基于PDM的工艺知识库管理方法研究

为了完成基于产品数据管理的计算机辅助工艺设计系统中工艺知识库管理系统的开发,提出了一种基于产品数据管理的工艺知识库管理方法。工艺知识包括工艺资源信息、工艺实例和工艺决策知识三类,据此构建了基于产品数据管理的工艺知识库管理系统的体系结构,提出了基于物料清单的工艺实例表示方法和检索方法、基于数据库中view技术的工艺资源信息的检索方法和基于工艺决策知识三视图模型的工艺决策知识库的维护策略。最后,介绍了样机系统的应用。     

基于Web的数字现场工艺纪律管理系统的开发

阐述企业现场工艺纪律管理的主要内容,提出现场工艺纪律管理的评价指标体系,建立模糊综合评价模型.利用ASP.NET技术开发出一套基于Web的现场工艺纪律管理系统,对系统的体系结构、功能特点进行介绍.     

典型回转体零件工艺知识库系统的研究

分析了典型回转体零件工艺知识的表示方式及存储组织形式,阐述了该实用系统的规划和设计,介绍了零件工艺知识的录入、修改、查询方法及其实现.     

面向知识管理的过程企业知识模型体系研究

过程企业由于其特定的技术经济形态,由单元生产过程和市场需求协同作用,驱动决策流成为其知识管理显著的特点和难点。分析了过程企业由动态过程模拟模型、过程控制模型、技术经济评价及经营决策模型构成的三级过程性知识模型体系,提出静态性知识、策略性知识和推理性知识的知识分类方法,解决了过程企业实施现代集成过程系统必须的基于市场需求和生产过程的决策模型。研究并提出了基于类的面向对象的知识模型表达模式,形成由模型类、模型框架和模型实例构成的模型层次,讨论了以过程模拟和数据挖掘作为重要技术支撑的知识学习方法,并针对行业的过程性特点,提出了面向业务与决策过程的知识发布模式。     

Development of an online machining process monitoring system: a case study of the broaching process

This paper presents a new online machining process monitoring system based on the PXI hardware platform and the LabVIEW software platform. The whole system is composed of the following interconnected packages: sensing, triggering, data acquisition, characterisation, condition monitoring and feature extraction packages. Several signal processing methods, namely, cross-correlation, resample, short-time Fourier transform (STFT) and statistical process control, are developed to extract the features of tool malfunctions and construct the thresholds of malfunction-free zones. Experimental results show that the developed online process monitoring system is efficient for acquiring, analysing and presenting sensory signals simultaneously, while the developed signal processing techniques are effective for detecting tool wear and constructing thresholds for tool-malfunction-free zones. Additionally, a sensitivity analysis of the signals acquired from alternative sensors versus those collected from a dedicated platform dynamometer has been carried out. This enables the evaluation of the possibility to employ alternative sensing techniques in an industrial environment.     

机械制造工艺学多媒体教学软件的研制

基于所开发的机械制造工艺学多媒体教学 (CAI)软件 ,重点介绍软件开发的前期准备工作、软件总体结构框架设计以及软件的运行与测试等主要环节。本软件已研制完成并投入使用     

Design of an analytic-hierarchy-process-based expert system for non-traditional machining process selection

The selection of a non-traditional machining (NTM) process is often observed to be a multi-criteria decision-making problem with conflicting and diverse objectives. This paper presents a systematic methodology for selecting the best or optimal non-traditional machining process under constrained material and machining conditions. The paper also includes the design of an analytic-hierarchy-process-based expert system with a graphical user interface to ease the decision-making process. The developed expert system relies on the priority values for different criteria and sub-criteria, as related to a specific non-traditional machining process selection problem. It also depends on the logic table to discover the non-traditional machining processes that lie in the acceptability zone, and then selects the optimal process having the highest acceptability index value. The proposed expert system can automate the selection of a non-traditional machining process and provide artificial intelligence in the multi-criteria decision-making process.     

