考虑设备多状态的缸盖生产线性能分析与优化

为实现发动机缸盖生产线的性能提升和成本管控,提出一种考虑设备多状态的发动机缸盖生产线性能分析与缓冲区配置优化方法。首先,采用马尔可夫模型揭示设备多状态与缓冲区库存的变化规律,建立了生产线可用度与缓冲区容量的耦合模型。其次,构建了以生产线可用度和缓冲区配置成本为目标的多目标优化模型,并采用NSGA-Ⅱ算法求解优化模型。最后,通过案例证明所提方法能提高缸盖生产线的生产性能并降低缓存区配置成本。     

基于遗传算法的机器人自动化生产线缓冲区容量分配方法

研究一种机器人自动化生产线缓冲区容量分配问题的优化方法。生产系统的生产率与各工序可靠性、生产率及缓冲区容量密切相关。生产线缓冲区总量受限,须将此总量分配至各生产工序的缓冲区。采用连续型生产线模型,并使用近似和分解方法建立生产线可用度和缓冲区容量分配间的关系模型。提出在缓冲区总容量受限状态下,以生产线最大可用度为目标的优化策略。设计半父体比例交叉和单亲交叉型变异的遗传算法得到缓冲区容量分配的次优解,并将该方法应用于一种2平动自由度高速并联机械手为核心的输液软袋装箱码垛自动化生产线,得到该类生产线的缓冲区分配优化方案。多条机器人装箱码垛生产线运行结果表明,此方法是行之有效的。     

配置有限缓冲区的缸体生产线平衡优化

针对多工序生产线出现的不平衡问题,优化合理的缓冲区配置将是有效解决途径之一。文中基于双工位单缓冲区分解方法,将多工序生产线分为多个连续子系统,并建立最小化工件平均生产加工时间优化目标模型。采用模拟退火算法求解优化模型,得到各工位间的缓冲区容量配置。最后本文以柴油发动机缸体U型加工生产线为研究对象,并运用Plantsim仿真进行方法有效性验证。     

基于Plant Simulation的柴油机缸体生产线仿真与配置优化

针对某柴油机缸体生产线设备利用率不足和生产效率低的问题,借助Plant Simulation软件建立该生产线的仿真模型,分析生产线的运行情况,并获得生产线设备利用率、生产率等信息。然后,利用遗传算法,对各个缓冲区的容量进行优化。最后,根据仿真结果与生产线实际状况,采用在第一、第二瓶颈工序分别配置容量为19和3的缓冲区,并安排线外机床定期清理缓冲区积压工件的优化方案。研究结果表明,所提出的优化方案可以将设备的平均利用率和生产线的生产率分别提高3. 4%和9. 4%。该研究可以为优化生产线提供指导,减少企业资源的浪费。     

可重组制造系统缓冲区容量的优化研究

为了确定可重组制造系统中的缓冲区容量,通过分析机床工作状态、生产需求量等因素对缓冲区容量的影响,建立了缓冲区状态数学模型.在此基础上,提出了缓冲区容量、机床可用度和任务需求率之间的函数关系.以满足生产任务为前提,将重组后加工域缓冲区容量最小化作为优化目标.通过粒子群优化算法,利用非可微精确罚函数法处理约束条件,采用可变惯性权重平衡搜索,以求得各工序间缓冲区容量.最后结合仿真实例,探讨了该生产线重组后系统缓冲区容量的最优配置.     

基于可用度评价的混联生产线缓冲区配置优化

为快速有效地分配缓冲区容量,提高混联生产线的可用度和生产率,提出了一种基于可用度评价的缓冲区分配方法。在考虑混联生产线特性的同时,通过分析设备状态与缓冲区状态之间的转化规律,将缓冲区进行等效处理,以获得等效设备的可用度;结合通用发生函数(UGF)法,建立混联生产线的可用度与缓冲区容量关系的数学模型,以整线可用度最大为目标,利用遗传算法(GA)求解得到最优的缓冲区配置策略。多个生产线实例缓冲区优化分配结果表明,基于可用度评价的缓冲区分配方法能够在有效解决缓冲区配置问题的同时,明显减少生产线的平均在制品数量。     

