面向产品方案决策的层次分析改进算法研究

产品方案决策是一个复杂的多目标决策问题 ,层次分析法 (AHP)是解决这个问题的有效方法。本文在研究AHP产品决策方法的基础上 ,分析了 AHP算法的局限性 ,提出了利用判断矩阵本身的元素和主特征向量来改进判断矩阵一致性的算法 ,并用实例证明了该算法的有效性。     

基于改进AHP的多供应商选择问题研究

针对供应链管理环境下的多供应商选择的多目标问题,考虑了采购量折扣和供应商能力约束。在应用粗糙集理论的基础上,对传统AHP进行了改进,量化了定性因素,建立了以价格、质量和服务为目标函数,以供应能力、及时运送等为约束条件的多目标混合整数规划模型,采用最大权值,最优化方法得到问题的最优解,仿真实例验证了该模型与求解方法是现实可行的。     

基于熵权与层次分析法的机床再制造方案综合评价

结合机床再制造实践,建立了包括经济性、技术性、资源性、环境性的机床再制造方案综合评价指标体系,并对各个指标的量化方法进行了分析;提出了一种基于熵权与层次分析法的机床再制造方案综合评价方法。通过在某企业车床再制造中的应用,验证了所提方法的有效性。     

机床设备选择模型建立及综合评价

应用模糊综合评价理论建立数学模型来评价数控机床,使这种评价科学,实用。     

基于面向对象和数据库技术的机床选择专家系统

机床选择是机械加工工艺设计中的一个重要环节。专家系统是人工智能的一个主要研究方向,非常适合处理需要大量经验知识的设计问题。提出将面向对象方法和数据库技术相结合,进行了机床选择专家系统总体结构设计,并介绍了各模块对应的功能,研究了基于产生式规则的知识表示方法、基于关系型数据库的知识库的管理和基于正向推理方式的推理机的设计和推理过程等关键技术,以Visual C++和Access为开发工具,实现了机床选择专家系统。     

基于AHP与模糊多目标规划的新产品组合研究

分析了新产品组合方法对产品开发的重要作用，提出了基于AHP与模糊目标规划的新产品组合方法，将人的经验判断与客观分析相结合，经过实例计算，取得了满意的结果。     

某机床的可维修性研究

以一牛头刨床为例,建立了其失效的概率模型,论述了机床可靠性维修的理论,探讨了机床的最佳维修周期的界定问题及计算方法。     

加工中心盘式刀库自动换刀控制系统设计

针对自主研发制作的微型盘式刀库加工中心,阐述了其具体的换刀过程,提出了一条基于单片机的自动换刀控制方案;重点介绍了通信和PWM脉冲输出等外围电路;IO电路中采用光隔,提高了系统的稳定性.该方案根据模块化的思想把自动换刀控制系统作为一个独立的单元进行设计,并通过RS232和数控系统进行通信,降低了对数控系统的依赖性,结构简单,成本低,通用性好,并通过多次重复试验验证了其稳定可靠性.     

模糊综合评价法在机床产品协同设计中的应用

在复杂产品的协同设计过程中,常常会遇到难于确定的多个设计方案,需要多领域专家集体评价.为保证异地专家网上评价的准确性,研究机床产品的模糊综合评价法,建立简化的数控车床概念设计评价模型,并以某一数控车床为对象,给出应用实例,为机床产品的协同设计方案提供了评价工具.     

An integrated fuzzy approach for the selection of manufacturing technologies

In this paper, an integrated decision support system is developed, which employs fuzzy techniques to assist decision-makers in choosing an optimal solution from alternative manufacturing options in an uncertain environment. The integrated approach incorporates different justification methods (e.g., strategic, economic, and analytic evaluations) for assessing tangible benefits, like cost, and intangible benefits, like quality, of different alternatives by a fuzzy multi-criteria decision-making method. As an illustrative example, selection of different advanced manufacturing technologies has been demonstrated by using the proposed methodology. The proposed concept will greatly reduce conflicts between tangible and intangible factors, and enhance the process of identification, interpretation, and diagnosis of the value of complex manufacturing and engineering systems.     

Optimization of measuring points for machine tool thermal error based on grey system theory

Optimization of thermal sensors’ placement on machine tools based on grey correlation model of grey system theory is studied. After optimization, the temperature variables in the thermal error’ model are reduced from 16 to 4. It greatly reduces the time for variable searching and modelling and meanwhile it eliminates the coupling problems among temperature variables, so the robustness of the model could be increased and the predicting precision of the model is enhanced. Consequently, the real-time error compensation would be more effective and convenient.     

