Formation Control Of Unmanned Surface Vehicle Based On Active Disturbance Rejection Control

As a new type of offshore working platform,the unmanned surface vehicle has been widely used in marine exploration and military construction due to its modularity,unmanned and intelligent nature.However,because of the complex and varied characteristics in the marine environment,it can't accomplish the expected goal by relying on single vehicle operation.Formation control effectively compensates for the difficulty of completing difficult tasks for a single vehicle wit its unique high adaptability,fault tolerance,robustness and self-organization.It has become the focus in recent years.This paper mainly studies how the unmanned surface vehicle formation can guarantee the continuous sailing of the boats at the expected distance and angle in the presence of external disturbances and time delay of the actuator.The specific work of the paper is as follows:Firstly,the development of unmanned surface vehicle formation control is reviewed.The control method and mathematical model of unmanned surface vehicle formation are introduced.The three-degree-of-freedom movement of unmanned surface vehicle is selected to simplify the control model.The relative motion equation between the leader vehicle and the following vehicle is given by the leader follower approach.Secondly,the structure and principle of the Active Disturbance Rejection Controller is analyzed.Considering that ADRC has many parameters and difficult to set,Particle Swarm Optimization is used to optimize the parameters of the ADRC controller by using the advantages of faster convergence and simple implementation,thereby improve the performance of the controller.Thirdly,in view of the problem of delay in the actuator,this paper proposes to add a delay link at the input of the state observer to make the control input delay the same time as the system delay.Since the delay time is unknown during the actual navigation process,this paper considers the method of generalized cross-correlation estimation to estimate the time delay existing in the actuator.In this way,the synchronization of the control loop and the observation loop time delay information is realized,which avoids the controller oscillation caused by time delay and reduces its adverse effects.Finally,according to the established control method,taking into account the influence of wind flow and the delay of the actuator,taking the leading follower formation control model of five unmanned surface vehicle as an example,adopting the Active Disturbance Rejection Controller to join the generalized cross correlation delay estimation link.The simulation results show that the controller has good robustness and adaptability and can keep the USV in the expected formation.