环形生产线缓冲区配置及设备布局集成优化

研究了缓冲区配置及设备布局模型,结合环形生产线构型特征,分析线上缓冲区配置与设备布局的关联,提取共同约束条件及物流路径长度、生产率、托盘数等关键生产线评价指标作为目标函数,建立缓冲区配置及设备布局集成优化模型,并利用NSGA-II进行多目标求解。经过实例验证,该方法具有有效性。     

一类装配支线缓冲区配置的两阶段求解方法研究

研究一类装配支线的物料输送与缓冲问题,论文将传送辊道作为缓冲区的补充,构建基于辊道-缓冲区满足总装线产出率且最小化装配支线缓冲区总容量的优化模型.考虑到装配支线缓冲区容量配置与总线产出率之间不存在解析解,且装配支线缓冲区总容量一定时工位间不同缓冲区配置也影响着总线的生产.提出一种两阶段求解算法:第一阶段,采用遗传算法求解支线有限缓冲区总容量下的总装线最大产出率;第二阶段,根据Gershwin关于缓冲区-产出率的研究理论,获得总装线产出率所对应的装配支线缓冲区总容量,并进行支线缓冲区容量的合理分配.最后,通过案例分析验证该方法的有效性.     

基于多阶段批调度的混合型生产过程的建模与优化

根据混合型生产过程生产方式复杂的特点,采取分阶段的批调度方法建立模型,并且在模型中充分考虑了中间缓冲区的库存容量、生产线的加工容量以及客户的交货期等约束条件,在此基础上达到最低生产成本和最短的加工时间的多重调度目标。同时构造了基于该模型的启发式算法,降低运算速率、提高结果的准确度,从而使得该调度模型以能够得到最优的生产调度方案。实例仿真结果表明了该模型的可行性,同时为制造企业提供了一种有效的决策手段。     

快速重组制造系统的动态建模和结构体系

提出了基于组态式柔性制造单元组成的阵列式布局的快速重组制造一系统的创新结构 体系,建立了以生产效益为该系统设计和运行决策目标的随机模型,应用排队网络模型静态马洋科夫工件运送方式得出系统重组时缓冲区容量的优化配置和最优工件运送策略的算法,     

Comparative Evaluations of Buffer Allocation Strategies in a Serial Production Line

The problem of allocating buffer storage to serial production lines so as to maximise steady-state throughput is considered. Some researchers have previously developed rules of thumb for the optimum allocation of a given total amount of buffer space to maximise the throughput of a production line. In this paper, a modified buffer allocation strategy based on the Lin & Lin’s rule, is suggested, and it is compared with three other existing strategies. Some recommendations are made on how to select a buffer allocation strategy. In addition, a buffer utilisation-based search method, which is a methodology to increase the throughput of a production line, is suggested.     

Buffer allocation in unreliable production lines based on design of experiments, simulation, and genetic algorithm

This paper presents a multiobjective formulation of the buffer allocation problem in unreliable production lines. Majority of the solution methods for buffer allocation problems assume that the process times, time between failures, and repair times are deterministic or exponentially distributed. This paper relaxes these restrictions by proposing a simulation-based methodology which can consider general function distributions for all parameters of production lines. Factorial design has been used to build a meta-model for estimating production rate based on a detailed, discrete event simulation model. We use genetic algorithm combined to line search method to solve the multiobjective model and determining the optimal (or near optimal) size of each buffer storage.     

