基于蚁群算法的中小手工制造企业人员调度

根据多品种、变批量的插单式生产的复杂特性,利用集群智能这种复杂系统建模手段研究中小企业生产线组建和人力资源调度过程。在将离散的生产单元运行特点与蚁群劳动分工模型进行对比分析的基础上,根据生产任务的要求和各个生产单元的负载不同重新设计工人的属性特征和员工间调配方案,实现了由计算机自动控制的自适应劳动分工模型。实验表明数字仿真结果大致与实际情况吻合。运行结果体现了非流水线手工作业生产中的劳动力分配的自组织自适应特征。     

基于FLEXSIM的流水线生产物流优化

在根据生产物流的特点及其仿真技术的功能,提出了生产物流仿真优化的两个重要问题,阐明了利用FLEXSIM软件对流水线生产物流仿真优化的方法,并利用一个工厂四条流水线生产物流进行仿真优化的例子,说明了基于FLEXSIM软件对流水线生产物流优化过程.     

面向船体曲面分段建造的虚拟流水线生产调度

基于船舶船体曲面分段建造的特点,利用成组技术和流水线生产的原理,提出了面向曲面分段建造的虚拟流水线生产模式,研究了包括生产组织改造和生产调度的关键技术。根据虚拟流水线生产模式的原理,建立作业班组分解模型,并应用遗传算法实现基于虚拟流水线的曲面分段制造生产调度方法。利用上海某造船厂实际数据进行验证,结果表明虚拟流水线生产模式及方法可有效提高船舶生产效率。     

一类零缓冲可中断流水线调度优化方法

针对具有多种平面分段的流水线调度中存在的拖期、流水线闲置和生产效率低等问题,构建零缓冲可中断流水线的调度模型。以分段总完工时间最短及最小延期交货惩罚为目标,同时考虑分段的排序、流水线选择情况,利用运筹学方法建立平面分段流水线调度问题的非线性整数规划模型。在此基础上,结合某船厂实际数据通过实验验证了模型的有效性。将该优化模型调度结果与SPT、EDD、WSPT、FCFS四种调度规则下的结果进行对比,结果表明：该优化模型调度得到的总完工时间最短,且延期交货惩罚最小。     

基于Plant Simulation的智能制造测试床仿真模型 设计与应用

为了验证智能制造测试床的整体布局设计和制造工艺在生产运营环境下的合理性，利用西门子Plant Simulation工厂仿真软件进行生产节拍和设备利用率分析。首先，建立了按订单生产运行的制造生产线二维仿真模型，根据生产要求对二维仿真模型进行输入参数设定，并根据二维仿真模型运行后得到的分析统计结果进行工艺布局、物流布局和制造策略的优化。然后，在二维仿真模型基础上，为了让仿真模型在建设阶段和运营阶段具有更直观的展示效果，基于原三维设计图，在三维仿真模型中替换或导入各对象的三维模型，并运用Simltalk语言编写精细的三维位置坐标和动作路径动画程序，对仿真模型进行三维效果优化。结果表明优化后的智能制造测试床三维仿真模型可以实现与实际生产一致的业务运行模式，它具有更形象、逼真的动态运行展示效果。仿真结果可指导智能制造测试床的建设与优化，且在测试床投入运营后，仿真模型还能够接受运营数据以对测试床进行持续迭代的优化。提出的仿真模型设计方法为实现智能制造测试床的“数字孪生”奠定了基础。     

面向置换流水车间生产过程的瞬态产能计算方法

针对具有可重入环节的置换流水车间易发生堵塞、生产布局规划难等情况，受伯努利理论启发，分析了此置换流水车间的生产流程，建立基于瞬时状态概率的系统生产过程性能预测模型。首先，根据加工任务多样性和生产工艺可靠性，定义人机混合加工机器的状态表达函数以及可靠性模型，并利用瞬态跃迁描述模型中的算子，建立瞬态产能模型，对置换流水车间的映射关系进行解析。其次，通过状态函数定义并计算加工机器和缓冲区的状态，对置换流水车间进行逆向建模。最后，根据实际生产情况设置相应生产参数并进行实验仿真。仿真结果证明，该模型具备可行性，能够为实际具有可重入环节的置换流水车间中的布局优化和高效运行提供理论支撑。     

基于虚拟流水线的曲面分段制造系统建模与调度

结合船舶生产模式的特点,提出了船舶曲面分段加工的虚拟流水线作业模式.根据虚拟流水线生产的原理,利用遗传算法研究基于虚拟流水线的曲面分段制造生产调度问题,并结合Petri网进行模拟仿真,搭建了Petri网与遗传算法相结合的虚拟流水线生产调度系统框架.实验结果表明,虚拟流水线生产模式可有效提高船舶生产效率.     

