| With the sharp increase of car ownership,domestic large and medium-sized cities due to the lack of parking Spaces,has seriously affected people’s lives,and caused traffic jams,therefore,to solve the problem of difficult parking has been imminent.Automatic three-dimensional garage has many advantages,such as saving land,improving the level of parking automation and management,making full use of urban space and so on.It is an important part of the rapid development of modern parking industry.The rational planning of the automatic stereo garage can make the limited geographical space be more fully utilized.The performance of the automatic stereo garage is mainly reflected in the aspect of operation efficiency.In order to improve the operation efficiency of the planar mobile stereo garage,this thesis mainly studies the garage location layout,equipment quantity matching,transportation equipment path optimization and access vehicle strategy.The planar mobile three-dimensional garage studied in this thesis relies on the AGV car on the ground level,the vertical main elevator,the horizontal running of the handling equipment,to achieve intelligent access car service.In order to improve the overall access efficiency of the garage and reduce the access time,this thesis firstly optimizes the system storage location layout and related equipment configuration.Then,a suitable optimization algorithm is selected for the path planning of AGV trolley on the ground plane to find a better path and solve the path conflict problem between multiple transport carts.Finally,find a suitable access strategy for the garage.The main research contents are as follows:1)Based on M/M/1 queuing model,the relationship between the average customer stay time and the number of entrances and exits is analyzed.Then,based on M/M/C queuing model and Matlab numerical calculation results,the number matching of four-point synchronous lifting mechanism and handling carts is studied,and the storage location layout is optimized,realizing the unified scheduling,management and coordination of related equipment in the garage system.2)In order to study the path optimization of single AGV,this thesis proposes an improved A* algorithm which introduces redundancy point removal and dynamic weighting.After analyzing the relevant data of the planar mobile stereoscopic garage,based on the raster network model,the improved A*algorithm is used to carry out the simulation operation.The results show that the number of path turns,the nodes passed by and the length of the running path are significantly improved,and the indicators required by the AGV to complete the task are optimized.3)In this thesis,the improved A* algorithm combined with the time window is used to realize the dynamic of the algorithm.By analyzing different conflict avoidance schemes,comparing the conflict occurrence times under different schemes and the time consumed to solve the path conflict problem,choosing a better path conflict avoidance scheme makes the operation efficiency of the conveyer trolley significantly improved.At the same time,the effectiveness of the proposed collision avoidance scheme is proved by numerical simulation results.4)Combined with the specific access process of planar mobile stereoscopic garage,the mathematical models of three traditional access vehicle strategies were established.Considering the different access conditions of flat peak,storage peak and pick-up peak,the average total service time of each vehicle in the system under different access strategies was obtained based on genetic algorithm and MATLAB simulation calculation.Select more efficient access strategy,improve the garage access efficiency,reduce the equipment energy consumption. |
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