Unmanned Surface Vehicle Tracking Control Using Active Disturbance Rejection Control

Unmanned surface vehicle(USV)which can effectively promote the standards of the automation,has broad application prospects in the civilian and military fields.Path following and trajectory tracking control strategies are the guarantees to successfully complete a variety of missions for USVs.At present,most USVs are designed to be underactuated systems.In addition,the strongly coupling nonlinearity and complex sea status make tracking control one of the research hotspots and difficulties.Therefore,this article make the research on path following,trajectory tracking control and the practical control systems of USV.The main research contents are as follows:Considering multiple uncertainties the three degrees of freedom mathematical model of USV combined with parameters perturbation and external disturbances was set up to lays theoretical foundation and pave the way for the following sections of path following,trajectory tracking,and the application of active disturbance rejection control.As the path following control of underactuated USVs,sliding mode active disturbance rejection control algorithm was proposed based on the line of sight(LOS)guidance law.Firstly,considering the individual USV,the desired heading angle is obtained by LOS guidance law.Then multiple uncertainties are estimated by extended state observers(ESO)and compensated combined with exponential sliding mode approach law.The heading angle and forward speed controllers are designed by sliding mode active disturbance rejection control,and stability analysis are provided.In comparison with simulated experiments,the results demonstrate that the developed controllers can effectively alleviate the chattering phenomenon in a conventional sliding mode control system and improve the system robustness.Moreover,considering the multiple USVs along one curve,the desired forward speed can be developed via reduced order extended state observer.The forward speed which can be controlled by the aforementioned sliding mode ADRC algorithm to converge to the desired value,can keep the average distance with other USVs.Then the coordinated path following algorithm of USVs is proposed.As the trajectory tracking control of underactuated USVs,a guidance law designed specifically for trajectory tracking problem is proposed,and the dynamic surface control(DSC)method which modified by ADRC is adopted to realize the control of USV.Fitstly,the desired heading angle and forward speed are obtained by the trajectory tracking guidance law.Then the multiple uncertainties are estimated by reduced order ESO and compensated via DSC technique.Considering the widely-used discrete systems in real-world systems,nonlinear tracking differentiator(TD)is adopted instead of the first-order filter in DSC technique to track the commanded variables and obtain their derivative values.In the simulation experiment,by tuning the desired heading angle and forward speed,and combining with the ideology of arrange transition process in ADRC technique,the trajectory tracking simulation is achieved with input saturation constraints.Simulation result shows the proposed algorithm can effectively deal with the input saturation.In order to facilitate path following and trajectory tracking algorithm to practical applications,for the actual USV system,the whole structure of USV system is analyzed.In particular,the navigation and guidance module was designed.Finally,for the propulsion modes of the actual USV which adopt waterjet propulsion droven by diesel engine,this paper analyzed the operation methods of power control module.It offers means to the application of tracking control algorithm proposed in this paper.