改进GA算法求解自动开票流水线生产调度问题

依据某应用企业的发展需求,对该企业的自动开票流水线进行了研究,将该流水线归类为一种特殊缓冲区约束的三阶段装配流水线问题.在传统装配流水线调度问题的基础上进行了改进,依此对自动开票流水线所代表的一类调度问题进行了数学模型的描述,同时根据自动开票流水线的生产特点,对遗传算法的编码解码、种群初始化以及局部搜索方面进行了优化,...     

PLC与CIMPLICITY在汽车流水线控制系统中的应用

研究了以美国罗克韦尔公司的Logix5561系列的PLC作为设备层的控制核心,上位机CIMPLICITY为监控系统的车间滚床控制系统。其硬件主要有Logix5561PLC、三菱A700变频器等组成,完成汽车流水线系统的控制任务和现场的数据采集,并由CIMPLICITY软件完成系统的监控。在现场的实际运行中表明,该系统合理控制承载橇体的滚床的运行速度,获得较好的控制精度,使汽车装配流水线流畅快捷,减少了工人的劳动强度,达到了节能降耗的目的。     

FinePix 9500的产房

仙台工厂是世界上规模最大的数码相机工厂之一,由于数码相机市场需求和机型变化非常大,因此这个工厂采用了“岛式”(cell)生产格局。与传统的流水线上每个工位只负责一个简单的装配不同,岛式生产中每个工位要完成多个装配动作,实现一个完整部件的安装。因此,传统流水线需要多个工位完成的操作在岛式格局中仅仅几个工人就可以实现。以最新的S9500为例,一条典型的最终装配线上仅有9个工位,还包括多个检测控制工位。这种“短粗”的生产线比较节省空间,我们看到,在一个车     

基于控制网的装配流水线监控实现

基于罗克韦尔的ControlNet控制网,使用罗克韦尔软件,实现装配流水线的逻辑控制和上位监视。在罗克韦尔运动控制台上,通过连接在控制网中的两台ControlLogix控制器,使用RSLINX和RSNETWORKS FOR CONTROL NET软件,进行控制网组态配置;使用RSLOGIX5000软件,进行装配流水线的逻辑控制编程;使用RSVIEW SE软件,进行上位人机界面组态。实验证明,在控制网上实现工业生产过程的控制及监视具有广阔前景。     

考虑批量分割的单元装配系统工作量平衡联合决策模型

针对日本式单元化生产中批量大小不合理导致单元间工作量不平衡的问题,在单元装配系统构建过程中考虑批量分割,构建流水线向单元装配系统转化的多目标优化模型.该模型以最小化总完工时间和最小化工人总工时为目标,对转化过程中单元构建和批量分割进行联合决策.考虑到多目标优化问题特点以及解空间复杂度,增加局部搜索策略,对算法进行改进,提出INSGA-II算法,设计了基于游标的编码方式表示批量分割,满足单元数量动态变化下批量划分约束.在进化过程中不断优化各单元对应产品种类以及批量大小,平衡单元间工作量,缩短总完工时间.最后,通过数值算例验证所提出方法的有效性,结果表明在产品数量波动较大的情况下,考虑批量分割能更好地平衡单元间工作量.     

吉祥星:金刚钻在握

走进位于深圳某工业区的吉祥星厂区,井然有序的厂区环境,颇有国际企业化企业的风范。纤尘不染的厂房内,工人一丝不苟。物料间、SMT贴片车间、装配间、成品间等一应俱全。罗德与施瓦茨测试仪、雅玛哈高精密贴片机、ROSE检测仪、BGA返修台、恒温恒湿测测试箱、SMT贴片机、锡膏厚度检测仪等一台台、一部部高新技术设备,为流水线上成千上万的产品严把质量关。     

保持外观的CAD模型轻量化技术

随着CAD/CAM技术的发展,整个产品的设计、虚拟制造和数字化样机都可在计算机中完成,使得包含大量数据的复杂装配体(即大装配体)的设计成为产品设计过程中的必需元素。由于大装配体模型数据量庞大,在普通PC机中处理极为不便,为了提高处理速度,需要对大装配体模型进行简化。在不改变装配模型格式和整体外观的前提下,提出了两种装配体模型的轻量化方案：1)从装配体中删除隐藏的零部件;2)从装配体中删除隐藏的特征。零件和特征的可见性是通过从多个视点预渲染装配模型,然后读取渲染缓冲区的结果并进行分析而得到。实验结果证实该算法能在不改变CAD模型格式和外观的前提下准确地删除装配体中的隐藏零件和特征。     

