Integrated Scheduling Algorithm Of Multiple Workshops With Procedures On Same Type Machine

The scheduling method in manufacturing industry,can be basically divided into the following two categories: the flowshop scheduling method for the large quantities of the same product,and the jobshop scheduling method for the small quantities of different product,which is mainly pure processing scheduling or pure assembling scheduling.The integrated scheduling algorithm can process and assemble the product in parallel,which avoids the fragmentation of the internal manufacturing relationship.And the scheduling algorithm of multiple workshops is more suitable for the current manufacturing requirements.Aiming at the integrated scheduling problem that how to allocate a single complex product into symmetric two workshops,the dynamic essential path has effect on scheduling results,but in current studies,it has not been considered yet,therefore an integrated scheduling algorithm of two workshops based on essential path is proposed.Firstly the actual scheduled procedure is confirmed from schedulable leaf nodes according to the essential path of two workshops strategy.Then in order to decrease the number of procedure migration between two workshops and make workshops load balanced,different procedure scheduling strategy is chosen by judging the attribute information of the procedures in the processing tree,and the actual scheduled procedure is allocated to the proper workshop.The procedures with multiple sub-nodes are allocated into the workshop with less procedure migration number according to its immediate predecessor allocated into the procedures whose immediate successor has several sub-nodes are allocated into the workshop to make it begin processing as soon as possible.The procedures in the strings are allocated into the workshop that its immediate predecessor in.Finally,the procedure begin processing time is confirmed by First Fit strategy.In order to help readers understand the algorithm,the paper gives an example verification and algorithm comparison analysis.Aiming at the integrated scheduling problem of two asymmetrical workshop,the serial processing for procedures on same type machine will delay product completion time,the integrated scheduling algorithm of asymmetric two workshop considering the procedures on same type machine is proposed.First of all,the planed scheduling procedure and set are confirmed according to the relevant strategy and definition.And then the actual scheduling procedure set is formed according to the procedure selection strategy of same type machine in two workshops,and the long path procedure is scheduled firstly to shorten the product completion time.Then according to the procedure group scheduling balanced strategy in two workshops,procedures are allocated into proper workshop to reduce the procedure migration number and improve the parallelism and balance of two workshops.Finally the scheduling results and compared example shows that the proposed algorithm can efficiently solve the problem of single complex product scheduling in asymmetric two workshops.Aiming at the integrated scheduling problem that allocate a single complex product into asymmetrical multiple workshops,integrated scheduling algorithm of multiple asymmetrical workshops considering the procedure on same type machine is proposed.Firstly the planned scheduling procedure is confirmd according to long path strategy and short time strategy,and the planned scheduling procedure set is formed by the procedures on same type machine of the planned scheduling procedure.Then the actual scheduling procedure set is confirmed according to the procedure on same type machine with long path first strategy,finally the actual scheduling procedures are allocated into proper workshops according to the multiple workshops with procedure group scheduling balanced strategy.So it can shorten the total processing time of product,decrease the procedure migration number and improve parallelism and balance between workshops.The effectiveness of the algorithm is illustrated by example verification and algorithm comparison analysis.