面向多品种变批量的可重构制造系统的设计方法研究

可重构制造系统的设计目标是要确定各种零件的生产周期、各种零件之间的生产顺序与加工各种零件所用的组态。建立了各生产周期成本模型、重构成本模型与全生产周期成本模型。由各种零件的批量确定加工各种零件的标准生产周期，分析系统成本冗余，得到了多组偏差生产周期，求出了各种生产周期下各种零件之间所有生产排序的K-优组态路径。通过比较所求得的组态路径，可以获得一条最优与多条次优组态路径。用案例验证了所提出的方法。     

可重构制造系统工艺路线与系统布局设计研究

为使可重构制造系统的重构过程更加快速有效,提出了一种工艺路线和系统布局设计的方法.首先,基于图论构建了可重构制造系统工艺路线的有向网络模型,并采用Dijkstra算法和双向扫视算法,进行最优工艺路线和备选工艺路线的选择;然后,以工艺路线为基础,依据排队论中的相关理论,对制造系统的布局进行优化设计,以获得可重构制造系统布局方案.实例表明,该设计能够适应可重构制造系统快速多变的特征,提高对制造系统已有资源的利用率.     

双零件族随机环境下可重构制造系统的生产能力设计

基于概率论、排队论与更新理论的方法,建立了双零件族随机市场需求模型与可重构制造系统的排队控制模型.以可重构制造系统的生产能力与开机数量为参数,基于重构成本、制造系统折旧成本与仓储成本,构建了平稳条件下可重构制造系统长期运行时,单位时间内所取得的平均利润优化模型,并提出了优化方法与步骤.通过求解该模型,得到了可重构制造系统的最优生产能力与最佳开机数量.基于求得的最优生产能力与最佳开机数量,给出了可重构制造系统的订单接受率与切换周期等性能指标.最后,用案例验证了所提方法的可行性.     

基于图论的可重构制造系统单零件流水线构形优化

获取各生产周期内的最优和K-1个次优(K优)单零件流水线构形,是可重构制造系统构形选择中一个重要的优化问题。给定零件的工序优先图、工序和工位操作的关系以及各工位操作的可选设备,该流水线构形优化问题即确定工作站数量,选择各工作站内的机床类型和数量,选择并分配工位操作,以最小化流水线构形的资本成本。将寻求满足功能和产能约束、空间约束和投资限制的K优构形问题建模为关联所有可行工位操作序列的复合增广有向图上的约束K最短路径问题,获得K优解。最后,通过案例研究验证了该方法的有效性和优越性。     

基于遗传算法的可重构制造系统多零件流水线构形优化

获取各生产周期内的最优和K-1个次优(K优)多零件流水线构形是可重构制造系统运行阶段的一个重要优化问题.给定各零件的工序优先图、工序和工位操作的关系以及各工位操作的町选设备,多零件流水线构形优化问题即为确定工作站数量、各工作站内并列放置机床的类型和数量以及选择和分配各零件的工位操作,以最小化构形的资本成本.为获得K优构形,首先放宽现有模型对上位操作分配的限制,建立了构形优化问题的0-1非线性规划模型,扩展了可行解空间.随后提出一种面向可行工位操作分配的遗传算法,从可行解空间中快速获取K优解.案例研究表明,该方法能获得优于现有模型最优解的解,同时也验证了所建模型和优化方法的有效性.     

仿真环境下RMS设施布局分析研究

可重构制造系统(RMS)设施布局问题是一个重要而复杂的研究课题,对制造系统的性能有很大的影响。首先在综合考虑系统复杂性特点的基础上,构建了相应的成本数学模型。然后基于产品种类、生产批量和订货提前期这三个方面的市场需求特征,对RMS布局重构策略进行分析,并构建了仿真框架和仿真流程。最后通过案例分析,验证了该分析方法的可行性和有效性,为RMS布局重构提供了决策依据。     

面向可重构制造系统的重构导向动态机会维护策略

为快速响应市场需求的变化,可重构制造成为烟草加工企业生产制造的未来发展模式.针对烟草企业在可重构制造模式下的维护策略,提出了面向可重构制造的动态维护时间窗策略.采用多层级建模架构,在设备层研究不同类型设备的健康演化趋势,实时输出各台设备的预知维护周期;基于设备层输出,在系统重构和构形扩展机制方面,分析构形更新对系统维护优化的影响,进行决策集合重构建立;在系统层,以新构形所含设备层维护周期和结构分析作为系统层维护优化调度的输入,决策输出系统层维护调度方案,并动态反馈给各设备进行下一周期的维护规划.算例分析表明,提出的动态维护时间窗策略可实现快速决策响应和成本显著降低.     

