一种改进的遗传算法在车调度中的应用

研究现代生产先进制造车间调度问题，对于发挥先进制造车间的高效性和灵活性具有十分重要的意义。生产过程的计划调度问题，是实现制造系统运筹技术、管理技术与优化技术的核心。因此，优化调度算法的性能直接影响到FMS的生产效率和应变能力。本文在传统的遗传算法的基础上，对车间调度算法进行了深入的研究。基于机床负荷平衡的思想，提出了面向先进制造车间的平衡遗传算法，并与传统的遗传调度算法进行了对比。 实验表明，该调度方法具有较高的可行性、有效性和稳定性。保证了各个机床的负荷平衡，满足了交付期的要求。     

关键链约束理论解决柔性车间调度问题

柔性作业车间的调度难题一直以来都是NP难题,随着加工零件数量和机床数量的增加,调度优化难度将会以呈指数倍增长。本研究提出以约束理论为基础依托,选用最小临界比规则及遗传算法,结合各自的优点对柔性作业车间基于关键链进行调度优化,有效的解决了传统遗传算法容易陷入局部最优和最小临界比规则鲁棒性不强等问题。使设计的调度算法更加地符合车间真实的制造生产状况,改善了制造过程中资源设备利用率相对较低的问题,把设计的算法和传统遗传调度算法解决典型的柔性作业车间难题得到的结论相对比,验证设计算法的优势。     

FPD-GA求解多目标柔性作业车间调度问题

针对柔性制造车间调度问题的特点,提出一种求解该类问题的定点扰动-遗传算法(Fixed Point DisturbanceGenetic Algorithm,FPD-GA)。根据车间生产实际构建以完工时间、机床负荷和设备使用率为目标函数的多目标优化模型。针对遗传算法局部搜索能力差、易早熟收敛的缺点,设计定点扰动策略,增强局部寻优能力,并改进传统的遗传选择操作,保持种群的多样性,提高遗传算法的进化效率。以车间生产计划为实例测试改进算法,并与典型遗传算法的测试结果相比较,验证新算法的可行性与有效性。     

多目标批量生产柔性作业车间优化调度

研究批量生产中以生产周期、最大提前/最大拖后时间、生产成本以及设备利用率指标(机床总负荷和机床最大负荷)为调度目标的柔性作业车间优化调度问题。提出批量生产优化调度策略,建立多目标优化调度模型,结合多种群粒子群搜索与遗传算法的优点提出具有倾向性粒子群搜索的多种群混合算法,以提高搜索效率和搜索质量。仿真结果表明,该模型及算法较目前国内外现有方法更为有效和合理。最后,从现实生产实际出发给出多目标批量生产柔性调度算例,结果可行,可对生产实践起到一定的指导作用。     

基于智能计算方法的AGV制造车间调度问题研究现状

基于智能制造车间物流系统中AGV的复杂动态调度问题,阐述了智能计算方法在复杂调度技术方面及其在智能制造车间AGV调度的研究应用.对群智能计算、遗传算法、人工神经网络等常见智能计算方法的特性及调度问题应用进行分析.针对群智能计算方法重点探究了粒子群算法、蚁群算法及人工蜂群算法在制造业AGV调度中的应用;结合遗传算法与柔性制造系统生产理念总结了AGV调度研究现状;在人工神经网络方法上,介绍了基于深度学习、强化学习有关的AGV调度问题研究及特点.基于智能计算方法各自计算特点对其在制造车间AGV调度应用进行了探讨,总结了智能计算方法在制造车间关于AGV智能调度的研究的发展趋势,方便未来AGV车间调度系统的技术研究选择合适的算法.     

基于智能计算方法的AGV制造车间调度问题研究现状

基于智能制造车间物流系统中AGV的复杂动态调度问题,阐述了智能计算方法在复杂调度技术方面及其在智能制造车间AGV调度的研究应用.对群智能计算、遗传算法、人工神经网络等常见智能计算方法的特性及调度问题应用进行分析.针对群智能计算方法重点探究了粒子群算法、蚁群算法及人工蜂群算法在制造业AGV调度中的应用;结合遗传算法与柔性制造系统生产理念总结了AGV调度研究现状;在人工神经网络方法上,介绍了基于深度学习、强化学习有关的AGV调度问题研究及特点.基于智能计算方法各自计算特点对其在制造车间AGV调度应用进行了探讨,总结了智能计算方法在制造车间关于AGV智能调度的研究的发展趋势,方便未来AGV车间调度系统的技术研究选择合适的算法.     