旋锻机锻模头的运动分析

通过分析旋锻机锻头的运动发现传统锻头的不足,利用凸轮轮廓线设计等知识将原锻头结构加以改进后,再运用高等数学的积微分原理将改进后锻头的运动轨迹画出并进行分析,从而得出改进后的锻头结构,能够使对物料的瞬时打击力增大,最终实现提高加工工件时的工作效率和加工精度的目的.     

Development of meso-scale milling machine tool and its performance analysis

To overcome the shortcomings of current technologies for meso-scale manufacturing such as MEMS and ultra precision machining, this paper focuses on the investigations on the meso milling process with a miniaturized machine tool. First, the related technologies for the process mechanism studies are investigated based on the analysis of the characteristics of the meso milling process. An overview of the key issues is presented and research approaches are also proposed. Then, a mesoscale milling machine tool system is developed. The subsystems and their specifications are described in detail. Finally, some tests are conducted to evaluate the performance of the system. These tests consist of precision measurement of the positioning subsystem, the test for machining precision evaluation, and the experiments for machining mechanical parts with complex features. Through test analysis, the meso milling process with a miniaturized machine tool is proved to be feasible and applicable for meso manufacturing. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(11): 162–167 [译自: 机械工程学报]     

数控机床位移误差的研究

数控机床的位移误差是影响其加工精度的重要指标,这里基于这样的观点进行理论分析和试验,列出了位移误差的来源及影响因素,推导了位移误差模型、进行了误差分类,试验结果表明误差模型的准确性和补偿方法的实用性。     

并联机床数控系统软件设计

结合3-HSS并联机床结构特点,确定了采用以“PC 适配器”为硬件平台,以Windows操作系统为软件平台建造样机的开放式数控系统的总体方案,并介绍了数控系统控制结构和系统软件各模块的设计。     

基于失效树分析的机床进给系统可靠性设计

超精密机床系统可靠性的问题日益受到重视,失效树分析法可以帮助设计者及早有效地评价设计中存在的薄弱环节及缺陷,以此来改进设计,可以提高产品的可靠性水平.本文以超精密车床进给系统为例,建立系统可靠性模型,通过失效树分析找出系统的相对薄弱环节,并提出提高机床系统可靠性的措施,获得了良好的效果.     

Selecting human machine interface package in integrating a process automation system

In this paper we propose a framework for evaluating and selecting human machine interface (HMI) packages in integrating a process automation system. HMIs are among main subsystems of many integrated process automation systems. The main objective of this paper is to propose a selection process so that the integrated system could better satisfy strategic goals of the system users. In this paper we assume that strategic goals are expressed in terms of concepts like production flexibility, production reliability, product quality, operation cost, production time and the like.     

Thermal error compensation of a 5-axis machine tool using indigenous temperature sensors and CNC integrated Python code validated with a machined test piece

Achieving high workpiece accuracy is the long-term goal of machine tool designers. There are many causes for workpiece inaccuracy, with thermal errors being the most common. Indirect compensation (using prediction models for thermal errors) is a promising strategy to reduce thermal errors without increasing machine tool costs. The modelling approach uses transfer functions to deal with this issue; it is an established dynamic method with a physical basis, and its modelling and calculation speed are suitable for real-time applications. This research presents compensation for the main internal and external heat sources affecting the 5-axis machine tool structure including spindle rotation, three linear axes movements, rotary C axis and time-varying environmental temperature influence, save for the cutting process. A mathematical model using transfer functions is implemented directly into the control system of a milling centre to compensate for thermal errors in real time using Python programming language. The inputs of the compensation algorithm are indigenous temperature sensors used primarily for diagnostic purposes in the machine. Therefore, no additional temperature sensors are necessary. This achieved a significant reduction in thermal errors in three machine directions X, Y and Z during verification testing lasting over 60 h. Moreover, a thermal test piece was machined to verify the industrial applicability of the introduced approach. The results of the transfer function model compared with the machine tool's multiple linear regression compensation model are discussed.     

基于PMAC的开放式组合机床控制系统开发

利用VB开发上位机的控制程序界面,设计了一种基于可编程多轴控制器PMAC的开放式组合机床控制系统.通过对PMAC多轴控制器的硬件构建及运动程序、PLC程序等的软件编写,完成了针对组合机床的开放式控制系统开发.     

基于参数化的机床产品快速变型设计

在产品的概念设计过程中,融入参数化技术,实现大规模定制化产品的快速设计.针对机床产品,以UG为软件平台,结合V C 和SQL Server数据库开发机床产品参数化变型系统,并讨论从功能需求到结构参数模型的映射过程、主要结构特征尺寸参数化等关键技术,通过参数化实现产品级的机床快速变型设计.