VSSI EWMA均值控制图和预防维修联合经济设计模型

针对设备异常导致过程质量均值发生漂移的可修系统,提出一种考虑最小维修的样本容量和抽样区间均可变(VSSI)的指数加权移动平均(EWMA)均值控制图和预防维修集成决策方法。在假设控制图误报警实施最小维修、正确报警和预防维修实施完美维修的前提下,分析确定了系统存在的3种更新策略情景;在此基础上,以单位时间期望成本最小化为目标构建了VSSI EWMA均值控制图和预防维修联合经济设计模型,并给出了基于帝国竞争算法的模型求解过程。算例分析结果表明,该模型由于考虑了最小维修以及控制图与预防维修的耦合关系,能够通过对决策参数的进一步优化降低系统综合成本。最后,利用正交试验设计和回归分析方法,对模型参数的灵敏度进行了分析。     

VSS EWMA均值控制图和预防维修联合经济设计模型

针对生产过程质量特性均值漂移由设备异常导致的可修系统,提出一种可变样本容量指数加权移动平均均值控制图和预防维修联合经济设计模型。在该模型中,系统被界定存在控制图误报警、正确报警、预防维修点到达3种更新情景;针对样本可变情况,分析得到了控制图两类错误期望概率;为避免平均失控运行长度带来的计算复杂等问题,以抽样间隔为基本分析单元代替传统方法的失、受控两阶段分析模式,建立了各更新事件期望周期成本和时长的函数表达式,进而构建了单位时间期望成本最小化决策模型,并与蒙特卡罗仿真方法进行了对比分析。应用实例分析结果表明,该模型能够较真实地反映生产系统实际运行状况,并可为系统优化分析提供支持。最后,对模型参数进行了灵敏度分析。     

串行生产线预防维修可靠性研究

建立了串行生产线生产单元的可靠性模型,通过分析预防维修成本可知在各个预防性维修周期内存在一个最优值Ti使得总维修成本最低。为保证可靠性,建立了基于预防性维修策略的生产单元优化模型,基于可靠度约束,对优化模型进行改进。为保证生产的连续性,研究了生产单元缓冲区的库存控制,给出了最小理论库存量的计算公式和缓冲库存控制策略。研究了设备的等效可用度,可知可用度的提高量与役龄回退因子α和每次预防性维修时间θ有关,增大α或减小θ都可以提高设备的可用度。     

机会维修策略下的民机系统维修决策优化模型

以系统单位时间费用率和可用度为目标,构建了民机多部件系统不完全预防性维修多目标优化模型.引入机会维修思想,以部件机会维修可靠度阈值作为模型优化变量,将各部件维修方式按照时间相关性和结构相关性进行优化组合.模型采用改进后的自适应变异粒子群算法(Adaptive mutation particle swarm optimization,AM-PSO)求解Pareto最优解集.利用民机某型发动机反推控制和指示系统实际维修数据进行模型验证与分析,结果表明:在有限运行周期内运用本文的多目标优化模型与方法进行预防性维修活动,能有效降低系统维修成本的同时提高其可用度.     

VSSCL均值控制图和预防维修策略联合经济设计

针对输出质量特性服从正态分布的随机偏移单部件可修系统,研究了可变样本容量和控制线(Variable Sampling Size and Control Limits,VSSCL)均值控制图和预防维修策略联合经济设计问题。首先,构建了VSSCL均值控制图和预防维修策略联合经济设计的集成框架,揭示控制图和预防维修策略运行的耦合机制;然后,基于VSSCL均值控制图和系统状态特征参数,针对给出的集成框架确定了可能形成系统更新的四个维修事件的发生概率,并进一步利用更新过程理论和全概率公式,建立了VSSCL均值控制图和预防维修策略联合经济设计的平均单位时间成本最小决策模型;同时,针对具体实例,将构建的联合设计决策模型和独立设计决策模型进行比较分析,结果表明联合设计决策模型具有明显的经济优势;最后,利用回归正交试验设计方法对模型参数的灵敏度进行了分析。     

考虑延迟监测的预防维修和EWMA方差控制图联合决策模型

针对设备异常将导致过程质量方差发生漂移的可修系统,提出了一种考虑延迟监测的预防维修和EWMA方差控制图联合决策模型。首先分析确定了预防维修和过程质量监控联合决策生产系统在延迟监测条件下形成的6种更新策略;然后基于每个抽样间隔期的分析思路,建立了每种更新策略的期望周期和成本,并根据更新过程理论构建了联合优化延迟监测期、预防维修规划周期及EWMA方差控制图参数(样本量、抽样间隔、控制线系数及平滑系数)以实现单位时间期望总成本最小的经济决策模型。实例分析表明,模型由于充分考虑了延迟监测问题,能够获得比不考虑延迟监测模型更优经济效益的决策结果。     

多部件重要度系统机会维修策略的优化

为解决复杂系统维修成本昂贵的问题,这里引入机会维修系数和部件的Birnbaum重要度,首先计算出系统中各个部件的预防维修间隔期,以系统在一定运行周期内的成本最小化为目标,以机会维修系数与部件Birnbaum重要度的比值和系统的可用度满足一定要求为约束条件,建立以部件重要度为基础的串联系统机会维修优化模型.对所构建的模型...     

