面向用户的柔点柔变范围定量度量技术

为了解决柔性软件柔点柔变范围度量准确性差和操作性低的问题,以面向用户的柔点为研究对象,提出了软件柔变性模型,建立了柔点变化传播影响图,改进了功能点分析法,给出了柔点柔变范围定量度量模型。在该度量模型中,以柔变部件作为基本度量实体,利用柔变性模型表示柔点、柔变点和柔变项,通过柔点变化传播影响图分析柔点变化传播影响,应用改进的功能点分析法提取软件柔点变化影响的柔变部件,进而计算所有柔变部件的功能点计数,确定柔点柔变范围的定量值。结合实例说明了柔点柔变范围的定量度量过程,分析了柔点柔变范围。     

基于柔性铰链的柔性放大机构参数化设计

为了对柔性微位移放大机构进行优化设计,有必要对柔性铰链及柔性放大机构进行参数化分析与研究。提出了一个通用的结构参数ε,探讨了ε对不同柔性铰链柔度系数的影响规律,并横向比较了常用柔性铰链的柔度特性。另一方面,基于柔度特性的影响分析,提出了新的参数柔度比λ,重点分析了不同柔度比λ的柔性铰链主要输出位移形式的灵敏度。以实际的桥式柔性微位移放大机构为例,利用参数ε和λ实现了该柔性放大机构的参数化设计,并用有限元软件进行了仿真计算。实验测量结果表明,对基于柔性铰链的柔性微位移放大机构进行参数化设计,最终输出位移行程与有限元仿真设计的结果误差率为3.80%。基于柔性铰链的结构参数ε和柔度比λ对柔性放大机构进行参数化设计是可行且正确的,有利于这一类柔性放大机构的优化设计。     

空间曲线切口式柔性铰的设计

为了满足精密仪器连接部件的柔度和强度需求,以切口曲线为二次曲面和圆柱面的相贯线的柔性铰为例,研究了一类空间曲线切口式柔性铰的设计方法。推导了此类柔性铰转动柔度的一般设计计算公式,分析了设计参数对柔度特性的影响,在此基础上提出了此类柔性铰的设计方法。依据提出的方法设计了空间曲线切口式柔性铰,并利用有限元分析方法对设计实例进行了柔度和强度校核,同时建立了模态实验系统识别其柔度。结果表明,两种柔度校核结果与设计计算公式结果吻合较好,最大误差不超过5%,验证了设计方法的有效性,为此类柔性铰应用于精密仪器的工程设计提供了参考。此外,文中给出的有限元建模分析方法以及试验测试方法也可用于相同类型的精密构件的力学特性研究与分析。     

柔性冗余度机器人的可操作性柔度的研究

把机器人操作器的杆件的柔度按照势能等效原理附加杆件的伺服关节柔度上,称为等效关节柔度;利用操作器的关节空间和直角坐标的空间的对偶关系,得到操作器末端的等效柔度矩阵,并提出了综合柔度的概念,以表明操作器末端柔度大小;结合冗余度机器人操作器的可操作性能,提出了在柔性冗余度机器人中操作器的柔性和可操作性对其性能的综合影响指标－－可操作性柔度。通过调整冗余度机器人的“自运动”最小化可操作性柔度,从而取得具有较低的柔性和较好的操作性能的操作器的最佳工作姿态,为柔性冗余度机器人的控制提供了依据。     

柔性冗余度机器人的可操作性桑度的研究

把机器人操作器的杆件的柔度按照势能等效原理附加到杆件的伺服关节柔度上,称为等效关节柔度;利用操作器的关节空间和直角坐标空间的对偶关系,得到操作器末端的等效柔度矩阵,并提出了综合柔度的概念,以表明操作器末端柔度大小;结合冗余度机器人操作器的可操作性能,提出了在柔性冗余度机器人中操作器的柔性和可操作性对其性能的综合影响指标——可操作性柔度。通过调整冗余度机器人的"自运动"最小化可操作性柔度,从而取得具有较低的柔性和较好的操作性能的操作器的最佳工作姿态,为柔性冗余度机器人的控制提供了依据。     

