石化设备以可靠性为中心的智能维修系统

论述了设备诊断工程发展趋势和维修工程目标的优化,重点讨论以可靠性为中心的智能维修系统和消除信息化瓶颈的便携式数字智能巡检仪的开发与应用,为流程制造业提供安全、节约、绿色制造的科学方法和技术手段。     

基于CCR的串行生产系统机会维护建模方法

为提高串行生产系统的可靠性,在保证系统产能的同时降低系统维护成本,提出一种基于产能约束资源的设备预防性机会维护建模方法.在分析设备可用性和维护成本的基础上,对系统不同种类设备进行了预防性维护建模.在考虑瓶颈设备前非瓶颈设备是否进行机会维护的情形下,建立机会维护结余函数,并找出最佳机会维护策略.运用算例给出系统机会维护决策流程,并通过敏感性分析确定机会维护策略与相关参数之间的关系,分析结果表明所提出的建模方法是可行且有效的.     

混装生产排产序列MILP建模与仿真优化研究

混装生产时产品的投产顺序直接影响生产过程的连续、均衡和准时。建立混装生产MILP数学模型,得出满足客户需求的最小完工时间排产方案集;建立Flexsim生产车间仿真模型,统计得到在制造周期、在制品数量和设备效率的值;根据最小制造周期、最少在制品数量、最高设备效率的评价指标,构建了混装排产序列方案评价功效函数,筛选出综合性能最优排产方案。以某汽车发动机制造车间油漆混装生产线为例进行排产分析,研究所得到的油漆生产线排产方案D-D-D-D-H-H-H符合企业的生产实际,提高了其生产产能。     

基于“作业—资源流图”的装配系统分析模型快速构建方法

为支持复杂产品装配作业过程的优化与控制、降低建模复杂度,提出一种基于"作业—资源流图"的装配系统分析模型快速构建方法。该方法以装配站为基本分析单元,首先依据装配作业工序与资源的相互作用,建立面向装配现场的工序作业流和资源供给流,实现作业逻辑的快速、直观表述;采用离散事件和状态的提取与表示方法,将作业逻辑模型自动转化为具有离散事件分析能力的Petri网性能分析模型,并利用作业规则设定函数实现在制品和资源配置方案的完整表述。以飞机襟副翼装配的"作业—资源流图"为基础,介绍了装配生产率、资源利用率以及资源配置方案的分析与优化过程,验证了方法的有效性。     

一种数字化装配工艺设计系统的装配建模方法

分析Pro/E数字化装配工艺设计系统对装配模型的信息需求,在此基础上建立适合该装配工艺设计系统的基于约束层次结构的装配信息模型.最后详细介绍装配模型信息的提取算法流程.     

基于关系对象Petri网的飞机装配系统模型快速构建方法

为支撑飞机装配系统分析与优化,提出了基于关系对象Petri网的装配系统模型快速构建方法.依据现场组织模式分析了装配作业单元分解结构,给出了装配系统关系对象Petri网的模型定义,建立了作业单元对象和关系的表示方法.以模型定义与表示为基础,阐述了装配元对象和逻辑对象模型的构建步骤与规则.采用对象简化网对模型状态空间进行压缩,并建立了基于线性不变量的模型特性验证方法.以某型飞机机翼装配单元为对象进行了实例分析,结果证明了该方法的有效性.     

基于造价和维修费用的系统可靠性指标分配方法

可靠性指标分配是人力、物力统一调度和合理运用的一个工程决策问题，是与工程系统造价、维修费用密切相关的。因此，在进行系统可靠性分配时，必须同时考虑工程系统的造价和维修费用。本文给出了工程系统造价与可靠度的关系式和系统维修费用期望值与可靠度的关系式，建立了考虑造价与维修费用的系统可靠性模糊优化分配数学模型，从一而提出了基于造价和维修费用的系统可靠性指标分配方法，并给出了该方法的工程应用算例。结果表明：本文方法科学合理、简单实用，具有一定的工程应用价值。     

A study on maintenance reliability allocation of urban transit brake system using hybrid neuro-genetic technique

For reasonable establishing of maintenance strategies, safety security and cost limitation must be considered at the same time. In this paper, the concept of system reliability introduces and optimizes as the key of reasonable maintenance strategies. This study aims at optimizing component’s reliability that satisfies the target reliability of brake system in the urban transit. First of all, constructed reliability evaluation system is used to predict and analyze reliability. This data is used for the optimization. To identify component reliability in a system, a method is presented in this paper which uses hybrid neuro-genetic technique. Feed-forward multi-layer neural networks trained by back propagation are used to find out the relationship between component reliability (input) and system reliability (output) of a structural system. The inverse problem can be formulated by using neural network. Genetic algorithm is used to find the minimum square error. Finally, this paper presents reasonable maintenance cycle of urban transit brake system by using optimal system reliability.     

