Study Of Collision Avoidance Strategy And Finite-Time Path Following Control Method Of Intelligent Ship

With the development of artificial intelligence technology,intelligent ship technology is expected to effectively solve the problems faced by traditional ships in energy conservation and emission reduction,labor cost and navigation safety,and has gradually become a research hotspot in the global shipbuilding and shipping industry.Autonomous collision avoidance and tracking control are two key technologies for intelligent ships to realize safe navigation at sea.Taking intelligent ships as the research object,this paper studies the collision avoidance strategy and the guidance and motion control subsystem in the tracking control system.The main research work of this paper is as follows:(1)Aiming at the problem that the lateral deviation of underactuated intelligent ship is easily affected by factors such as path curvature and environmental force when performing the task of linear and circular path following,an adaptive guidance law with finite-time convergence is proposed,and its control parameters can be adjusted adaptively with the change of lateral deviation,So that the lateral deviation in the tracking process can converge to near zero in a finite time;For the parametric path,a finite-time guidance law based on drift angle observer is proposed.The finite-time disturbance observer is designed to estimate the time-varying large drift angle,which improves the tracking control effect of complex curve path;Finally,the effectiveness and superiority of the proposed finite-time guidance law are verified by simulation.(2)Aiming at the problems that the real-time performance of collision avoidance algorithm is poor and the re-planned collision avoidance path does not conform to the ship motion characteristics when the ship encounters unknown obstacles,a collision avoidance strategy based on the guidance principle of line of sight method is proposed which combined with the principle of artificial potential field,where the virtual guidance point in line-of-sight method is regarded as the gravity point moving in the artificial potential field and the obstacle is regarded as the repulsion point,then output the resultant force direction to guide the ship to avoid collision;In addition,an improved artificial potential field method is proposed to solve the problems of local minimum,unreachable target and difficulty in considering the international rules for preventing collisions at sea,whose improved repulsive potential field is a function of the relative position and relative velocity between our ship and obstacles;Finally,the effectiveness of the designed collision avoidance strategy is verified by simulation.(3)Aiming at the problems of time-varying environmental disturbance and model uncertainty in the path following task of underactuated intelligent ship,a finite time tracking motion control method based on back-stepping sliding mode control theory is proposed that the model uncertainty,time-varying environmental disturbance and virtual control quantity are regarded as total disturbances,and the disturbance observer is designed to estimate and compensate them which improve the robustness of the control system;Aiming at the problem of input saturation,the auxiliary dynamic system and filter compensation system are designed to effectively compensate the input saturation value and significantly improve the control effect;Finally,the finite time stability of all control signals in the control system is proved,and the effectiveness and superiority of the proposed method are verified by simulation.