基于MT6056I触摸屏和PLC的装配流水线控制系统

针对饮料加工车间流水线上四组传送带组成的一个椭圆工作台上所需完成的加饮料、盖盖子、打标签等三个动作,给出了采用西门子公司的S7-300型PLC作为控制器,并采用维纶MT6056I触摸屏作为操作界面来设计饮料瓶自动化装配流水线的控制系统设计方法。系统可大大解放劳动力,提高企业生产效率。     

基于B/S结构的协同装配的关键技术

分析了协同设计中协同装配的应用模式。在具备协同感知的前提下针对同步协同装配和异步协同装配两种应用模式分别提出对应的体系结构设计。提出基于B／S结构协同装配的具体实现方法，并实现了一套基于B／S结构的协同装配工具。     

基于SPSO的机械流水线负载任务分配方法

在弱通信条件下,传统的机械流水线任务分配方法采用任务的随机分配,无法根据流水线的实际负载能力,将应有的任务量分配到相应的流水线上。提出一种基于简化粒子群优化算法(Simplified particle swarm optimization algorithm,SPSO)的高效机械流水线任务分配方法,首先对每个流水线的实际负载能力进行动态评估。然后采用粒子群优化算法对所有流水线负载分配相应的计算任务。由于每个负载的任务量是根据实际的流水线性能来分配的,所以可以使得全局的效率最优化。最后通过实验对算法的性能进行验证。结果显示,改进方法在基于粒子群优化的机械流水线任务分配下,任务根据流水线性能,呈现很好的聚类,算法收敛性好,分配任务速度快,具有很好的应用价值。     

应用遗传算法求解第一类装配线平衡问题

装配线的负荷平衡对生产企业非常重要。负荷平衡的装配线可以使各工作站空闲时间减少,并使工作站之间负荷均匀,以保证装配线时间损失率最低。针对第一类装配线平衡问题,首先对该问题进行了分析,在此基础上,建立了问题的数学模型。进而给出求解该问题的遗传算法,设计了该遗传算法的编码模式和译码方法,构造了适应函数,确定了初始种群的选取方法和种群的选择机制,并给出了种群的交叉和变异方法。通过求解某实例的装配线平衡问题,显示了这种算法的有效性。     

多目标遗传算法在混流装配线排序中的应用

混流装配线实现在一条流水线上装配多种不同类型的产品。该文在总结混流装配线排序问题的基础上建立了二种排序的目标函数：最小化工作站的闲置与超载时间和保持均匀的零部件消耗速率。引入了基于Pareto理论和小生镜单元技术的适应度函数及选择算子构建了多目标遗传算法用于混流装配线的排序优化问题。通过一个混流装配线的多目标排序实验,验证了该方法的有效性。     

Automatic generation of a fuzzy rule base for constant turning force

An automatic fuzzy rule base generation method is proposed to control nonlinear and timevarying turning processes with constant cutting forces. Based on this study, the optimum fuzzy rule base for the control of turning processes can be self-organized without the need for experienced manufacturing engineers. A fuzzy logic controller based on these fuzzy rules can adjust feed rate on line to achieve an optimal production rate in turning operations.     

Procedures for estimating desirable initial states of a production line: a comparative study

Two procedures for estimating initial states of a production line that ensure the line has a high probability of meeting the specified production target during a scheduled production shift are presented. The problem of determining desirable initial states is important in low variety, high volume production systems such as those from the automobile industry. One procedure is derived from design of experiments (DOE) theory whereas the other uses a genetic algorithm (GA). In the study it was determined that both procedures are straightforward to implement and produce good solutions to the problem. The results from the procedures are compared and their benefits and disadvantages are discussed.     