串联系统可靠性分配的层次分析方法

可靠性分配本质上是一个工程决策问题,需要考虑的因素众多。这里针对其特点,应用层次分析法进行探索,提出了一种基于层次分析法的串联系统可靠性分配方法。     

基于仿真的装配生产线布局设计与优化

基于离散事件仿真技术(DES),对某装配生产线开展了基于仿真的布局设计及优化研究工作,建立该仿真系统的目的是在现有制造模式的基础上,进行不同类型的生产线布局仿真设计试验,提出了一个装配生产线布局解决方案,减少生产线劳动力需求,解决生产瓶颈问题.在分析典型制造零件的制造工艺和生产线现有设备的基础上,提出了直线型布局、U型...     

机器人柔性装配系统优化规划方法研究

本文提出了用基于并行思想的约束网络方法对机器人柔性装配系统进行建模,该建方法改变了传统装配系统的串行设计模式,能较好地利用并行工程概念对系统进行设计。在上述建模的基础上,探索了应用遗传算法求解全局优化问题的途 解决大规模系统 化设计问题提供了一个有效工具。     

基于层次链的产品装配过程建模方法

针对虚拟装配中装配过程模型信息表达不完整的问题,提出了一种基于层次链的产品装配过程建模方法.该方法引入装配任务和装配操作模型,通过粗粒度的装配任务与细粒度的装配操作相结合的装配过程建模,实现了虚拟装配中装配过程信息的完整性表达.该方法采用并行的装配操作,实现了对非线性装配过程的建模;引入调整零部件和拆卸零部件两种类型的装配任务,实现了对非单调装配过程的建模.此外,通过基于层次链的装配过程建模方法,实现了装配过程回溯、重做和回放等装配过程信息地管理和重用.最后自主开发了原型系统,并对相关算法进行了验证.     

基于系统可靠性的生产与维护计划联合决策

为准确构建生产系统中批量生产与设备维护之间的关联关系,以并行机系统产能受限批量计划问题为基础,提出并引入基于系统可靠性的预防性维护策略与成组维护策略,建立了以生产与维护总成本最小化为目标的生产计划与预防性维护联合决策模型,从而在保证系统生产效益的前提下优化系统的维护频率、减少系统中生产与维护的总成本。模型的求解采用基于产能约束松弛的拉格朗日松弛算法框架,并设计了基于移动平滑方法的构造启发式算法,以获得问题的可行解并协同优化系统生产和维护计划。数值实验表明,该模型能充分发挥并行机的协调能力,有效避免设备过度维护问题,从而降低生产与维护总成本,所设计的算法具有较好的求解性能。     

A type-2 fuzzy expert system based on a hybrid inference method for steel industry

In this paper, a novel type-2 fuzzy expert system for prediction the amount of reagents in desulfurization process of a steel industry in Canada is developed. In this model, the new interval type-2 fuzzy c-regression clustering algorithm for structure identification phase of Takagi–Sugeno (T–S) systems is presented. Gaussian Mixture Model is used to generate partition matrix in clustering algorithm. Then, an interval type-2 hybrid fuzzy system, which is the combination of Mamdani and Sugeno method, is proposed. The new hybrid inference system uses fuzzy disjunctive normal forms and fuzzy conjunctive normal forms for aggregation of antecedents. A statistical test, which uses least square method, is implemented in order to select variables. In order to validate our method, we develop three system modeling techniques and compare the results with our proposed interval type-2 fuzzy hybrid expert system. These techniques are multiple regression, type-1 fuzzy expert system, and interval type-2 fuzzy TSK expert system. For tuning parameters of the system, adaptive-network-based fuzzy inference system is used. Finally, neural network is utilized in order to reduce error of the system. The results show that our proposed method has less error and high accuracy.     