可重构制造:模式、系统及关键技术

全球经济一体化,要求制造系统能够满足多品种、变批量的市场需求。面向产品族设计的可重构制造系统,兼顾了数控加工中心的柔性强和刚性生产线效率高的优点,同时具有良好的经济性,是满足大批量定制要求的最佳模式。可重构制造技术包括产品可重构、工艺可重构、制造装备可重构和生产系统可重构等四个层面。可重构制造系统的设计,无论是在设备层、还是在系统层,都需要采用模块化的结构设计思想,以及基于总线技术和开放式控制原理的监测与控制设计。对可重构制造系统的建模评价,需要从全寿命周期对系统的重构时间与重构成本,系统的可转换性、开放性与可诊断性,模块的可集成性与系统的可靠性等方面,进行综合建模与评价。     

可重构制造系统重构方案的综合评价方法

可重构制造系统需要根据生产任务的变化进行自身重构,为系统客观地评价重构方案,建立了可重构制造系统重构方案的综合评价模型。首先,对可重构制造系统的实际情况进行研究,提出一种重构方案的评价指标体系,考虑到决策者的主观性,利用层次分析法确定各指标的权重系数,再利用灰色关联分析法对各个重构方案进行定量评判,确定各个重构方案与理想方案的接近程度,并对其进行优劣排序,为决策者选取最优方案提供科学、有效的方法。以某企业的重构生产线为实例,验证了该方法的有效性和可行性。     

可重构制造系统概述

总结了国内外学者对于可重构制造系统（RMS）及相关领域的研究,归纳得出RMS的特性及关键技术,简要阐述RMS是如何应对市场的突然变化。利用层次分析法对大规模生产系统（DMS）、柔性制造系统（FMS）及RMS等3个典型的制造系统进行评价,验证其在制造系统发展中的优势地位。     

Graph theory-based approach to optimize single-product flow-line configurations of RMS

Generating economical and distinctive configurations for a given demand period is an important optimization problem for reconfigurable manufacturing systems (RMS) at both initial design and reconfiguration stages. This paper presents a graph model to optimize capital cost of singe-product flow-line (SPFL) configurations of RMS. The parameters of the SPFL configuration include number of workstations, number and type of machines and assigned operations for each workstation. The full topological sorting and graph augmentation procedures are developed to derive a combined machine graph from the operation precedence graph of a specific product. Then a two-phase optimization approach is proposed. In the first phase, the optimal and K-1 suboptimal configurations are generated by solving a constrained K-shortest paths problem on the machine graph. In the second phase, a dissimilarity index is introduced to measure the dissimilarity between every pair of found configurations. Subsequently p distinctive ones out of K configurations are obtained using the algorithms for p-dispersion problem. Case studies illustrate the effectiveness of our approach and show some superiority of our approach compared to existing approaches. Computational experience shows that the approach is fit for small-to-medium size problems of configuration generation. The approach is also applied to optimizing SPFL in mechanical production.     

最低成本工艺的DIJKSTRA优化法及其CAD

运用Ｄｉｊｋｓｔｒａ算法，对机械加工工艺的生产费用进行了优化设计，得到了最低生产费用条件下的最优加工工艺路线与加工方法。给出了计算机算法实例。     

Investigating optimal capacity scalability scheduling in a reconfigurable manufacturing system

Responsiveness to dynamic market changes in a cost-effective manner is becoming a key success factor for any manufacturing system in today’s global economy. Reconfigurable manufacturing systems (RMSs) have been introduced to react quickly and effectively to such competitive market demands through modular and scalable design of the manufacturing system on the system level, as well as on the machine components’ level. This paper investigates how RMSs can manage their capacity scalability on the system level in a cost-effective manner. An approach for modeling capacity scalability is proposed, which, unlike earlier approaches, does not assume that the capacity scalability is simply a function of fixed increments of capacity units. Based on the model, a computer tool that utilizes a genetic algorithm optimization technique is developed. The tool aids the systems’ designers in deciding when to reconfigure the system in order to scale the capacity and by how much to scale it in order to meet the market demand in a cost-effective way. The results showed that, in terms of cost, the optimal capacity scalability schedules in an RMS are superior to both the exact demand capacity scalability approach and the approach of supplying all required capacity at the beginning of the planning period, which is adopted by flexible manufacturing systems (FMSs). The results also suggest that the cost-effective implementation of an RMS can be realized through decreasing the cost of reconfiguration of these new systems.     

