双资源约束的鲁棒Job Shop调度问题研究

针对机器-工人双资源约束下加工时间具有随机性的Job shop调度问题(Job shop scheduling problems,JSSP),考虑工人熟练程度差异和工人数量不足的约束,采用鲁棒调度的方法建立机器-工人双资源约束的鲁棒Job shop调度模型(Dual-resource constrained robust JSSP,DR-RJSSP).鉴于DR-RJSSP同时考虑工人合理指派和双目标优化,提出机器-工人两阶段指派方法,在主动降低加工时间随机扰动的同时最小化工人约束对调度性能的影响.其次,提出多目标混合分布估计算法求解DR-RJSSP,以得到兼顾调度性能和鲁棒性的Pareto解集.最后,采用8组仿真算例将所提出的兼顾工人熟练程度和负载均衡的指派策略与基于熟练程度的指派策略和随机指派策略进行对比,验证了所提指派策略的Pareto优化性能.此外,通过对制造企业调度案例的仿真分析,验证了基于两阶段指派策略的MO-HEDA求解DR-RJSSP的有效性.     

双资源约束下预防性维护与作业车间集成调度模型

在生产过程中需要对机器进行预防性维护和故障维修,但维修工人数量少、培养周期长、人力成本高,致使维护计划时必须考虑人力资源约束。针对该问题,建立了考虑维修工人资源和机器资源双约束的维护和生产活动集成调度模型;根据威布尔公式计算出最佳预维护周期,设定预维护时间窗口,在时间窗口内进行预维护,根据机器累计加工时长进行判断,脱离窗口可能需要的故障维修;最短生产周期为优化目标,采用改进遗传算法求解模型,采用三层编码方式,引入精英保留策略,通过算例仿真实验寻找作业车间维修工人最佳配比数量。与未考虑双资源约束的研究进行对比,验证模型与算法的可行性与有效性。     

基于QUEST的用户自定义仿真功能实现

QUEST是一款进行制造系统离散事件仿真的软件。研究了QUEST软件的两种用户自定义模式,并结合实例说明了QUEST中根据用户需求建立运动模型和运行逻辑的方法。对QUEST软件的用户扩展功能的应用作了详细的介绍,通过实例展示了应用运动模块创建的机器模型运动仿真和一个用SCL(仿真控制语言)驱动的用户中断生产过程仿真,两种方法均具有通用性,仿真效果明显,体现了QUEST在用户自定义方面的优越性。     

制造车间生产过程网络鲁棒性分析

针对制造车间生产过程的鲁棒性问题,从复杂网络视角出发,借鉴耦合映像格子,建立了制造车间的网络故障模型;通过仿真分析的方法研究了制造车间网络的故障传播特性。仿真中采用随机故障和蓄意触发两种触发机制,分析了不同的外部扰动、不同的触发机制以及不同的耦合强度对网络故障传播行为的影响。以实际某变压器的生产过程为例进行仿真,结果表明外部扰动越大、耦合强度越大制造网络发生故障的概率越大、网络在随机触发下具有较好的鲁棒性,在蓄意触发下表现出脆弱性。     

随机产量下的二级供应链契约协调

研究了由单个供应商与生产商构成的两级供应链中,当生产商为领导者且面对确定性产品需求,供应商是追随者且面对随机产量时的契约协调问题.考虑了乘法型和加法型两种随机产量情形,在集中控制模式下,研究了供应链系统的最优生产问题;在分散控制模式下,建立了由批发价契约和批发价与原材料缺货惩罚、剩余原材料收购策略联合形成的四种契约下的Stackelberg博弈模型.通过参数分析发现博弈结果能够协调乘法型随机产量供应链,并给出了相应契约参数的解析解,而对加法型随机产量,博弈结果不能达到供应链协调.通过算例进行了验证,并对这四种契约的特点进行了分析比较.     

作业车间区间型多属性瓶颈识别方法

针对扰动情形下作业车间瓶颈识别时机器的特征属性难以用确定值表示的问题,采用区间形式描述机器特征属性,构建了区间型多属性瓶颈识别模型,提出了区间TOPSIS多属性瓶颈识别方法.考虑瓶颈识别与瓶颈利用的紧密关系,提出了先进行瓶颈利用再进行瓶颈识别的统一框架.其中瓶颈利用层基于Plant-Simulation 仿真平台设置了机器故障等随机扰动,采用遗传算法对扰动情形下的调度问题进行了优化仿真,获得了适应扰动情形的最优调度优化方案;瓶颈识别层基于调度优化方案,综合考虑了瓶颈的多维特征属性,采用区间TOPSIS多属性瓶颈识别方法识别了瓶颈机器.通过与机器利用率、瓶颈出现率和移动瓶颈识别法等进行比较,验证了所提方法的有效性.最后,分析了制造成本和原材料成本两个参数对瓶颈识别的影响.     

