Navigation Control Of USV Based On Trajectory Linearization Control

Unmanned Surface Vehicle(USV)is a kind of intelligent small surface platform which can realize autonomous navigation by means of onboard sensors.As an important part of the unmanned system,the development of USV is very important for the development of the national marine industry and the maintenance of marine rights and interests.In order to ensure that the USV can carry different mission loads to successfully complete various tasks,it is required that the USV should have fast and accurate heading and track control performance and strong anti-interference ability.In this paper,the design and verification of the heading and track controller are carried out for the "Lanxin" US V,considering the influence of unmodeled dynamics and external disturbances such as wind,waves,and currents on its motion.The specific research contents are shown as follows:Firstly,the linear mathematical model,the nonlinear mathematical model and the stern model of the "Lanxin" USV are established in this paper,which lays the foundation for the analysis and design of the heading and track controller.Considering the influence of external disturbances such as wind,waves,and currents on the movement of the USV,the mathematical model of disturbance is established.Aiming at the heading control of the USV,this paper combines the nonlinear disturbance observer(NDO)with the trajectory linearization control(TLC),proposes a heading control method with time scale separation of fast and slow loops,and gives the corresponding stability analysis by using Lyapunov theory.In order to avoid the possible peak value phenomenon when the traditional trajectory linearization control algorithm uses the first order inertial link and the pseudo differentiator to obtain the differential signal,this paper uses the second order fastest discrete tracking differentiator to arrange a reasonable transition process for the command signal and its differential signal.The simulation results show that the heading controller can achieve accurate heading tracking control and has good robustness.Aiming at the track control of the USV,on the basis of the trajectory linearization control based on nonlinear disturbance observer,the indirect and direct track controllers are designed using the LOS guidance algorithm and the nonlinear coordinate transformation.The simulation results show that the indirect track controller can achieve linear and curve track control well in the presence of uncertain factors,and the direct track controller can achieve linear track control well and has certain anti-interference ability.Finally,in order to verify the effectiveness of the designed heading controller,a real ship experiment of heading control was carried out on the basis of the self-designed experimental system.The results of the real ship experiment show that the heading controller based on trajectory linearization control can achieve good heading control in the real marine environment,and provides an effective control method for the heading control of unmanned surface vehicle.