基于NSGA-Ⅱ算法的液压元件多目标柔性作业调度研究

为解决液压元件制造车间生产调度过程混乱的问题,提出一种基于NSGA-Ⅱ的多目标柔性生产调度优化算法,并建立了相关的数学模型。采用非支配排序和精英储备策略,并设计了算法的编码解码以及交叉、选择和变异的遗传算子。最终通过实例分析,将得出的基于基本加工时间、设备负荷率和生产成本的全局最优解与传统遗传算法优化值进行对比,可见此算法可提高液压制造车间的生产调度效率。     

基于机床加工匹配特性的混合流水车间绿色生产调度

针对混合流水车间绿色生产过程中的设备选择和调度目标匹配问题,提出基于机床加工特性的多目标调度模型和改进遗传算法。该算法建立了混合流水车间调度的时间、能耗与成本优化模型,采用模糊隶属方法描述了机床加工特性,在遗传算法求解过程中通过机床加工特性隶属度与调度目标的权重系数匹配关系,建立了自适应的交叉、变异和优势保留策略,在每一代迭代中提高在调度目标方向上的选择压力,加速收敛。通过实例分析对比了不同算法的优化结果,从而验证了模型及算法的有效性,并提出了高效、节能、经济和综合4种调度生产模式,为混合流水车间绿色生产提供了指导。     

基于元胞机和改进GA的大型零件柔性作业车间调度算法

针对大型零件柔性作业车间调度问题,采用改进遗传算法优化元胞机局部演化规则,提出了元胞机和改进遗传算法相结合的混合调度算法。依据总加工时间最短、各工位负荷率高、同一工位组各工位负荷平衡率高的优化目标,建立了离散化后单个静态调度单元的遗传算法优化模型,并结合算例具体说明了优化过程。通过文献实例演算验证了混合算法求解大型零件柔性作业车间调度问题的可行性和有效性。     

基于改进遗传算法的多目标柔性车间调度问题研究

通过对车间生产调度的特点和算法的研究,建立了离散车间多目标动态调度的数学模型及设计了改进的遗传算法。以最大完工时间最短、总延期时间最小和设备总负荷最小这3个目标作为车间生产优化目标调度模型。利用改进的遗传算法确定车间调度的最优解。最后通过实例分析,验证了算法的可行性。     

The Effects of Scheduling Rules and Routing Flexibility on the Performance of a Random Flexible Manufacturing System

The increased use of flexible manufacturing systems to efficiently provide customers with diversified products has created a significant set of operational challenges for managers. Many issues concerning procedures and policies for the day-to-day operation of these systems still are unresolved. Previous studies in this area have concentrated on various problems by isolating or simplifying the systems under study. The primary objective of this study is to extend previous research by examining the effects of scheduling rules and routing flexibility on the performance of a constrained, random flexible manufacturing system (FMS). Other experimental factors considered are shop load, shop configuration, and system breakdowns. Within the bounds of this experiment, the results indicate that, in the presence of total routing flexibility, the effects of shop load, system breakdowns, and scheduling rules are significantly dampened. In particular, when total routing flexibility exists, the choice of scheduling rules is not critical. We also show that the behavior of scheduling rules in a more constrained FMS environment (i.e., where system breakdowns occur and material handling capability is limited) is consistent with the findings of previous research conducted under less constrained environments. Finally, results indicate that the shop configuration factor has little or no impact on a system's flow-time performance.     

基于MES的生产车间管理信息系统

针对制造企业在实施生产管理信息化过程中存在的问题,提出以制造执行系统(MES)为核心的三层结构———企业资源计划(ERP) /制造执行系统(MES) /过程控制系统(PCS)的生产管理信息化的实施方案,用于解决生产与计划相互脱节的难题,实现了车间的现场调度、生产过程控制、在线质量控制,以及对生产过程中“非常规信息”的控制与管理,加强了制造计划的可执行性。     

Vision-based automated inspection system in computer integrated manufacturing

The industrial application of an automated inspection system that aims to enhance the efficiency and flexibility of a computer integrated manufacturing system (CIMS) is proposed in this paper. A machine-vision-based approach is adopted to utilise its advantages of measurement flexibility, high resolution, and non-destruction. With a closed-loop feedback control architecture, the inspection procedures are fully integrated with the production process to detect and to recover abnormal operations in a real-time mode. Implementation of such a system at a physical shop floor for socket inspection is presented as an example.     