A staged algorithm to determine production lot size and delivery period for long-term production plan

This study submits a mathematical model called the optimal production lot size (OPLS) model to reach the optimal design of a network-type production system for long-term production undergoing the limitation of finite machines of each machine type. This study not only discusses the production rate, the production lot size, the production period, the machine cost, and the number of machines for each workstation into the objective, but develops an efficient step-by-step algorithm, staged algorithm, with the combinatorial applications of the maximal flow problem and the shortest route method to optimize the system profit. Additionally, the detailed procedure of searching the optimal solution is presented by a numerical example. This paper indeed contributes the applicable scheme to the design of a network-type production system for the long-term manufacturing, and provides the optimal production lot size and period for the production planners in today's manufacturing industry with profound insight     

Cooperative optimization of reconfigurable machine tool configurations and production process plan

The production process plan design and configurations of reconfigurable machine tool (RMT) interact with each other. Reasonable process plans with suitable configurations of RMT help to improve product quality and reduce production cost. Therefore, a cooperative strategy is needed to concurrently solve the above issue. In this paper, the cooperative optimization model for RMT configurations and production process plan is presented. Its objectives take into account both impacts of process and configuration. Moreover, a novel genetic algorithm is also developed to provide optimal or near-optimal solutions: firstly, its chromosome is redesigned which is composed of three parts, operations, process plan and configurations of RMTs, respectively; secondly, its new selection, crossover and mutation operators are also developed to deal with the process constraints from operation processes (OP) graph, otherwise these operators could generate illegal solutions violating the limits; eventually the optimal configurations for RMT under optimal process plan design can be obtained. At last, a manufacturing line case is applied which is composed of three RMTs. It is shown from the case that the optimal process plan and configurations of RMT are concurrently obtained, and the production cost decreases 6.28% and nonmonetary performance increases 22%. The proposed method can figure out both RMT configurations and production process, improve production capacity, functions and equipment utilization for RMT.     

Production planning and performance optimization of reconfigurable manufacturing systems using genetic algorithm

To stay competitive in the new dynamic market having large fluctuations in product demand, manufacturing companies must use systems that not only produce their goods with high productivity but also allow for rapid response to market changes. Reconfigurable manufacturing system (RMS) is a new paradigm that enables manufacturing systems to respond quickly and cost effectively to market demand. In other words, RMS is a system designed from the outset, for rapid changes in both hardware and software components, in order to quickly adjust its production capacity to fluctuations in market demand and adapt its functionality to new products. The effectiveness of an RMS depends on implementing its key characteristics and capabilities in the design as well as utilization stage. This paper focuses on the utilization stage of an RMS and introduces a methodology to effectively adjust scalable production capacities and the system functionalities to market demands. It is supposed that arrival orders of product families follow the Poisson distribution. The orders are lost if they are not met immediately. Considering these assumptions, a mixed integer nonlinear programming model is developed to determine optimum sequence of production tasks, corresponding configurations, and batch sizes. A genetic algorithm-based procedure is used to solve the model. The model is also applied to make decision on how to improve the performance of an RMS. Since there is no practical RMS, a numerical example is used to validate the results of the proposed model and its solution procedure.     

制造协作组织形成过程任务性能参数逆向优化

深入分析了制造协作组织形成过程的市场特性。针对产品制造任务性能参数的优化问题,提出正向优化与逆向优化过程模型,分析双向优化结构的宏观与微观特征。通过探讨可以发现,制造任务优化与制造资源配置是市场协作制造过程中的两个相互影响、密不可分的整体。通过针对逆向优化过程的研究,进行制造任务性能参数逆向优化过程的形式化描述,进一步构建任务参数优化的数学模型,并且运用矢量范数理论对模型的最优解存在性质进行论证。最后,在分析遗传算法的宏观与微观策略的基础上,利用基于实数编码的遗传算法对优化模型进行求解,用实例验证了优化方法与算法的有效性。