Research On Cooperative Control Method Of Heterogeneous Ship Formation Passing Through Lock

Ship lock is the basic control node for inland river navigation.Developing ship formation navigation control is an important means to improve the navigation safety and efficiency of ship lock waterway.In view of the characteristics of ship formation navigation in lock area,such as limited area,close spacing and difficult maneuvering,this paper focuses on the study of the navigation control of ship formation with heterogeneous maneuverability,designs centralized upper control and lower motion controller for ship formation navigation in lock area,and puts forward the control method of ship formation navigation based on model predictive control.The simulation environment are validated.The main research work and results are as follows:(1)Modeling the ship’s lockout movement,describing the kinematics,dynamics and expected trajectory characteristics based on the inertial coordinate system,the body-following coordinate system and the SF coordinate system.On the basis of comparing various existing ship motion models,Fossen hydrodynamic model is selected as the simulation object.The longitudinal speed control problem is further decoupled,and the direct navigation motion model is obtained.For the formation coordination problem,the spacing and azimuth are modeled,and the ship formation model in lock water area is obtained,which provides conditions for subsequent control research.(2)To solve the problem of coordinated speed control for ship longitudinal lock entry,the reference speed is set by speed-time method and speed-displacement method to complete the design of MPC controller for single ship stopping.On the premise that the navigation ship completes the stopping according to the above two methods,the MPC controller for three ship stopping is designed by adding the following ship movement.Finally,the simulation verifies the effectiveness of the stopping cooperative control.By comparing the two reference speed setting methods with the designed economic,smoothness and navigation efficiency indicators,the speed displacement method is more economical,but the speed-time method has a significant advantage over the peer efficiency.(3)Various factors affecting ship maneuverability are validated by ship model.The results show that the braking limit,braking force increment and ship loading all have an impact on the braking distance of the ship,among which the influence of ship loading is most significant.The rotating moment has a significant effect on the ship speed.The larger the rotating moment,the more the rotating speed will decrease.However,the limit of slewing moment will affect the ship’s slewing diameter,but whether the ship is fully driven or not has little effect on the slewing diameter.Based on the above validation,a heterogeneity index is proposed to reflect individual ship maneuverability differences in the controller.(4)Select the Three Gorges Lock as the research scene,build the scene model,delimit the task settings of the four stages,design the control reference of each stage according to the task requirements of different stages,and set the task switching options.The maneuverability heterogeneity is manifested by designing dynamic ship spacing reference values that vary with maneuverability and optimizing the difference of maneuverability indices in the objective function.A propagation queue cooperative gate-crossing controller considering the maneuverability heterogeneity is designed,and the simulation verifies the effectiveness of the controller to the ship’s gate-crossing navigation control.The navigation conditions of ships in the lock area are complex.The strategy of formation gate-crossing can effectively provide the navigation efficiency and safety of ships.When navigating in a lock,the heterogeneity of individual maneuverability of the ship has an important impact on the navigation of the ship formation.To include the design of heterogeneity of maneuverability in the overall planning of the gate-crossing task,it can better ensure the safety of the formation and the spacing of the ship,which is of great significance to the study of the gate-crossing navigation.