Multi-agent-based fuzzy scheduling for shop floor

This paper deals with a multi-agent architecture of agile manufacturing system and a hybrid strategy for shop floor scheduling. Firstly, it proposes a distributed multi-agent-based manufacturing structure, which has characteristics of self-determination and distribution grounded on multi-agent as well as control and harmony grounded on hierarchical structure or dynamic logical unit. Then, based on the fuzzy theory and method, it studies a hybrid shop floor scheduling strategy that combines fuzzy programming with fuzzy contract net protocol. The hybrid strategy has both virtues of precision of static programming and flexibility of contract net protocol.     

基于双单元制造模式的车间调度控制系统

基于敏捷制造思想研究了离散生产类型的先进制造车间的调度控制系统。在研究双单元制造模式运行和组织特点的基础上，给出了单元重组方法。研究了先进制造车间生产任务管理、生产计划、车间调度、生产运行控制、生产信息管理等问题，提出了以单元动态重组技术为基础的车间生产调度控制系统。     

An integrated scheme for process planning and scheduling in FMS

Process planning and scheduling are the two important manufacturing functions involved in any shop floor activities. As functional integration is essential to realize the benefits of computer integrated manufacturing, a scheme for integration of process planning and scheduling has been introduced in this paper. The proposed scheme can be implemented in a company with existing process planning and scheduling departments when multiple process plans remain available on the shop floor. It consists of two main modules, introduced in detail in this paper. They are process plan selection module and scheduling module.     

Integration of process planning and scheduling in a job shop environment

Today’s manufacturing systems are striving for an integrated manufacturing environment. To achieve truly computer-integrated manufacturing systems (CIMS), the integration of process planning and production scheduling is essential. This paper proposes a framework for integration of process planning with production scheduling in a job shop environment for axisymmetric components. Based on the design specifications of incoming parts, feasible process plans are generated taking into account the real time shop floor status and availability of machine tools. The scheduling strategy prioritizes the machine tools based on cost considerations.     

Multiple-Objective Scheduling for the Hierarchical Control of Flexible Manufacturing Systems

This paper presents a hierarchical approach to scheduling flexible manufacturing systems (FMSs) that pursues multiple performance objectives and considers the process flexibility of incorporating alternative process plans and resources for the required operations. The scheduling problem is solved at two levels: the shop level and the manufacturing system level. The shop level controller employs a combined priority index developed in this research to rank shop production orders in meeting multiple scheduling objectives. To overcome dimensional complexity and keep a low level of work-in-process inventory, the shop controller first selects up to three production orders with the highest ranking as candidates and generates all possible release sequences for them, with or without multitasking. These sequences are conveyed to the manufacturing system controller, who then performs detailed scheduling of the machines in the FMS using a fixed priority heuristic for routing parts of multiple types while considering alternative process plans and resources for the operations. The FMS controller provides feedback to the shop controller with a set of suggested detailed schedules and projected order completion times. On receiving these results, the shop controller further evaluates each candidate schedule using a multiple-objective function and selects the best schedule for execution. This allows multiple performance objectives of an FMS to be achieved by the integrated hierarchical scheduling approach.     

分段式车间作业调度算法

车间作业调度问题是制造系统运筹技术、管理技术与优化技术发展的核心。本文对离散作业型 (Job Shop)车间中的作业调度问题做了探讨 ,并根据离散作业调度的阶段性提出了基于作业状态空间的逐段式车间作业调度算法。通过对一个实际车间作业调度仿真比较 ,此算法运算速度比最短加工时间 (SPT)和最少工作量剩余 (L WR)算法快 ,其调度结果具有可执行性     

基于过程集成的闭环动态工艺规划系统

描述了一个在过程上实现工艺规划与车间规划集成的闭环动态工艺规划系统,建立了实用化CAPP系统的新模型,丰富了动态CAPP的概念。它能根据车间环境的状态,充分利用制造工艺和车间环境的柔性产生优化的工艺方案。系统在车间环境约束下采用专家系统技术进行非线性工艺规划,产生可选工艺路线和工序可选设备。在一个由工艺路线选择、设备动态优化选择和车间优化规划构成的闭环系统中,以高生产效率为目标,根据推广的关键路线分析的结果和一系列启发式知识动态地选择工艺路线和设备,最后获得有较高实践意义的结果。