机床加工系统切削热全过程传递模型研究

经典切削热研究主要考虑了切削区热量的发生机理及其在切屑、工件、刀具之间的分配。综合考虑切削热在切屑、工件、刀具、冷却介质以及机床加工空间的传递规律,提出了机床加工系统切削热三阶段传递的新思路。从热传递框图模型及热传递计算模型2个层面,分别建立了切削接触界面热传递动态模型、切削区域热传递动态模型、机床加工空间热传递动态模型。最后通过现有文献试验数据对比对所建模型的置信度进行了分析。该模型的建立将为切削热的理论研究提供新的研究思路,为刀具寿命和机床加工系统温度场控制技术提供理论支撑。     

XML在工艺知识管理系统中的应用

介绍XML语言的基本概念和主要优点,开发出面向企业网络环境的工艺知识管理系统的原型系统。利用一个实例具体分析XML在该系统中的应用,最后展望XML应用于企业信息化建设的发展前景。     

基于多Agent的流程企业动态设备管理业务系统

为适应流程企业对现场设备管理的新要求,提出了基于多Agent技术构筑动态设备管理业务系统。作为现场生产设备预知维护体系的顶层部分,动态设备管理业务系统通过设备Agent的即插即用实现了可重构,从而适应了企业组织结构和设备管理体制动态变化的需要。设备Agent基于软件组件进行开发,通过说明性的属性配置实现了自身调整。基于多Agent技术的动态设备管理业务模型,为流程企业的设备管理提出了建设性的意见。     

基于信息融合技术的加工过程监测系统研究

加工过程状态的监测与控制是提高机床智能化的重要研究内容,为实现加工过程的智能化监测与控制必须以多传感器及多传感器信息融合技术为基础.提出了一种基于粗糙集理论和神经网络的多传感器智能信息融合方法,该方法将粗糙集理论作为实现多传感器数据融合的方法,同时针对粗糙集理论只能处理离散数据的问题.提出了使用自组织特征映射网络对传感器采集数据进行离散化及聚类处理的方法,针对粗糙集理论在决策融合处理方面的不足,提出了使用BP神经网络来实现决策规则的有效融合,分析了该方法的原理、关键技术及实现方法,为后期的进一步的研究和应用打下基础.     

产品工艺信息管理与过程仿真集成系统的研究

利用动态服务器网页技术,结合过程仿真工具,研发了基于浏览器/服务器三层网络体系结构的产品工艺信息管理与过程仿真集成系统。该系统包括产品结构管理、产品工艺卡片管理、产品图文档/说明文档管理以及产品工艺过程仿真管理四个子系统。详细介绍了系统的体系结构、功能以及实现的关键技术。     

基于RFID的加工中心刀具信息管理系统的研究

针对刀具管理的现状,提出一种面向加工中心的RFID刀具信息管理系统。分析了加工中心对刀具信息的需求,采用RFID自动识别技术标识刀具,将刀具关键信息存储在RFID芯片中,并以西门子840D数控系统为例,通过OEM(Original Equipment Manufacture)二次开发软件连接射频处理器与数控系统,实现加工中心刀具信息的自动输入与更新。提高了刀具参数输入的效率与准确性,有效地降低了刀具准备时间与出错率。     

面向CIMS的车间管理信息系统的开发

车间管理信息系统(M IS)是企业C IMS系统的基本组成部分。结合为某大型企业的某个核心生产车间开发生产管理系统的实际过程,阐述开发的一般方法和流程,具体讨论开发过程中所涉及到的系统目标分析、整体设计、系统功能实现以及安全性方面所采取的措施。     

A flexible process information reuse method for similar machining feature

Dynamically changing machining conditions and uncertain manufacturing resource availability are forcing manufacturing enterprises to search advanced process planning in order to increase productivity and ensure product quality. As growing quantities of the three-dimensional process models are gradually applied, reusing the embedded manufacturing information in process models with less time and lower cost attracts a lot of attention. In this paper, a new flexible method is presented to reuse the existing process information based on retrieval of the similar machining feature. First, the three-level organization model is introduced to represent the process information; the machining feature which is seen as the parent layer carries the corresponding manufacturing information. To ensure accurately that the process information are obtained, the associated mechanism between the machining feature and process information is created. Second, an eight-node representation scheme is designed to represent the similar machining feature having same variations in topology and geometry. For accelerating similar feature retrieval, the extension-attributed adjacency graph and the topological relationship of the machining feature faces are built. Finally, some aircraft structural parts are utilized in the developed prototype module to verify the effectiveness of the proposed method. This method can be used as the basis for accumulation of the process information; it can promote the development and application of the intelligent process planning.     