基于可靠性分析的机器人系统故障维修系统

用现场数据作为可靠性分析的重要依据,利用简化的可靠性模型,采用SQL Server2000数据库和面向对象的程序设计语言VC++6.0,设计开发了一套以可靠性为中心维修(RCM)的机器人系统故障维修系统,为机器人系统的故障诊断提供更加真实的现场数据和诊断知识,使企业对机器人系统管理与维修更系统、更科学。     

Multiple failure mode reliability modeling and analysis in failure crack propagation based on time-varying copula

The fatigue failure of crack structure is influenced by fracture failure and static strength failure in the process of its growth. And the correlation characteristics between them change with the crack growth, which brings difficulties to safety assessment. To solve this problem, we propose a reliability model of failure crack propagation (FCP) based on time-varying copula. Meanwhile, a dynamic parameter estimation is put forward to build the time-varying copula. First, a flexible mixed copula model was constructed, by means of linear weighted model, to describe the nonlinear dependence among failure modes. Then the time-varying correlation parameters of copula were obtained by maximum likelihood estimation and least square polynomial fitting. Therefore, the dynamic parameter estimation of copula was realized, and then we used the built time-varying copula model to solve the reliability of joint failure. Finally, a numerical example was provided to illustrate the feasibility and application of the built time-varying copula model.     

Improved reliability analysis method based on the failure assessment diagram

With the uncertainties related to operating conditions,in-service non-destructive testing(NDT) measurements and material properties considered in the structural integrity assessment,probabilistic analysis based on the failure assessment diagram(FAD) approach has recently become an important concern.However,the point density revealing the probabilistic distribution characteristics of the assessment points is usually ignored.To obtain more detailed and direct knowledge from the reliability analysis,an improved probabilistic fracture mechanics(PFM) assessment method is proposed.By integrating 2D kernel density estimation(KDE) technology into the traditional probabilistic assessment,the probabilistic density of the randomly distributed assessment points is visualized in the assessment diagram.Moreover,a modified interval sensitivity analysis is implemented and compared with probabilistic sensitivity analysis.The improved reliability analysis method is applied to the assessment of a high pressure pipe containing an axial internal semi-elliptical surface crack.The results indicate that these two methods can give consistent sensitivities of input parameters,but the interval sensitivity analysis is computationally more efficient.Meanwhile,the point density distribution and its contour are plotted in the FAD,thereby better revealing the characteristics of PFM assessment.This study provides a powerful tool for the reliability analysis of critical structures.     

基于纬度建模的钢铁企业成本系统建模方法

为准确表达客户需求、更好地与用户沟通并全面描述业务对象,提出了基于纬度建模的信息系统建模方法.该方法首先采用纬度模型描述用户需求,并采用IDEF0技术建立系统功能模型;针对纬度模型和多数据源建立IDEF1x模型,以指导数据库设计;通过统一建模语言技术对IDEF0中的节点进行业务链描述,并建立对象模型以指导软件系统设计.最后,以某钢铁企业的成本管理系统设计为例,通过分析成本管理业务模型,详细阐述了该建模方法对成本管理系统的设计过程的支持.实际应用证明了该方法的有效性和可行性.     

A hybrid assembly sequence planning approach based on discrete particle swarm optimization and evolutionary direction operation

Assembly sequence planning (ASP) has always been an important part of the product development process, and ASP problem can usually be understood as to determine the sequence of assembly. A good assembly sequence can reduce the time and cost of the manufacturing process. In view of the local convergence problem with basic discrete particle swarm optimization (DPSO) in ASP, this paper presents a hybrid algorithm to solve ASP problem. First, a chosen strategy of global optimal particle in DPSO is introduced, and then an improved discrete particle swarm optimization (IDPSO) is proposed for solving ASP problems. Through an example study, the results show that the IDPSO algorithm can obtain the global optimum efficiently, but it converges slowly compared with the basic DPSO. Subsequently, a modified evolutionary direction operator (MEDO) is used to accelerate the convergence rate of IDPSO. The results of the case study show that the new hybrid algorithm MEDO-IDPSO is more efficient for solving ASP problems, with excellent global convergence properties and fast convergence rate.     

基于事故树方法的人机系统可靠性分析

针对提高人机系统设计的可靠性,将事故树分析方法应用到人机系统设计可靠性分析中去,从人的角度对人机系统设计的可靠性进行了事故树分析,首先找出了事故树的最小径集,然后又分别从结构重要度、概率重要度、关键重要度等方面对影响人机系统可靠性的基本事件进行了分析研究,找出了影响人机系统可靠性的主要因素,为人机系统产品的设计生产提供...