基于改善因子的系统部件维修间隔优化方法

针对民用飞机系统部件维修间隔优化问题进行研究。为了描述维修活动对系统的影响,引入改善因子描述维修活动对工龄的恢复效应,在不完全维修模型的基础上,构建了以单位时间总维修成本最小为目标函数的周期性不完全预防维修优化模型,得到了不完全维修条件下最佳预防维修时间间隔和最佳维修次数。最后,采用航空公司的实例进行验证,表明模型是可行的。     

基于随机Petri网的复杂机械设备可用度分析方法研究

设备的可用度是衡量设备运行过程中随机故障的主要指标,提高其可用度是设备优化运行过程中极为重要的一环。通过分析不同维修策略下设备状态的演变规律,研究不同状态之间的时间依赖关系,建立基于随机Petri网的复杂设备可用度模型。模型着重描述设备运行过程中的劣化状态以及不同维修策略对运行过程的影响。在此模型的基础上,根据设备不同维修策略分析模型的可达图,构造同构的马尔可夫链模型,求解模型不同状态下的各个稳态概率,计算不同维修策略下的设备可用度。通过可用度的求解可得到较优的设备维修策略,从设备预防性维修效率和故障维修效率因子出发,定量分析这两个因子对设备可用度以及设备维修费用的影响,并给出趋势图。以一个实例说明该模型及分析方法的有效性。     

基于仿真的多部件设备机会维修多目标决策优化方法

提出一种基于仿真的多部件设备机会维修多目标决策优化方法，考虑了多种维修方式、多种机会维修策略、非预期故障的随机持续时长和成本以及随机的预防性维修时长，利用蒙特卡洛仿真计算系统可用度和总成本，多目标粒子群算法进行求解最佳维修方式。将该方法应用到电子组装线的某生产设备，结果显示，同时考虑了随机故障和预防性维修的机会维修策略具有更优的Pareto前沿，能够进一步优化系统可用度与系统总成本，并对可用度和总成本的随机分布进行了分析。     

Joint optimization of lot-sizing and maintenance policy for a partially observable two-unit system

In this paper, we present a new model to find the jointly optimal economic manufacturing quantity (EMQ) and preventive maintenance (PM) policy for a complex production facility. Unlike the previous joint models which dealt with EMQ and maintenance policy considering a single unit production facility and traditional maintenance approaches, we consider a production facility which consists of two modules with economic dependence. The more expensive module (unit 1) is subject to condition monitoring (CM), and only the age information of the second module (unit 2) is available, which follows a general distribution. The deterioration process of unit 1 is modeled as a continuous time hidden-Markov process. CM data is available at the end of each production run, and it provides only partial information about the hidden state of unit 1. The failure state of unit 1 is observable at any time. The objective is to develop a jointly optimal lot sizing and maintenance policy for a two-unit production facility using multivariate Bayesian control approach by minimizing the long-run expected average cost per unit time. The problem is formulated and solved in the semi-Markov decision process (SMDP) framework. Also, a formula for the mean residual life (MRL) of the production facility is derived, which is an important statistic for practical applications. A practical example of the wind turbine CM and maintenance is provided and a comparison with other policies shows an outstanding performance of the new model and the control policy proposed in this paper.     

基于状态的单部件维修策略优化方法

为降低装备中关键单部件的预防性维修费用,把部件劣化过程看成离散状态变换的过程,提出了部件从投入使用开始到发生一次故障进行修复的平均时间间隔、平均检查次数、平均预防性维修次数和平均维修总费用的计算表达式.以单位时间内平均总维修费用最小化为目标,建立了基于状态的预防性维修策略优化模型及其求解方法.实验结果表明,本方法可以快速确定部件的检查时间间隔和预防性维修状态,有效地降低单位时间内平均总维修费用.     

基于威布尔模型的舰炮武器预防性维修系统构建与优化

针对复杂的舰炮武器构建一种新的预防性维修系统,按照维修计划、硬件失效、子系统FMECA、重要功能决断、维修任务评估和确定维修间隔期六个步骤详细分析了系统工作过程;给出了预防性维修能实际应用的条件,并通过基于威布尔分布的失效数据分析来确定系统的预防性维修间隔期.最后给出的算例中,对于收集的失效数据,在确定的恢复性维修费用与预防性维修费用比例下,利用威布尔模型优化预防性维修间隔期,结果表明预防性维修相对于恢复性维修具有良好的经济效果.     