平行辊矫直机压下量选择及矫直力计算

利用弯曲变形理论对平行辊矫直机压下量和矫直力的计算方法进行了研究,并模拟实际生产情况,进行仿真计算,计算结果接近于生产实际,可用于指导生产实践和设计工作。     

多产品串并联连续生产系统主生产计划方法

某些生产过程包含了若干连续生产的流水线,其中一些是并行的,而有一些于另外一些是串行的.因此,构成了一个串并联生产系统.在多产品生产的情况下,其主生产计划问题变得非常复杂.针对这种情况,提出了将MRP与JIT相结合的解决方案.根据该方案思想建立了主生产计划模型,并采用遗传算法求解.仿真结果表明,该方案效果良好.     

基于事件序列图方法的供应链建模与分析

介绍了事件序列图的概念及基本图符,提出了基于事件序列图的供应链建模方法,给出了其建模步骤,并结合示例说明该方法的建模过程.讨论了模型的应用情况,对供应链的速度、成本、资源利用率等性能测度进行定义.最后,运用蒙特卡罗仿真方法对模型模拟运行并对结果进行分析.     

装配线仿真流程及其案例研究

针对目前装配线仿真研究缺少模型检验步骤而导致仿真结果不可信的问题,在总结目前装配线仿真研究的基础上,引入两次仿真模型有效性的检验过程,提出完整的装配线仿真流程。为验证该流程的有效性,以实际装配线为例,在分析布局与工艺流程的基础上,考虑物流线布局、瓶颈机器数量、AGV数量和AGV速度对产能的影响,设计并基于Plant Simulation软件建立24种方案。所有方案仿真模型有效性的检验通过后,通过比较各方案的产能与机器利用率得到最佳方案。仿真结果表明,优化后的产能较初始方案提升约227%,瓶颈机器利用率提升约51%,平均机器利用率提升约121%。所提仿真优化流程可行且有效,可为装配线仿真研究与应用提供指导,对其他生产领域的仿真研究也具有借鉴意义。     

基于精益思想的生产线改造仿真与研究

阐述了企业生产线改造过程中精益思想应用的必要性,以及在生产线改造中需要遵循的精益原则:生产线平衡、连续流、产品混流生产和标准化管理。以水洗机为实例,分析了水洗机装配生产线的现状,基于传统思想与精益思想,使用面向对象的eM-Plant软件,建立相应的离散事件仿真模型,以产量、在制品和对市场的反应速度为绩效指标,研究和分析模型仿真进行的输出结果,对两种不同思想的生产线改造进行比较,为装配生产线实际改造提供依据。     

基于标准作业时间和仿真的装配线规划

在分析装配线规划内容的基础上,提出了基于标准作业时间及系统仿真的装配线规划方法并开发了相应的原型系统。通过建立装配操作树,定义装配操作约束,规划合理平衡的装配工位,同时生成装配作业表。以此作业表为输入,建立装配线的仿真模型,为装配线系统布置中的流参数等优化提供环境。通过这些工作,为企业制定工时定额合理的装配线,提高自主规划生产系统的能力提供途径。     

Labour productivity in modular assembly: a study of automotive module suppliers

Modular assembly is being applied to an increasing number of vehicles and part manufacturers to manage the ever-changing demands of the automotive industry. In spite of many researches performed on the supply chain management and logistics aspects of modular production, there is no research discussing modular production line concepts used by module suppliers. In this paper, labour productivity of two assembly line concepts including the conveyor line and box assembly line is studied under modular production environment. Both line concepts and respective assembly processes are described in detail. Mathematical models showing the total work faced by these two assembly line concepts are developed and compared. Two productivity scales are defined: the maximum achievable productivity and the actual productivity. The labour productivity rates of these assembly line concepts on above productivity scales obtained from calculations and a simulation are compared as a performance measure.     

Scheduling of smart intra – factory material supply operations using mobile robots

This paper presents the design and prototype implementation of a service-based control system responsible for the material supply operations planning and coordination in assembly lines. The material supply processes are carried out by autonomous mobile units that are responsible for the transportation of the consumables from the warehouse to the production stations. The plan generation based on time and inventory level driven criteria is automatically carried out by a web-based software that can also distribute the derived plan to the autonomous mobile units. The proposed system was implemented on a case inspired by an actual production line from the automotive assembly sector. Discrete event simulation has been employed for the investigated production system, to derive the specifications for the mobile units (e.g. number of boxes that can carry simultaneously) that may serve the system efficiently. The results indicate that the proposed architecture integrated with the discussed mobile assistant units may provide high quality solutions with respect to the end user criteria.     