Job grouping in surface mounted component printing

The arrangement of operations in a production line for mounting the surface components on a printed circuit board is discussed. The production program includes a wide range of different products, which causes frequent set-up operations. The overall efficiency of the production line depends heavily on how the printing operations are organized. Set-ups cause delays which can be cut down by selecting carefully the feeders for the components and by solving a suitable sequence for the products. We describe an integrated production management system for job grouping. The system utilizes approximate algorithms for minimizing the number of component switching instants. A discussion of the exact minimization by using mathematical 0/1 integer programming approach is also given. The revision of the production management system has had a major impact on the productivity, and an increase of ca. 58% in the number of component insertions per hour is observed.     

Scheduling algorithm based on evolutionary computing in identical parallel machine production line

Evolutionary programming is a kind of evolutionary computing method based on stochastic search suitable for solving system optimization. In this paper, evolutionary programming method is applied to the identical parallel machine production line scheduling problem of minimizing the number of tardy jobs, which is a very important optimization problem in the field of research on CIMS and industrial engineering, and researches on problem formulation, expression of feasible solution, methods for the generation of the initial population, the mutation and improvement on the local search ability of evolutionary programming. Computational results of different scales of problems show that the evolutionary programming algorithm proposed in this paper is efficient, and that it is fit for solving large-scale identical parallel machine production line scheduling problems, and that the quality of its solution has advantage over so far the best heuristic procedure.     

Event-based receding horizon control for two-stage multi-product production plants

In this paper a receding horizon control approach for multi-product production plants is presented. Specifically two-stage plants are considered. In the first stage, a set of parallel production lines generates intermediate products from raw materials. In the second stage, the intermediate products are assembled into final products. A set of buffers for the intermediate products connects the production lines and the assembly line thus allowing a continuous production flow.

The focus is on plants where the switch between product types is less frequent than in the assembly line. The latter is mostly dictated by the external demand, while the first one is the main scheduling variable. A systematic event-based control approach using receding horizon control (RHC) techniques is proposed; specifically the production line flow is controlled in order to satisfy the time-varying request from the assembly line while minimizing the intermediate products storage and processing time. Experimental results underline the benefits resulting from the application of the proposed approach to a car engine manufacturing process.     

A genetic algorithm based approach to the mixed-model assembly line balancing problem of type II

Mixed-model assembly lines allow for the simultaneous assembly of a set of similar models of a product, which may be launched in the assembly line in any order and mix. As current markets are characterized by a growing trend for higher product variability, mixed-model assembly lines are preferred over the traditional single-model assembly lines.

This paper presents a mathematical programming model and an iterative genetic algorithm-based procedure for the mixed-model assembly line balancing problem (MALBP) with parallel workstations, in which the goal is to maximise the production rate of the line for a pre-determined number of operators.

The addressed problem accounts for some relevant issues that reflect the operating conditions of real-world assembly lines, like zoning constraints and workload balancing and also allows the decision maker to control the generation of parallel workstations.     

A multi-objective genetic algorithm for mixed-model assembly line rebalancing

When demand structure or production technology changes, a mixed-model assembly line (MAL) may have to be reconfigured to improve its efficiency in the new production environment. In this paper, we address the rebalancing problem for a MAL with seasonal demands. The rebalancing problem concerns how to reassign assembly tasks and operators to candidate stations under the constraint of a given cycle time. The objectives are to minimize the number of stations, workload variation at each station for different models, and rebalancing cost. A multi-objective genetic algorithm (moGA) is proposed to solve this problem. The genetic algorithm (GA) uses a partial representation technique, where only a part of the decision information about a candidate solution is expressed in the chromosome and the rest is computed optimally. A non-dominated ranking method is used to evaluate the fitness of each chromosome. A local search procedure is developed to enhance the search ability of moGA. The performance of moGA is tested on 23 reprehensive problems and the obtained results are compared with those by other authors.     

热轧带钢卷取温度联合控制算法设计与仿真

在热轧带钢生产线上,卷取温度的精确控制对带钢质量是至关重要的。详细研究了一个实际的热轧带钢卷取温度控制系统。建立了一种简化的动态控制模型,并用一个改进的遗传算法在线调整模型的参数。基于该模型提出了一个包括冷却反馈控制、前馈及自适应联合控制算法的控制器。通过建立一个更精确的仿真系统,达到指导现场生产的目的。实践结果证明提出的控制方法是有效的,仿真系统也具有较大的实际意义。