Research And Application Of Block Storage Yard Scheduling

With the development of information technology,the shipbuilding mode keeps changing toward the trend of intelligence and elaboration.As a kind of large-scale equipment,ships need to be divided into many blocks to be manufactured.After the block leaves the processing position in the manufacturing workshop,it requires pre-outfitting,painting and major assembling before it can be sent to the shipyard and equipped.Due to the limitation of workshop spaces,half-finished blocks often need to be moved to the block yard for temporary storage,inspect and repair.The blocks are transported using a flat transporter in the yards.Because of its large size,the flat transporter needs a lot of space on the route,otherwise the removal of many obstructive blocks will incur a lot of cost.In order to reduce the cost related with moving obstructive blocks,the scheduling of a block yard should optimize the placing positions of blocks as well as the execution order of block tasks.To solve the block yard scheduling problem,the theses has done the following research.For the scheduling of a single yard,construct a model minimizing the block move degree to obtain the schedule with the lowest logistic cost of block yard.The order of block tasks and the position of an inbound block are optimized by adopting a multi-chain DNA genetic algorithm.At the inbound and outbound stage of a block,by mapping the connective relation and occupation status of yard positions to a node distance graph,obtain the route with the least obstructive blocks using the shortest path algorithm.Propose five move strategies for the blocks obstructing the routes,and compare the results of the five strategies in the scheduling experiment.For the scheduling of multiple block yards,based on the work stages of ship blocks and the preference of yard positions to the blocks at different work stages,set the priority of block placing.Construct the scheduling model that takes the minimization of block move degree as the objective.Divide the scheduling task into multiple phases to solve,and propose two solutions strategies at each of the block task sequencing phase,target yard position selection phase,and obstructive block moving phase.The proposed strategies are evaluated with experiments and compared with the existing scheduling methods used by the factory.At last,through developing a block yard scheduling information system,apply the proposed model and algorithms to practice.The system contains interactive user interface to realize the management of background information as well as the application of foreground scheduling modules.