A predictive reactive scheduling method for color-coating production in steel industry

It is a difficult but challenging task for complex steel production to find effective schedules in a dynamic environment. In this paper, a predictive reactive scheduling method for the color-coating production in steel industry is investigated. In a practical production environment, the originally established schedules often need to be adjusted due to some unexpected events, which will break down the production continuity. Reactive scheduling is, therefore, essential for the production scheduling system to maintain the production continuity by reconciling the conflict between the originally established schedules and the current production status of the factory. To efficiently cope with such unexpected events, we propose a matching-up model whose objective is to minimize the impact on the originally established schedule and maintain its good quality. The experimental results on instances collected from practical production data show that the proposed method can provide robust and high quality schedules under a real-time production environment.     

冷轧薄板生产线组批调度模型与算法

针对冷轧薄板生产线流程长,产品种类多的特点,为提高合同的交货准确度,将一段时期内的生产合同进行组批处理,并对合同各批量的机组作业时间进行模糊预测,建立了具有模糊处理时间的冷轧生产线合同组批调度模型.模型将批量合同作为基本调度单元,将其归结为一类模糊Job Shop问题,并采用改进的单亲遗传算法与特殊的邻域搜索策略相结合的方法进行求解.通过上海宝钢冷轧薄板厂大量的生产数据进行仿真实验,批量平均交货期满意度达到90%以上,表明该调度模型与算法能够达到较好的应用效果.     

Oxide scale characterization of ferritic stainless steel and its deformation and friction in hot rolling

The oxidation kinetics of ferritic stainless steel 430 was studied in dry and humid air at 1090 °C by Thermo Gravimetric Analysis (TGA). Different atmospheres and heating times were adopted for reheating to obtain different compositions and thickness of the oxide scale. Hot rolling was performed on a 2-high Hille 100 experimental rolling mill at various reductions. Oxide scale thickness and composition were analysed with optical microscopy (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). The surface profiles were examined by a digital microscope, and the topographic features of the thin oxide scale surface were examined with an atomic force microscope (AFM) before and after rolling. The oxide scale surface and steel/oxide interface roughness were measured after rolling. Inverse calculation of the coefficient of friction was employed to analyse and the effect of oxide scale on friction in hot rolling. The coefficient of friction depends not only on the thickness of the oxide scale, but also on its composition and surface topography before hot rolling.     

混合型CIMS中生产作业计划系统的研究与实现

通过分析中国包装进出口天津公司纸箱厂混合生产过程的特点,生产作业计划的特点与存在问题,提出了适合该厂生产作业计划管理的解决方案,我们对引进的MRDII软件进行了二次开发,使其适应混合企业生产过程的特点,设计并开发了纸板排料子系统,并与MRPII系统有机集成,从而实现纸箱厂生产作业计划的编制,最后总结出CIMS环境下混合型企业生产作业计划的特点。     

Analysis of tribological feature of the oxide scale in hot strip rolling

In this paper, the effects of the flow stress of the scale and steel, and the friction coefficients at the scale-steel and the roll-scale interfaces on the final surface roughness have been studied. The surface roughness increases for both oxide scale and steel with an increasing friction coefficient at the roll-scale interface. However, the roughness increment is limited. The calculated roughness is close to the measured value. The temperature affects the scale roughness transfer, and the maximum difference is about 25% when the temperature is 850-1025 °C for rolling speeds 0.12-0.72 m/s. The developed model is applicable in hot strip mills.     

流程工业生产计划与调度系统的组态平台技术

由于流程工业生产计划与调度软件系统开发过程复杂、可重用性差,提出了一种流程工业生产计划与调度系统开发的组态平台技术方法.该方法以图形化组态的方式对系统进行设计和开发,并可以链接各种定制的算法,达到快速生成系统软件的目的.以此方法为基础,研制出了用于开发流程工业生产计划与调度软件系统的组态平台软件.实际应用结果表明,该组态平台软件使用简单、通用性强,可以有效提高流程工业生产计划与调度系统的开发效率.     

