Simulation Study On Vehicle Loading Layout Optimization And Scheduling On Ro-Ro Ship

The vehicle loading efficiency of ro-ro ship is an important evaluation index of ro-ro ship efficiency.It is related to the voyage income of the ro-ro ship.Good vehicle loading efficiency can reduce the stop period of the ro-ro ship at the wharf and improve the port scheduling efficiency.In this paper,the vehicle layout and scheduling problems in the process of vehicle loading on ro-ro ship are analyzed and studied,and the influence of ramp layout on vehicle loading is preliminarily simulated and analyzed.Aiming at the discontinuity of loading space caused by a large number of struts and interdeck ramps inside the ro-ro ship,this paper focuses on the path planning and path tracking control algorithms that meet the constraints of vehicle low speed motion,and vehicle layout optimization algorithms.For the multi-obstacle discontinuous deck environment,an improved RRT algorithm was established in the aspects of waypoint expansion speed,vehicle physical constraints and path smoothing,and the simulation was carried out.The improved RRT algorithm can improve the search efficiency and path quality,and can adapt to different ro-ro loading environments.Reeds-Sheep curve planning algorithm was used for path planning in spacious environments such as wharves and parking environments at the end of RRT paths,so as to ensure that vehicles travel along the shortest path.The improved RRT algorithm and the Reeds Sheep curve planning algorithm were combined to form a single vehicle global path planning algorithm from the dock position to the deck target position.A path tracking control algorithm matching the movement of the ro-ro ship vehicle is established,and the simulation is verified by combining the path planning algorithm and tracking control algorithm.The results show that the path planning is reasonable and the tracking control is good.For the deck plane with irregular edges and multi-pillar,an optimization method of vehicle layout on board was established based on improved genetic algorithm.The vehicle layout was decoded and arranged using the improved lowest level algorithm.The simulation results show that the improved algorithm has a good optimization effect on the unutilized deck area and the algorithm has good stability.Based on the analysis of the constraint conditions of the multi-vehicle scheduling problem,the mathematical model of the multi-vehicle scheduling problem was established,the vehicle movement rules and collision conflict elimination strategies were formulated,and the flow of different scheduling schemes was determined.The simulation verification was carried out for different scheduling schemes,and the better scheduling schemes were compared and optimized.Unity3D engine was used to build a simulation platform for ro-ro ship vehicle loading,enabling users to establish different RO-ro ship structural environment models and different vehicle layout and scheduling schemes through quick parameter Settings of UI interface,and to carry out visual simulation.An 8000 CEU ro-ro ship was used as the environment model to establish the simulation condition.Comparing the single-layer and multi-layer loading schemes,the simulation results show that the multi-layer loading scheme can optimize the loading efficiency.By comparing different ro-ro ramp layout,the simulation results show that the straight-through ramp has higher loading efficiency than the spiral ramp in multi-layer loading.