基于半马尔可夫过程的冷备系统维护策略优化

为了提高系统的可靠性,构建了两机冷备系统,提出了基于半马尔可夫过程的冷备系统预防性维护模型,该模型考虑随机失效、退化失效两种失效形式,采用了小修、大修、预防性维护相结合的维护方式。基于半马尔可夫理论及再生点技术分析了系统运行中的状态变化过程,建立了马尔可夫更新方程组。通过拉普拉斯变换求得系统首次平均失效时间和稳态可用度的函数表达式,并分别以系统首次平均失效时间和稳态可用度为可靠性指标求解最佳预防性维护策略。最后通过实例分析了不同参数变化对系统可靠性及最佳预防性维护周期的影响。实验结果表明,所提出的建模方法对解决冷备系统维护决策具有指导意义。     

以可靠性为中心的维修成本优化模型及其应用

分析各种维修方法的特点,剖析以可靠性为中心的维修(RCM)与其它维修方法之间的内在联系,给出设备维修评价指标体系。以广义维修成本最低为目标,以设备可用度为约束条件,以维修周期为优化变量,提出了以可靠性为中心的设备维修成本优化模型。采用蒙特卡洛仿真和遗传算法进行模型求解,实现维修周期和维修成本的优化,以一液压-机械复合传动系统为例,验证方法的有效性。     

Metaheuristic-based inspection policy for a one-shot system with two types of units

In this paper, we address an inspection policy problem for a one-shot system with two types of units, namely, Type 1 units that fail at random times and Type 2 units that degrade with time. Interval availability and life cycle cost are used as optimization criteria and estimated by simulation. We determine inspection intervals, preventive replacement ages of Type 1 units, and preventive maintenance thresholds of Type 2 units that have minimal life cycle cost and satisfy the target interval availability during inspection periods. A simulation-based optimization procedure using a hybrid genetic algorithm is proposed to find near-optimal solutions. Numerical examples are studied to investigate the effects of model parameters on optimal solutions and compare the hybrid genetic algorithm with the general genetic algorithm.     

考虑可靠度和可用度的民机维修间隔优化研究

针对民机维修间隔优化的问题,运用可靠性分析和可用性分析的方法确定最优维修间隔。对于符合三参数威布尔分布的民机部件,提出采用改进的极大似然估计法求解分布参数估计值;并以可靠度阈值为约束条件,可用度最大为目标,建立了预防性维修间隔优化模型。利用遗传算法进行求解,制定出最优维修间隔。通过实例分析,讨论了部件在不同维修水平下的最优维修间隔,结果表明该优化模型能够较好地制定出符合要求的最优维修间隔,为民航企业合理制定维修计划提供了理论依据。     

Reliability-based maintenance optimization under imperfect predictive maintenance

The reliability-based maintenance optimization model has been focused by the engineers and scholars but it has never been solved effectively to formulate the effect of a maintenance action on the optimization model.In existing works,the system reliability was assumed to be increased to 1 after a predictive maintenance.However,it is very difficult in the most practical systems.Therefore,a new reliability-based maintenance optimization model under imperfect predictive maintenance (PM) is proposed in this paper.In the model,the system reliability is only restored to Ri (0相似文献   

Optimisation of opportunistic maintenance of a multi-component system considering the effect of failures on quality and production schedule: A case study

For a manufacturing equipment, any unplanned breakdown during the production period results into a high production loss. To keep the manufacturing facilities in good condition, preventive maintenance is planned. However, because of limited time and availability of resources, not all the system components can be or need to be repaired/replaced during a planned opportunity. Hence, the unplanned breakdowns can also be considered as an opportunity to do the maintenance activities for other components to take the advantage of economic dependency in multi-component system. However, when the system is under maintenance, it is very conservative to take the decision of maintenance actions on the components because of limited available time and resources. For such situation, this paper consider an opportunistic maintenance model for a multi-component system to take maintenance decision with a constraint on available time and the system availability requirements. The maintenance decisions for each component involves one of the three actions namely, repair, replace or do nothing to achieve the target availability with minimum maintenance cost. The model also considers the effect of component failures on the quality of product being manufactured as well as the production schedule on the machine. The cost of rejections is considered in the total failure cost along with the maintenance and downtime costs. The production schedule delay factor is considered as a constraint for the maintenance decision to account for the effect on production schedule delay. The optimal solution for the model is obtained using three solution methodologies namely simulated annealing, genetic algorithm and sequence heuristics. Using a real-life example of high pressure die casting machine, the opportunistic maintenance approach is demonstrated and results are discussed.