Research On The Distributed Formation Robust Control Of The Multiple Marine Surface Vehicles

In recent years,with the development of ship control technology,the formation control of multiple marine surface vehicles has become one of the hot topics.Compared with single vehicle,the formation of multiple marine surface vehicles has the advantages of higher efficiency,better fault-tolerant property and stronger adaptability.On the other hand,the formation of multiple marine surface vehicles has a wide range of applications,such as underway replenishment,seabed mapping,escort formation,marine patrol,formation mine clearance and so on.Therefore,the research on formation control of multiple marine surface vehicles is of important practical application value.In this paper,the uncertain model parameters and the time-varying environmental disturbances,the unavailable velocity measurements,the input saturation of actuator,the convergence performance of the system and the communication load are considered in the formation control of multiple marine surface vehicles.The main research contents are presented as follows:For the distributed formation control problem of multiple marine surface vehicles with uncertain model parameters and time-varying environmental disturbances,a robust control method for the multiple marine surface vehicles based on adjacent cross-coupling control strategy is proposed.Firstly,based on the position synchronization errors of adjacent vehicles and the tracking errors,the formation coupling error is designed by using the adjacent cross-coupling control strategy,and the weights of the tracking and synchronization actions can be adjusted by tuning the coupling coefficient.Then,the neural network and adaptive control technology are used to approximate the uncertain model parameters and unknown disturbances.A robust distributed formation control law for multiple marine surface vehicles is designed based on backstepping method.According to the Lyapunov stability theory,it is proved that the error signals of the system are uniformly ultimately bounded(UUB).Finally,the simulation results show that the attitude synchronization of multiple marine surface vehicles in the whole formation process is achieved,the synchronization accuracy between vehicles can be improved and the time of the formation generating can be shorten by using the proposed distributed formation robust control method.To solve the formation control problem for the multiple marine surface vehicles in the presence of complex uncertain disturbances,input saturation,and the unavailable velocity measurements caused by the speed sensor faults or the technical and cost factors,a distributed anti-saturation formation control method for multiple marine surface vehicles based on nonlinear extended state observer is proposed.Firstly,a nonlinear extended state observer is used to simultaneously estimate the velocity information and the overall disturbances of the vehicles,and the Lyapunov stability proof of the second-order nonlinear extended state observer is further improved.Then,to avoid the differential expansion caused by using backstepping control method,a distributed formation control law for multiple marine surface vehicles is designed by employing the dynamic surface control technology based on the outputs of the extended state observer,which does not depend on the accurate system model.Finally,for the input saturation problem caused by the physical constraints of actuators,the proposed generalized saturation function is embedded in the designed formation control law,which breaks through the limitation of using a specific saturation function.The distributed formation control of multiple marine surface vehicles is achieved under the multiple constraints such as complex uncertain disturbances,unavailable velocity measurements and input saturation,which lays a theoretical foundation for engineering applications.For the distributed finite-time formation control of multiple marine surface vehicles with uncertain disturbances and unavailable velocity measurements,a distributed formation finite-time control scheme based on finite-time extended state observer is proposed.Firstly,only based on the position information of the vehicles,a finite-time extended state observer is designed to simultaneously observe the velocity information and the total disturbance of the vehicles,and the finite time convergence of the observation errors is proved.Secondly,under the condition that only a subset of vehicles can obtain the state information of the leader,a finite-time output feedback distributed formation controller of multiple marine surface vehicles is presented by using the homogeneous method based on the observations.Finally,the finite time stability of the closed-loop system is guaranteed by using homogeneous theory and Lyapunov theory.Numerical simulations are presented to illustrate the effectiveness of the proposed finite-time output feedback formation control scheme.Compared with the traditional output feedback control method,the proposed finite-time output feedback control method can provide faster convergence speed,higher control accuracy and better disturbance rejection ability.To solve the problem of finite-time formation control for multiple marine surface vehicles with input saturation when the leader's acceleration is locally known and the velocity measurement is not available,an finite-time formation output feedback anti-saturation control method for multiple marine surface vehicles based on acceleration distributed finite-time estimation strategy is proposed.Firstly,considering the unavailable velocity measurements and the total disturbances of the vehicles,a double power extended state observer is proposed to simultaneously observe the velocity information and the total disturbances,which improves the convergence rate of the velocity observation error and disturbance observation error.Secondly,a distributed finite-time acceleration estimation strategy is designed,which eliminates the assumption that the navigation acceleration is globally known and achieves the estimation of the leader's acceleration in finite time.Then,a finite-time output feedback anti-saturation distributed formation controller for multiple marine surface vehicles is designed by using the homogeneous method and the designed saturation function.According to the homogeneous theory and Lyapunov stability theory,it is proved that the error signals in the closed-loop system can converge to zero in finite time.Finally,Simulation results show that the proposed finite-time formation control method can achieve good control performance even if the actuator input is saturated.