Research On Production Scheduling Problem In An Integrated Environment With Consideration Of Multi-factors And Multi-processes

Process planning and scheduling are two important components in manufacturing system.In traditional manufacturing,they are performed independently in serial mode.The independent and serial mode of the two components may lead to unrealistic process route,uneven resource utilization and bottleneck in scheduling.Due to diverse customer needs and increasingly fierce market competition,traditional manufacturing can't satisfy the needs of modern manufacturing system,such as high efficiency and high flexibility.Integration of process planning and scheduling is an effective way to solve the above problems.Based on multi-processes,multi-constrains and multi-objectives in extended manufacturing process,various kinds of integrated process planning and scheduling(IPPS)problems are researched in this paper.The study has important meaning of theory and significant engineering application value.Based on the analyses of process panning and production scheduling,a running mode of integrated process planning and scheduling system is proposed,which is composed of layer of order,layer of process planning,layer of production planning,layer of scheduling and layer of manufacturing.Each layer is analyzed.Running process of the mode is discussed in this paper.Based on the above research,a mathematical model of basic IPPS problem has been established.Aiming at the features of extended IPPS problems,an universal multi-layer encoding structure is proposed.The structure is composed of layer of workpiece,layer of machine,layer of process method,layer of process route and other layers.A particle swarm optimization(PSO)and a genetic algorithm(GA)are proposed based on the multi-layer encoding structure to solve single objective IPPS problem.Due to particularity of date of delivery which is considered in IPPS problem,a three-phase decoding method is designed.A non-dominated sorting genetic algorithm-II(NSGA-II)based on the multi-layer encoding structure is proposed to solve a multi-objective IPPS problem.Assembly equipments,transportations and processing equipments are scheduling simultaneously in IPPS problem with consideration of assembly,transportation and manufacturing.The completed time of finished product is the objective.A mathematical model is built.A PSO is proposed based on the multi-layer encoding structure.The model and algorithm are proved through an application case.IPPS problem is studied in batch manufacturing environment in this paper.On the one hand,bill of material(BOM)is considered in IPPS problem.The completed time of finished product is the objective.A mathematical model of IPPS problem with consideration of batch and BOM is established.A multi-layer PSO is proposed based on the multi-layer encoding structure.On the other hand,the fixed batch splitting strategy may lead to the unbalance between machine and loading.In order to avoid the disadvantage,a flexible batch splitting strategy is adopted.The makespan is the objective which will be minimized.A model of IPPS problem with consideration of a flexible batch splitting strategy is built.A PSO is proposed based on the multi-layer encoding structure.The model and algorithm are proved through an application case.An IPPS problem with consideration of date of delivery and an IPPS problem with consideration of uncertain process time are studied in this paper.A three-phase decoding method is designed,which is composed of an active decoding within inserting,a reverse decoding and a correction.A GA based on the multi-layer encoding structure and the three-phase decoding method is proposed to solve an IPPS problem with consideration of date of delivery.In order to solve an IPPS problem with consideration of uncertain process time,triangular fuzzy number(TFN)is used to express uncertain process time.A GA based on the multi-layer encoding structure is proposed.Finally,the model and algorithm are proved through an application case.The basic IPPS problem is over idealized,and it may not adapt complicated practical manufacturing environment.The above extended IPPS problems are researched for solving the disadvantages of basic IPPS problem.The makespan,processing cost,maximum machine workload are the main targets which will be minimized.A multi-objective model of the problem is established.A multi-layer NSGA-? is proposed to solve the problem.The model and algorithm are proved through an application case.