Development of an intelligent process model for EDM

This paper reports the development of an intelligent model for the electric discharge machining (EDM) process using finite-element method (FEM) and artificial neural network (ANN). A two-dimensional axisymmetric thermal (FEM) model of single-spark EDM process has been developed based on more realistic assumptions such as Gaussian distribution of heat flux, time- and energy-dependent spark radius, etc. to predict the shape of crater cavity, material removal rate, and tool wear rate. The model is validated using the reported analytical and experimental results. A neural-network-based process model is proposed to establish relation between input process conditions (discharge power, spark on time, and duty factor) and the process responses (crater geometry, material removal rate, and tool wear rate) for various work—tool work materials. The ANN model was trained, tested, and tuned using the data generated from the numerical (FEM) simulations. The ANN model was found to accurately predict EDM process responses for chosen process conditions. It can be used for the selection of optimum process conditions for EDM process.     

基于知识网络系统的企业知识管理过程支持模型

针对如何利用知识网络系统支持企业知识管理的问题,分析企业对知识的需求,给出了企业知识网络形式化定义,并将知识网络分为组织知识网络、个体知识网络和业务流程知识网络.提出了知识网络系统的构方法,以及知识网络系统的层次模型和各组成部件的功能描述,并深入研究了构建知识网络的关键处理过程和算法.在此基础上,提出了基于知识网络系统的企业知识管理过程支持模型.通过研究企业知识网络系统的构建方法及其过程支持模型,可揭示企业的知识存在、需求和发展情况,为企业实现知识的高效应用和有效管理提供有力的支持.最后,通过一个航空企业实际案例,说明了该方法的可用性.     

钢卷(板)包装工艺知识管理系统的研究和构建

为有效解决钢板(卷)包装工艺规划管理问题,对包装过程中涉及到的钢材(卷)、包装材料、包装生产线、包装工具、包装辅具、包装设备等资源,以及各种包装工艺经验和实例进行系统的分析研究,提出了构建其数据库、知识库管理系统的组织架构,以VC++、SQLServer2005为工具开发了包装工艺知识管理系统,实现了对钢板包装过程所涉及到的工艺信息和工艺知识进行检索、管理、再生和应用。     

Development of multi-objective optimization models for electrochemical machining process

Owing to the complexity of electrochemical machining (ECM), it is very difficult to determine optimal cutting parameters for improving cutting performance. Hence, optimization of operating parameters is an important step in machining, particularly for unconventional machining procedures like ECM. A suitable selection of machining parameters for the ECM process relies heavily on the operator’s technologies and experience because of their numerous and diverse range. Machining parameters provided by the machine tool builder cannot meet the operator’s requirements. Since for an arbitrary desired machining time for a particular job, they do not provide the optimal conditions. To solve this task, multiple regression model and ANN model are developed as efficient approaches to determine the optimal machining parameters in ECM. In this paper, current, voltage, flow rate and gap are considered as machining parameters and metal removal rate and surface roughness are the objectives. Then by applying grey relational analysis, we calculate the grey grade for representing multi-objective model. Multiple regression model and ANN model have been developed to map the relationship between process parameters and objectives in terms of grade. The experimental data are divided into training and testing data. The predicted grade is found and then the percentage deviation between the experimental grade and predicted grade is calculated for each model. The average percentage deviations for the training data of the linear regression model, logarithmic transformation model, excluding interaction terms and ANN model, are 12.7, 25.6 and 3.03, respectively. The average percentage deviations for the testing data of the three models are 9.83, 26.8 and 2.67. While examining the average percentage deviations of three models, ANN is having less percentage deviation. So ANN is considered as the best prediction model. Based on the testing results of the artificial neural network, the operating parameters are optimized. Finally, ANOVA is used to identify the significance of multiple regression model and ANN model.     

可拓知识表示及知识库系统的开发

针对现有知识表示方法在智能设计中的局限,提出了一种基于可拓模型的知识表示方法.给出了该方法的定义、语法规范和存储结构.详细论述了基于可拓知识表示的菱形求解策略.包括可拓约束图的构建、物元拓展推理、关联函数计算和条件可拓集合的生成;开发了基于可拓知识表示及菱形求解策略的知识库系统.将该系统应用于水轮机选型设计,得到了比基于规则知识库系统更合理的结果,初步证明了可拓知识表示在解决智能设计知识表示问题时的可行性.