串行连续生产线的缓冲库存控制与可靠性研究

以可靠性理论为基础,建立了单元化的串行连续生产线模型,为保证连续生产的可靠性,研究了缓冲库存最小安全量的计算,同时研究了缓冲库存的补给,提出了非均匀节拍法,可有效保障安全库存量,具有一定的应用价值。对生产线的整体可靠度进行了研究,得到了其可靠性计算公式,从中可知生产的可靠性与设备故障率、修复率、缓冲库存量、生产节拍和时间相关。在最小成本原则基础上,提出了生产单元可靠度、设备故障率与维修率的设计方法,可供参考。     

Optimal buffer allocation in a multicell system

Motivated by a layout design problem in the electronics industry, we study in this article the allocation of buffer space among a set of cells. Each cell processes a given part family and has its own revenue-cost structure. The objective of the optimal allocation is to maximize the net profit function (total production profits minus total buffer allocation costs). According to the flow pattern of jobs, the cells are categorized into two types. A type 1 cell is modeled as a Jackson network; a type 2 cell is modeled as an ordered-entry system with heterogeneous servers. Both models have finite waiting room, due to the buffer capacity allocated to the cells. We show that under quite general conditions, the production rate of each cell of either type is an incresing and concave function of its buffer allocation. Exploiting this property, a marginal allocation scheme efficiently solves the optimal buffer allocation problem under increasing concave production profits and convex buffer space costs.     

虚拟制造环境下轿车白车身装焊线建模与仿真研究

在虚拟制造环境下，集成微观的制造工艺内容和宏观的离散事件系统2个层次，建立了典型白车身装焊线数字模型，实现了在计算机上对实际生产景况的三维直观表达。以此数字模型为基础，结合系统仿真技术和具体的寻优算法，针对兼顾成本和效率的目标函数，进行装焊生产线缓冲区优化设计等方面的研究。     

An integrated allocation method for the PCB assembly line balancing problem with nozzle changes

There are several placement machines connected by a conveyor in a printed circuit board assembly line. The objective of the line balancing problem is to minimize the cycle time of the assembly line, which is the maximum production time of the placement machines. In this paper, the nozzle factor, which is often ignored, is considered in estimating the production time of the placement machine, and the nozzle change is also allowed. The production time of a machine is a linear function of the number of components, the number of turns and the number of nozzle changes performed by the machine, which are determined by the component allocation problem, the nozzle set allocation problem and the head allocation problem. These three allocation problems compose the line balancing problem and are solved iteratively. First, the component allocation problem is solved by proposed genetic algorithms (GAs), which generate feasible allocation solutions directly. To search efficiently, non-selective and selective allocation strategies are proposed to solve the component allocation problem. A greedy heuristic (GH) is proposed to solve the nozzle set allocation problem and the head allocation problem simultaneously. Then, the GAs for the component allocation and the GH for the nozzle set and head allocation are integrated according to their interactive relations. Finally, the efficiency of the composite algorithm is illustrated by numerical analysis.     

Product Grouping and Resource Allocation in Multiline Manufacturing Systems

This paper studies the product grouping problem and the resource allocation problem in the design of manufacturing systems where multiple production lines are used to manufacture a range of products. Each production line in the product grouping problem is dedicated to manufacturing a group of products. A mathematical model is developed to determine the number of product groups and the composition of each product group in the manufacturing system. For the resource allocation problem, a mathematical model is developed to determine the optimal resource allocation scheme for each production line and the optimal inventory level for each product. A genetic-based algorithm is proposed to solve the product grouping problem and the resource allocation problem simultaneously, and its results are compared to those of the conventional heuristic approaches. The proposed genetic approach is a simple but effective means of solving these problems.     

典型线路下重载机车胶泥缓冲器泄漏故障分析

针对典型线路下重载机车使用的缓冲器QKX100出现的胶泥泄漏现象,使用铁科院纵向动力学计算软件进行典型线路下重载货运列车的纵向动力学计算;结合胶泥芯子的结构原理,分析钩缓系统故障产生的原因。分析结果表明:在持续的陡坡线路上,变坡度会引起车钩力的剧烈变化,而在进行循环制动时,列车的中后部出现较大纵向冲动;而在此种线路条件下,QKX100弹性胶泥缓冲器的作用也越频繁,因此缓冲器动密封圈的磨损就会加大,胶泥泄漏的也就越大。为了改善缓冲器工作状态,应采用适当的机车操作、合理的列车编组以及更严格的缓冲器生产管控。