生产系统设备预防性维修控制策略的仿真优化

为了有效地降低设备故障的维修与设备维护成本,提出了用计算机仿真方法实现预防性维修的关键技术。运用残余役龄和残余因子的概念,推导了三种故障维护策略下故障时间的随机抽样公式,给出了仿真分析的一般步骤,建立了有限时间区间下设备预防性维修控制策略的数学模型,对该模型进行了仿真分析,并用数值解法的结果验证了仿真结果,结果表明,仿真具有较高的精度,是一种研究设备维护策略的有效方法。     

关于精确平均点度随机网络仿真模型的研究

为提高仿真模型的可信度,提出了一种随机网络生成算法。研究内容包括：随机节点的区域性分布,中心节点、OVERLAY功能节点的选择,实验推演新的概率连通公式,增加点度分类约束策略及随机网络快速连通策略等。在算法基础上建立了具有精确平均点度的随机网络仿真模型。对该随机网络仿真模型的性能做了一定的阐述、模拟和分析,表明该模型是通用性的、可定制的。与现有算法相比,该算法收敛性好,并能线性逼近所模拟的实际网络。     

基于单稳态随机共振的冲击信号自适应检测方法研究

针对强背景噪声环境下微弱故障冲击信号特征提取困难等问题,对单稳态随机共振系统和衡量指标等方面进行了研究,对低速回转支承的故障诊断策略进行了分析,提出了一种基于单稳态随机共振的冲击信号自适应检测方法。考虑到系统参数的关联性,利用灰狼优化算法(GWO)对系统的多个参数进行了优化,实现了系统参数间的同步优化过程;并以加权负熵指标作为GWO的适应度函数,对仿真冲击信号和低速回转支承振动信号进行了状态监测与故障分析。研究结果表明:该系统方法简单易行、收敛速度快、参数优化效果理想,能够在强背景噪声环境下,有效地利用噪声能量来增强微弱故障信号,凸显仿真冲击信号的特性;能准确地诊断出低速回转支承故障模式,在工程实际中具有良好的工程应用前景。     

基于案例的动态RCM维修管理模式及共应用分析

介绍了动态RCM、设备重要度分析和设备故障模式风险分析的原理,并结合30万t／年尿素设备动态RCM实施过程,详细介绍了设备重要度分析、设备故障模式风险分析和维修维护策略制定的过程。实践证明：动态RCM对于确定预防性维修需求、优化维修制度具有重要应用价值。     

基于Petri网的非串行制造系统的可靠性分析

对带有中间缓冲区的非串行系统深入研究其可靠性问题,建立基于广义随机Petri网的可靠性模型,着重考虑出现的装配、拆分以及按不同比例进行装配或拆分的加工工序,其中间缓冲区可用度对机器可用度的影响,在此模型基础上,采用缓冲区可用度定理,对中间缓冲区和机器本身的状态转移概率分别分类求解,计算出相应的缓冲区可用度和等效机器可用度;同时通过功能可靠度指标,对整个加工任务车间的可靠性进行总体评价,从时间量和产品量因子出发,来衡量由于生产率的不平衡以及中间缓冲区的库存太小,引起生产流程中传输道的阻塞和缺料,进而造成的相关工件的加工时间延迟等问题。以三台机床和两个待加工工件的加工装配单元为例,验证该模型与分析方法的有效性。     

Work flow control in the flexible flow line

This research involves the development and evaluation of a part flow control model for a type of flexible manufacturing system (FMS) called a dedicated flexible flow line (FFL). In the FFL, all part types flow along the same path between successive machine groups. The specific objective of the part flow control model for the FFL is to minimize makespan for a given set of parts produced in a FFL near-term schedule, given fixed available buffer constraints. The control model developed in this research involved the repeated, real-time execution of a mathematical programming algorithm. The algorithm attempts to release the right mix of parts at the tight time to keep the FFL operating smoothly. The focus of the approach is directed toward managing WIP buffers for each machine group queue. The algorithm specifically incorporates stochastic disturbance factors such as machine failures. Through a limited number of simulation experiments, performance of the control model is shown to be superior to other parts releasing and control methods reported in the literature.     

