Study On The Track Tracking Control Problem Of Catamaran Unmanned Surface Vehicle

As countries pay more and more attention to the exploration and exploitation of marine resources and the maintenance of sea rights,more and more disputes are taking place on the ocean.Catamaran unmanned surface vehicle is an ocean platform that takes into account civil applications such as resource exploration and mining and military applications such as nearshore reconnaissance and defense.With its higher stability and roll suppression capabilities,it has become a hot-spot in the field of marine equipment research in various countries.As the basis for ensuring the safe and effective operation of unmanned surface vehicle,the motion control of unmanned surface vehicle has attracted more and more attention in the field of control research.Among them,the research on trajectory tracking control has been and is still the key research spot in the field of unmanned surface vehicle motion control.However,the working environment of the catamaran unmanned surface vehicle is a complex and changeable marine environment,which is highly nonlinear and time-varying,and the unmanned surface vehicle itself also has problems such as parameter perturbation.Here comes a huge challenge in the research for the motion control of the catamaran unmanned surface vehicle.In this paper,the track tracking controller for the catamaran unmanned surface vehicle is carried out subjected to the unmodeled hydrodynamics,model-uncertainty,and time-varying external disturbances.The main research contents of this paper are concluded as follows:1.Aiming at the problems of the inability to accurately establish the dynamic model and the nonlinear and time-varying external disturbance during the trajectory tracking process of the catamaran unmanned surface vehicle,a Minimum-Learning-Parameter(MLP)-based uncertainty estimator is designed to approximate and compensate the adverse effects of disturbance.Adopting the sliding-mode variable structure control,a finite-time trajectory tracking control mechanism for catamaran unmanned surface vehicle is constructed,with introducing the hyperbolic tangent function to reduce the sliding mode control chattering problem and improve system stability.2.Aiming at the problems of inability to accurately establish dynamics model,parameter perturbation,nonlinear and time-varying external interference during the trajectory tracking process of catamaran unmanned surface vehicle,a prescribed performance method based robust model-free control scheme is designed.With the help of appropriate prescribed performance functions,the control system has the ability to constrain the evolution of the tracking error within the prescribed region;subsequently,based on sliding mode control technology,a robust control scheme is developed which is independent of model information and adaptive laws.3.Aiming at the problems of nonlinear and time-varying external disturbances and limited parameter adjustment time in the actual marine environment,a self-tuning PID controller based on a finite-time disturbance observer is designed.Using PSO particle swarm optimization algorithm for PID parameter tuning can effectively reduce the difficulty of parameter adjustment.In addition,a finite-time disturbance observer is designed to observe external disturbances to improve the robustness of the system.