钢铁企业先进生产计划和实时生产调度技术的研究

为了解决钢铁企业目前由于缺乏生产计划和调度系统而造成的宏观调控和实时监控等方面存在的问题，在对现有钢铁企业的信息化体系结构和生产管理模式等进行理论研究的基础上，提出了基于MRP II与JIT相结合的特钢行业生产管理模式；采用多层递阶计划和动态实时调度策略，构建面向企业上层管理ERP和下层执行MES系统的集成化解决方案。实现了企业生产计划和调度的整体优化，建立了适合特钢企业经营管理与生产制造一体化的信息系统。     

The representative topography of worn hot rolling mill cylinders

In this paper, a method is proposed to extract the most representative surface topography from n surfaces. A criterion is proposed that allows rejecting irrelevant topographical maps. Then, this methodology is applied on the hot rolling process, on replicas of industrial surfaces. These analyses have shown the major difference between ICDP and HSS roll behavior in terms of topography. Carbides oxidation observations correlates lab studies from bibliography. We confirm that this methodology is relevant to industrial investigations, especially on phenomena requiring non-destructive protocol.     

Study on the oxidation of stainless steels 304 and 304L in humid air and the friction during hot rolling

In rolling process, the contact friction is of crucial importance for accurate modeling, optimum design and control of industrial rolling processes. It is important to characterize the features of the oxide scale of stainless steel in hot strip rolling because the scale on the strip surface affects friction coefficient and thermal conductivity coefficient. To some extent, the rolling force and friction condition depend on the thickness and the microstructure of the oxide scale. Oxidation tests of stainless steels 304 and 304L were carried out in a high temperature electric resistance furnace. The humid air in which the water vapour content can be controlled was generated and remained to flow into the chamber of the furnace in 2.5 × 10⁻⁴ m³/s to study the effect of humidity on the oxidation of stainless steels. The microstructure and thickness of oxide scale layer of stainless steels were obtained and two or three oxide layers can be found. The humid air has a significant effect on the growth of oxide scale. Hot rolling tests were carried out on Hille 100 rolling mill. The friction condition at the roll–strip interface during hot rolling of stainless steel was determined and the transfer of surface roughness was discussed.     

流程工业生产计划与调度系统的对象建模方法

为解决流程工业生产计划与渊度系统丌发的各类问题,提出了一种对象分析建模方法。该方法通过建江线长度属性进行数据抽象和封装,设计出具有通用性的流程工业生产计划与调度系统的对象类,并应用于流程工业中冷轧薄板生产过程。实践表明,建立的对象类与现实生产能高度吻合,大大提高了系统开发效率。     

基于Agent的生产调度混合协商策略研究

当前大多协商策略无法兼顾规划和反应能力,为此,本文提出一种短期规划与动态响应能力相结合的混合协商策略。该策略针对柔性车间生产调度问题和面对扰动的再调度问题,将组合拍卖与改进合同网相结合,通过规定相关智能体的动作和交互顺序,实现系统在平稳或扰动状态下的生产调度。基于上述协商策略,开发了一个基于智能体的生产调度原型系统,并通过仿真实验验证协商策略的可行性和有效性。     

考虑机器检修的圆钢热轧批量调度算法

针对圆钢的热轧批量调度问题,考虑实际生产中的机器检修计划对批量连续性加工的影响,以最大化产能利用率、最小化机器调整时间和订单提前拖期为优化目标,建立了多目标的整数规划模型,并提出改进的带精英策略的快速非支配排序算法对模型进行求解。算法结合问题的约束特征,采用改进的NEH算法生成初始解,并采用罚函数的思想设计适应度函数,对种群中存在的不合理解设计修复规则进行修复;针对遗传进化过程,设计了遗传操作方式,并在算法迭代过程中嵌入基于有限搜索范围的邻域搜索算法,避免算法陷入局部最优。实验结果表明,模型和算法对问题的描述和求解是可行有效的。     

线材热轧过程的三维热力耦合有限元模拟

运用有限元软件MSC.MARC及其接触分析技术,准确模拟了高速线材中轧区五道次热连轧过程.采用真实尺寸,计算并分析了轧制过程中的金属流动、轧制力、轧制力矩、应力、应变以及温度场等的变化规律,模拟结果为工艺参数的优化提供了依据,也对实际生产有重要的参考价值.     