Mixed model assembly system with multiple secondary feeder lines: layout design and balancing procedure for ATO environment

The constant research for efficiency and flexibility has forced assembly systems to change from simple/single assembly lines to mixed model assembly lines, while the necessity to reduce inventory has led the transition from single to multi-line systems, where some components are assembled in secondary lines, called feeder lines, connected to the main one by a ‘pull philosophy’. A possible approach to configure such an assembly system is to balance the main line first and use the retrieved cycle time to balance each feeder line separately, which is a questionable solution, especially if operators can perform tasks on both the feeder and the main line. Moreover for its complexity the mixed model balancing problem is usually solved transforming it into a single model by creating a single ‘virtual average model’, representative of the whole production mix. The use of a virtual average model assumes that the processing times of some models are higher or lower than the cycle time, which creates overload/idle time at the stations. This approach, especially in complex multi line production systems, largely reduces the assembly line productivity and increases the buffers dimensions. This paper faces the mixed model assembly line balancing problem in the presence of multiple feeder lines, introducing an innovative integrated main-feeder lines balancing procedure in case of unpaced assembly systems. The proposed approach is compared with the classical one and validated through simulation and industrial applications.     

A multi-decision genetic approach for workload balancing of mixed-model U-shaped assembly line systems

A mixed-model assembly line is a type of production line where a variety of product models similar in product characteristics are produced. As a consequence of introducing the just-in-time (JIT) production principle, it has been recognised that a U-shaped assembly line system offers several benefits over the traditional straight line system. This paper proposes a new evolutionary approach to deal with workload balancing problems in mixed-model U-shaped lines. The proposed method is based on the multi-decision of an amelioration structure to improve a variation of the workload. This paper considers both the traditional straight line system and the U-shaped assembly line, and is thus an unbiased examination of line efficiency. The performance criteria considered are the number of workstations (the line efficiency) and the variation of workload, simultaneously. The results of experiments enhanced the decision process during multi-model assembly line system production; thus, it is therefore suitable for the augmentation of line efficiency in workstation integration and simultaneously enhancement of the variation of the workload. A case study is examined as a validity check in collaboration with a manufacturing company.     

Optimising and simulating the assembly line balancing problem in a motorcycle manufacturing company: a case study

In this paper, we present a real life assembly line balancing problem for a motorcycle manufacturing company. Results from the initial situation in the company are compared to those provided by a heuristic method and by a novel neighbourhood search method. An ARENA simulation model is developed to test the different proposals. The model was validated by comparing the simulation results from the initial company scenario with the real operation results. Consequently, the extension to the developed proposals allows us to select an adequate assembly line for the company, resulting in a greater productivity level and a more balanced line with respect to the operation times in the stations and the activity of the workers. The company has subsequently implemented our proposed schedule, obtaining remarkable improvements in its productivity.     

发动机装配线关键工位物料动态配送方法

目的 为降低装配车间线边物料配送及库存管理成本,提高配送环节对生产节拍变动的适应性,设计一种针对关键工位重点物料的动态配送方法.方法 首先,采用K-means算法考虑物料价值、包装体积、通用性进行初步分类,结合需求变异系数确定出关键工位重点物料;其次,结合发动机装配线生产特点,设计基于动态配送时间和数量的物料配送方法,并建立包括运输成本和线边库存成本的配送总成本模型;最后,通过Flexsim软件搭建生产物流仿真模型,分别模拟Z车间现有配送方法和所设计方法进行对比验证.结果 实行动态配送后,重点物料的平均库存容量和持有库存成本均得到有效降低,最大降幅分别为23.91％和23.96％.结论 结果表明所提方法能够提高车间物料管理的针对性,降低总配送成本,提升配送系统的柔性化.     

An optimisation support for the design of hybrid production lines including assembly and disassembly tasks

The optimisation problems related to the assignment of tasks to workstations in assembly and disassembly lines have been largely discussed in the literature. They are known, respectively, as Assembly Line Balancing and Disassembly Line Balancing Problems. In this study, both types of task performed on the identical product are integrated in a common hybrid production system. Therefore, the logistic process is simplified and disassembly tasks can supply easier the assembly tasks with the required components. The considered production system has the layout of two parallel lines with common workstations. The product flow is conventional in the assembly line and reverse in the disassembly line. The paper provides a new mathematical model for designing such a hybrid system and an approximate approach based on ant colony optimisation for solving large-scale instances. The solution method is tested in a case study. The obtained results are compared with the solution provided by the design of two independent lines. The analysis of the results highlights the potential benefits of the hybrid production system.