Manufacturing system modeling and performance evaluation based on improved stochastic statechart

Stochastic statecharts are widely used in modeling systems. Considering that the comparability between different subsystems can streamline the modeling process, a stochastic statechart is improved by using the abstract sub-system and general system chart to express the comparability and integrity of a stochastic statechart respectively. Per formance data can be obtained by using a continuous-time Markov chain, which is transformed from a manufacturing system model described by the improved stochastic statechart. The case study shows that the improved stochastic statechart can effectively simplify the modeling and performance evaluation process and the results are useful to the configuration and optimization of a manufacturing system. __________ Translated from Journal of Beijing University of Technology, 2006, 32(8): 693–698 [译自: 北京工业大学学报]     

Makespan minimization for m-machine permutation flowshop scheduling problem with learning considerations

Increased complexity of current manufacturing systems together with dynamic conditions and permanent demands for flexible and robust functionality makes their management and control very difficult and challenging. Workflow simulation is an effective approach to investigate dynamic workflow scheduling policies and evaluate the overall manufacturing system performance. The results attained in simulation model can give directions on how to maximize system output when selecting an appropriate scheduling practice for a real system. In this paper, we investigate the abilities of multi-agent systems in combination with dynamic dispatching rules and failure handling mechanisms to manage dynamic environment conditions (such as machine failures) for systems in the production automation domain. We measure system robustness by systematically assessing the total system performance (e.g., number of finished products) in a number of representative test cases. We use an agent-based simulation environment, MAST, which has been validated with real-world hardware to strengthen the external validity of the simulation results. We investigated the performance of a re-scheduling component which uses four different policies that define how to adjust the system schedule in case of machine disturbances/failures. In the context of the empirical study the Complete Rerouting re-scheduling policy outperformed all other policies.     

Influence of Residual Stresses Introduced by Manufacturing Processes on Bearing Endurance Time

By enhancing surface properties and by reducing weight and size of machine elements, future trends in resource efficiency for machines can be fulfilled. Rolling element bearings are widely used machine elements. By improving their boundary zone properties, there is a potential to extend maintenance-free operating periods, postpone replacements or increase the lifespan of the complete system. The aim is to set favorable boundary zone properties by enhancing the residual stress state within the manufacturing process. For this, the processes hard turning and deep rolling were investigated. The influence of the initial residual stress state on fatigue life was calculated using a model based on the approach of Ioannides and Harris. The resulting residual stresses after the manufacturing process and their changes during operation in a bearing test rig are discussed and compared to those of standard bearings. The tests prove that pre-induced residual stresses increase is able to significantly delay rolling contact fatigue-related bearing failures.     

Maintenance Integration in Manufacturing Systems: From the Modeling Tool to Evaluation

In manufacturing systems, wear-out and eventual failure are unavoidable. However, to reduce the rate of their occurrence and to prolong the life of equipment or the capacity for extended productive use of the equipment under the necessary technological functioning and servicing, maintenance can be performed. For large manufacturing systems, maintenance integration involves a particular development concerned with both complexity models and computing time. This paper presents an effective way of modeling complex manufacturing systems through hierarchical and modular analysis by using stochastic Petri nets and Markov chains. In the proposed approach, the integration of maintenance policies in a manufacturing system is facilitated by the development of a generic model. With this generic modeling, the user doesn't need to code the strategies but only to instantiate the generic model with the structure of the manufacturing system. This method allows various maintenance strategies to be coded in the generic model with the aim of studying their influence on system dependability and performance.     

全自动可转位刀片周边磨床的可靠性分析

在对全自动可转位刀片周边磨床早期故障以及失效机理分析的基础上,采用试验方法,对其整机及关键功能部件进行了可靠性研究,获得指数分布下机床的真实故障数据、故障分析结果和磨床的平均无故障运行时间,提出该磨床在今后设计、制造和装配过程中的建议.试验证明,该机床的可靠性指标符合要求,在改进后将获得更高的可靠性指标值.     

Analysis procedure of robot’s loading performance by using actual data

The usage of robots in manufacturing systems is increase. For material handling, the robot loads and unloads a workpiece on and from the given position of a machine, respectively. A robot without a closed control system may fail in such a performance. In order to analyze the stochastic property of the robot’s loading performance, playback accuracy on a given position is measured under given experimental conditions and them a statistical procedure on the measured data is described. run test is used to determine whether the loading failure of any one cycle is random or not. Proposed method using real data of 400 consecutive cycles can be applied to build an analytical model on a manufacturing system using robots as material handling equiplment.     

数控机床早期故障消除技术

针对国产数控机床可靠性差的问题,从故障率浴盆曲线建模分析入手,量化确定了机床的早期故障区,深入分析了早期故障产生的原因,结合可靠性试验技术,阐述了早期故障消除技术的机理,在此基础上建立了早期故障消除的技术体系, 阐述了早期故障消除过程,即故障收集、故障分析、可靠性试验、故障消除阶段的研究思路、内容和方法。最后将该技术运用到数控机床生产企业,案例表明,该技术可以有效提高数控机床的可靠性。      

云制造环境下基于离散Markov跳变系统的机床装备资源动态优选方法

针对云制造环境下加工任务执行过程中机床装备资源易受紧急插单、加工质量异常、设备运行故障等高频随机扰动影响,致使产品加工服务质量(QoS)不能满足客户个性化需求的问题,提出一种基于离散Markov跳变系统的机床装备资源动态优化选择方法.首先,结合云制造服务运行特点,构建了云制造环境下面向加工任务执行过程的服务质量动态演化...