订单型企业多目标生产计划的制定及其调度

针对制定订单式小批量生产计划问题,提出了一种使用动态随机投入产出函数来制定多目标生产计划的方法。针对生产调度问题,提出了联合使用最长加工时间优先(LPT)与遗传算法(GA)的混合遗传算法(HGA)来求解混合流水线的调度,并给出了一种新的编码方法,选择了相应的交叉和变异方法。研究结果表明,该计划制造方法能较好地满足订单型企业的随机性要求,而且生产计划编制效率高。该编码方法在保证染色体合法性的同时也保证了算法本身的随机性。某轧辊厂的实际案例分析结果也验证了所提出的订单型企业多目标生产计划的制定及其调度方法的可行性。     

基于免疫算法的生产调度现状与展望

为提高生产调度的效能,首先阐述了生产调度和免疫算法的概况,然后分类讨论了免疫算法在生产调度问题中的研究现状,最后分析了目前此类研究中存在的问题和不足,并探讨了基于免疫算法的生产调度问题进一步的研究方向.     

一种改进的半导体生产线批处理机调度策略研究

研究了半导体生产线上有加工类型限制的并行批处理机组调度问题,其目标是最小化总加权拖期交货损失,从而最大程度地满足客户的按期交货要求.在研究了ATC-BATC和DBDH规则的基础上,提出了一种改进的ATC-BATC调度规则,通过反馈控制局部在制品数量来改善系统性能,并通过仿真证明该规则能更有效地减小总加权拖期交货损失.     

1450mm热轧生产线上阶梯垫的新型算法

在以往热轧机上阶梯垫的选择过程时,只考虑了上工作辊的磨损,而没有结合上支承辊加入以及上支承辊的磨损问题,出现了无法装辊,或者装辊后由于HGC缸伸的过长,出现设备损坏等现象。介绍了上阶梯垫的新型算法,解决了以上问题。经过国丰钢铁厂试用,取得了成功的经验。     

A combined upper bound and finite element model for prediction of velocity and temperature fields during hot rolling process

In this work, velocity field and temperature distribution during hot strip rolling are predicted, employing a combined upper bound and finite element analysis. At first, a velocity field is proposed utilizing the principle of volume constancy, and then the velocity field is modified by means of upper bound theorem. At the same time, a thermal-finite element analysis is utilized to determine temperature distribution within the metal as well as to calculate the flow stress of deforming material. The model is capable of considering the effects of different factors on temperature and velocity distributions such as rolling speed and interface heat transfer coefficient. In order to verify the predictions, the calculated time-temperature curves as well as roll forces have been compared with the measured ones and a good agreement has been observed. The main advantage of the present model is that the model requires relatively lower computational effort in comparison with the required one in standard finite element codes.     

一类多层生产排序问题的建模与求解

针对一类航天企业普遍存在的多层生产排序问题,建立了整体优化模型,并根据多层生产排序的特点,提出了一种分解-协调的建模思想及其求解策略.在建立三层子问题独立优化模型的基础上,依据各层工件可开工时间及设备最早可用时间对优化解进行自下而上的协调,逐步获得各层子问题的最优解,进而获得整体问题的满意解.采用该方法对来源于实际企业的多层排序问题进行建模和求解,所得结果较实际结果有显著提高,验证了其有效性和实用性.     

求解分布式混合流水线调度问题的改进双层嵌套式遗传算法

针对分布式混合流水线生产的生产调度问题,模拟实际排产中的排产到线和排产到时的排产策略,提出了基于改进双层嵌套式遗传算法的两层优化模型。外层依据流水线分配平衡和准时交货等基本原则总体上解决生产订单在流水线之间的分配问题,内层以最小生产时间为主要目的求解流水线的生产订单生产次序问题。考虑到双层嵌套式遗传算法的时间复杂性,基于模糊逻辑理论设计了一种模糊控制器来动态调整遗传算子,并采用主动检测停止方法,提高算法效率。使用某空调工厂的实际生产数据验证了算法的可行性、计算结果的准确性及排产策略的有效性,为高级计划与排程(Advanced Planning and Scheduling,APS)中大规模复杂供应链调度问题提供了可借鉴的方法。