典型柔性铰链转角柔度对比分析

柔性铰链结构广泛的应用于精密定位系统中,利用卡氏第二定律推导了柔性铰链的通用转角柔度计算公式。引入两个无量纲参数,通过将典型柔性铰链的柔性部位的边沿曲线表述为圆锥曲线形式,建立了含有共同参数的典型柔性铰链的转角柔度计算公式,采用有限元法对所建立的转角柔度公式进行了验证。在此基础之上,以圆形柔性铰链的转角柔度为基准,定义了转角柔度比函数,对比分析了典型柔性铰链的转角柔度特性,为确定大行程柔性机构设计时的基本变形单元提供了理论依据。     

基于闭环柔度解析式的双曲线形柔性铰链研究

提出了一种新型的单轴柔性铰链结构型式一单边双曲线形柔性铰链。以力学卡氏第二定理和微积分为理论基础，推导了单边双曲线形柔性铰链柔度的闭环解析公式，在此基础上，推导出单边双曲线形柔性铰链的转动精度公式，对单边双曲线形柔性铰链的性能进行分析，得出了结构参数对其柔度性能的影响关系。并通过对双边双曲线形柔性铰链比较，分析了单边双曲线形柔性铰链的转动能力、转动精度和对轴向载荷的影响等性能，利用有限元和实验的方法对单边柔性铰链的柔度公式进行校验，结果表明有限元与闭环解析式的偏差小于8％，实验结果和解析式的偏差在7％以内，为柔性铰链在结构紧凑、大位移场合的工程应用提供了有价值的参考。     

基于有限元法的单边混合柔性铰链的性能分析

提出一种新型的单轴柔性铰链结构型式-单边混合柔陛铰链,由半个直圆柔性铰链和半个导角柔性铰链构成.通过有限元方法,分析了一组不同导角半径的单边混合铰链设计实例,结果表明单边该混合柔性铰链相对于一般混和柔性铰链与单边柔性铰链具有更高的柔度.并得到其柔度应力比,可用于定量地比较各种柔性铰链的性能差异.提出的单边混合柔性铰链为面向结构紧凑、大位移、高精度的工程应用提供了有价值的参考.     

混合型柔性铰链研究

提出一种新型的单轴柔性铰链结构型式--混合柔性铰链,它由半个直圆柔性铰链和半个导角柔性铰链构成.提出了柔度应力比这一概念,为定量地比较各种柔性铰链提供了依据.通过有限元方法,分析了一组不同导角半径的混合铰链设计实例,并得到其柔度应力比值.结果表明该混合柔性铰链的性能远高于直圆柔性铰链.设计的混合柔性铰链为面向高精度、大位移的工程应用提供了有价值的参考.     

3自由度柔性微机器人的静刚度分析

柔性微机器人要求具有很高的定位精度，而其静刚度在很大程度上决定着这一指标。针对目前对柔性微机器人静刚度分析中存在的不足，采用了结构分析中的柔度矩阵法：首先建立起机构中柔性单元的柔度模型，同时通过不同坐标系间的转换和单元节点处位移协调方程和力平衡方程的建立，递推出机器人末端相对参考坐标系下的静刚度矩阵。最后，以3自由度并联柔性微机器人为实例分析了该机器人的静刚度。分析表明：利用柔度矩阵法分析柔性微机器人运动学问题不仅便于计算，更接近柔性机构的本质。     

