Research On Active Disturbance Rejection Control Method Of USV Path Following

Currently,in the field of intelligent marine equipment research,the research of Unmanned Surface Vehicle(USV) has attracted the attention of many scholars.For the USV sailing in the ocean,it is the precondition for the USV to perform various tasks to ensure its navigation on the specified route and along the expected route.Therefore,it is very important to study the path tracking control of USV.In this paper,two kinds of Active Disturbance Rejection Control strategies based on dynamic surface control and non-singular terminal sliding mode control are studied respectively for the USV path following problem under time-varying sea wind disturbance,the main research contents are as follows:Firstly,The underactuated model of horizontal plane waterjet propulsion unmanned craft and the sea wind disturbance model are established,the rationality and reliability of the model are verified by simulation and comparison with the real ship.Secondly,A Dynamic Surface Active Disturbance Rejection Controller based on SFLOS is designed.First of all,SFLOS guidance algorithm is designed under the known sideslip angle to solve the problem that the traditional LOS guidance can only track the straight line path;Secondly,the Dynamic Surface Control algorithm is combined with the Active Disturbance Rejection Control theory,and the Dynamic Surface Active Disturbance Rejection Controller is designed from four parts: Using the tracking differentiator to arrange the transition process for the desired value of the heading angle and longitudinal speed,so as to make it stable and continuous;The nonlinear Extended State Observer is used to estimate the longitudinal wind force and the turning wind moment in real time;The dynamic surface control algorithm is used to design the yaw and longitudinal speed controllers respectively,which avoids the “differential explosion” problem of the backstepping method;The disturbance compensation is carried out in the controller by using the observation value of sea wind disturbance,which effectively suppresses the disturbance effect of sea wind.The simulation results show that the Dynamic Surface Active Disturbance Rejection Controller based on SFLOS guidance can make the USV track the straight line and sinusoidal path under the time-varying sea wind disturbance.Finally,A Non-singular Terminal Sliding Mode Active Disturbance Rejection Controller based on improved ELOS guidance is designed.First of all,under the condition of unknown sideslip angle,a sideslip angle observer is introduced to estimate and compensate the timevarying unknown sideslip angle,and the ELOS guidance algorithm is designed;Secondly,the Linear Extended State Observer is designed to estimate the longitudinal wind force and the yaw wind moment in real time,so as to solve the problems of theoretical analysis difficulties and parameter setting difficulties of the nonlinear Extended State Observer;The non-singular terminal sliding mode with better performance is adopted to design heading and longitudinal velocity controllers respectively,which can not only ensure the finite time convergence of tracking error,but also avoid the singularity problem of common terminal sliding mode;The disturbance compensation is carried out in the controller by using the observation value of sea wind disturbance,so as to eliminate the influence of sea wind disturbance.The simulation results show that under the condition of time-varying sea wind disturbance and unknown sideslip angle,compared with the control algorithm before the improvement,the improved method has faster convergence speed of tracking error and higher tracking accuracy when tracking straight line and sinusoidal path.