy,distributed event-triggered mechanism and fixed-time control theory,the formation control problems in multi-AUVs are studied in this paper.The detailed research work is as follows:First of all,in order to reduce the energy consumption of information exchange and controller update of multi-AUV formation systems,and to accelerate the convergence speed of formation,a fixed-time formation control strategy based on distributed static event-triggered mechanism was introduced.For the purpose of reducing the complexity of controller design,the problem of "computational explosion" is avoided based on the backstepping-dynamic surface control algorithm.And the distributed static event-triggered mechanism and the fixed-time control theory are introduced into the multi-AUVs formation strategy simultaneously.Thus,the controller is designed to achieve the system fixed-time convergence.The convergence time is independent of the initial state and it is proved that there is no Zeno behavior.The effectiveness of the proposed algorithm is verified by simulation.Secondly,aiming at the formation control problem of multi-AUVs with unknown external disturbance and uncertain model parameters,a disturbance observer based on fixed-time is designed to estimate the disturbance accurately.Based on the dynamic surface control algorithm,a fixed-time anti-interference controller based on eventtriggered is designed.As well as introducing dynamic variables on the basis of distributed static event-triggered mechanism with fixed thresholds,such as dynamic event-triggered mechanism is designed,and combined with Lyapunov stability theory,the system can achieve fixed time convergence.The rationality of the algorithm is verified by simulation.Finally,in formation control of multi-AUV systems with unknown external disturbances,the influence of input saturation is considered.Based on the hyperbolic tangent function and the adaptive radial basis function neural network,the nonlinear term and disturbance of the system are estimated.Based on the backstepping-command filtering control algorithm,a compensation mechanism is constructed to reduce the influence of filtering error and avoid the problem of "computational explosion".Then,combined with the fixed-time theory,distributed static event-triggered mechanism and digustributed dynamic event-triggered mechanism,an adaptive radial basis function neural network based distributed event-triggered fixed time anti-saturation formation controller is designed,so that all signals of the system are guaranteed to achieve bounded convergence in a fixed time.Moreover,digustributed dynamic event-triggered mechanism can maintain the same control performance as distributed static event-triggered mechanism while further reducing energy consumption.The rationality of the algorithm is verified by simulation.