An Evaluative Study of Operation Grouping Policies in an FMS

The increased use of flexible manufacturing systems to provide customers with diversified products efficiently has created a significant set of operational challenges for managers. This technology poses a number of decision problems that need to be solved by researchers and practitioners. In the literature, there have been a number of attempts to solve design and operational problems. Special attention has been given to machine loading problems, which involve the assignment of job operations and allocation of tools and resources to optimize specific measures of productivity. Most existing studies focus on modeling the problem and developing heuristics in order to optimize certain performance metrics rather than on understanding the problem and the interaction between the different factors in the system. The objective of this paper is to study the machine loading problem. More specifically, we compare operation aggregation and disaggregation policies in a random flexible manufacturing system (FMS) and analyze its interaction with other factors such as routing flexibility, sequencing flexibility, machine load, buffer capacity, and alternative processing-time ratio. For this purpose, a simulation study is conducted and the results are analyzed by statistical methods. The analysis of results highlights the important factors and their levels that could yield near-optimal system performance.     

单轴对称柔性铰链计算机辅助设计系统

柔性铰链性能的好坏直接影响到微位移机构的精度、稳定性和耐久性.目前微位移机构正在向着高精度、微型化的方向发展,对柔性铰链的性能也提出了越来越高的要求.针对柔性铰链传统手工设计方法费时、费力、且精度不高的缺点,基于Visual Basic(VB)语言开发了一套单轴对称柔性铰链计算机辅助设计系统,圆形铰链实例计算表明:该系统实现了单轴对称柔性铰链设计与校验自动化,大大提高了设计效率和设计质量.计算得到的铰链柔度/旋转精度曲线组,不仅可用于考察符合设计要求的数据组,而且清晰地反映了铰链几何参数与其柔度、旋转精度间的关系,为下一步进行柔性铰链理论分析提供了有力的工具,为可靠、高效微位移系统的建立提供了良好的基础.     

漂浮基带柔性铰空间机器人的动力学建模及奇异摄动控制研究

探讨了本体位置与姿态均不受控制情况下,漂浮基带一般柔性铰空间机器人的动力学建模与奇异摄动控制问题。结合系统线动量及角动量守恒关系,通过拉格朗日法建立了系统的动力学模型。为解除传统奇异摄动控制技术应用受关节柔性的限制,引入了一种关节柔性补偿器,以等效降低系统各关节铰的柔性。之后借助于奇异摄动理论,先后设计了漂浮基带柔性铰空间机器人关节空间、惯性空间期望运动轨迹跟踪的奇异摄动控制方案。该控制方案无关节柔性的限制,因此较适用于具有一般柔性铰空间机器人系统的控制。理论分析及仿真试验结果均表明控制方法可行。     

Manufacturing Flexibility: Assessing Managerial Perception and Utilization

This paper presents an empirical study of how consumer electronics companies in Brazil deal with the issue of manufacturing flexibility. The main purpose is to provide an understanding into how flexibility is being perceived and utilized in a newly industrialized country. It begins by explaining the relevance of this study. The participation of Brazil in the world economy is important. Here, companies can be very flexible, based on low cost and an abundant skilled work force, yet flexibility has not been addressed. The paper explains how indicators were established to obtain an analytical structure with which to assess the managerial perception and the actual industrial use of flexibility. Finally, we show the most relevant results of our investigation of 16 leading firms in Brazil, including multinational ones. The findings are divided according to managerial perception of flexibility and effective utilization of flexibility in the organization. The paper concludes that firms in the consumer electronics industry in Brazil do not use flexibility practices in the same proportion that they perceive its importance.     

高铁车厢柔性预装配平台设计研究

针对高铁车厢预装配不可重用、柔性差及自动化程度低等问题,对高铁柔性预装配进行了研究,提出了由内外龙门及相应的机械手组成的预装配平台,内龙门机械手通过外龙门机械手提供动力实现了位置移动及装配点的定位。通过开发基于台达触摸屏和PLC分布式控制系统,实现了PLC控制程序和人机界面软件相结合的柔性预装配控制。通过上位机软件的规划及管理最终实现了预装配过程的自动化及智能化。现场试验结果表明,该系统实现了真实模拟车厢装配环境、准确定位车厢内关键零部件的位置,根据车厢情况灵活配置实现了柔性装配等多项功能,具有一定的实用性及推广价值。     

On the Consequences of Information Delays in the Scheduling of Semi-Automated Flexible Machines

Manufacturing systems with varying levels and types of flexibility employ alternative scheduling strategies to exploit flexibility for performance enhancement. Scheduling decisions in manufacturing systems are influenced by time delays due to information handling activities such as information collection, transfer, and processing. More specifically, scheduling strategies implicitly involve information intensive activities that may entail significant time delays for implementation, depending on the extant shop floor automation and integration within a flexible system. These are information delays and we believe that most contemporary flexible systems must inherently cope with some level of information delay when implementing on-line scheduling strategies. This paper conceptualizes the manifestation of information delays in the context of scheduling decisions within flexible systems through the definition of three key delay modes: (i) Mode 1 information-transfer delay; (ii) Mode 2 decision-implementation delay; and (iii) Mode 3 status-review delay. We then stress the need and importance of devising suitable on-line scheduling strategies for countering the effect of information delays by demonstrating the efficacy of a novel scheduling strategy on a single machine. While opening a new scheduling dimension with potential research ramifications, this paper highlights the fact that the concept of information delay can effectively capture the synergism issues related with flexibility, integration, and automation in the context of scheduling decisions within semi-automated flexible systems.     

基于Petri网的产品研发设计工作流的柔性建模方法

为了解决复杂产品研发设计工作流建模问题,提高产品研发设计工作流管理系统在运行中对动态变化的响应能力,提出了一种基于Petri网的柔性建模方法。该方法结合面向对象和分层的思想对Petri网进行扩展,利用优先级、变迁触发规则等属性规则描述了模型的柔性。该方法不仅可以降低产品研发设计工作流建模的复杂度,还可以支持产品研发设计工作流管理系统对资源调度、动态选择和异常响应的柔性控制。最后通过一个实例说明了该方法的可行性。     

柔性结构拓扑优化设计发展概况

论述了柔性结构的特点、拓扑优化设计的基本原理与方法、国内外研究发展现状 ,以及在工程设计中的应用等问题。最后 ,列出了柔性结构拓扑优化设计的发展方向、需要解决的问题 ,以及可能解决的方案等。     

Machine Sharing in Manufacturing Systems: Total Flexibility versus Chaining

In this paper, we compare the operational performance of two machine-sharing configurations: total flexibility and chaining. We show that chaining captures most of the benefits of total flexibility while limiting the number of part types processed on any individual machine to only two. We examine the relative desirability of the two configurations under varying buffer sizes, loading conditions, number of machines, and setup times, as well as for different control policies. For nonzero setups times, we show that chained configurations can outperform fully flexible ones. This particularly is the case when either the number of machines or length of setup times is high. We also find that the effect of the system size on performance diminishes with the number of machines. This means that multiple smaller chains can perform almost as well as a single long one. Our results are consistent with the recent findings of Jordan and Graves (1995), who examined the economic benefits of chaining relative to full flexibility.     

Mass Customization in Videotape Duplication and Conversion: Challenges of Flexible Duplication Systems, Fast Delivery, and Electronic Service

With the emergence of electronic commerce technology, marketers gained new methods for personalizing electronic advertisements, automating marketing research, and customizing product designs. These developments suggest that production operations also must be redesigned to support contemporary marketing objectives via mass customization. Yet, operations management research historically has focused on mass production systems buffering the customer from production operations. As such, the literature provides relatively few insights about managing mass customization operations. Thus, in this paper, we consider a previously unexamined type of mass customization production operations. The paper presents a case study of a manufacturer's videotape duplication and conversion system, consisting of a flexible network of heterogeneous, parallel machines used to duplicate and convert videotapes and other multimedia. We describe the characteristics of this flexible duplication system, discuss parallels between these systems and mass customization, and identify issues regarding flexibility, speed of delivery, and electronic service.