Feature-based modeling of automobile gears and manufacturing resources for virtual manufacturing

The manufacturability evaluation is an important component of virtual manufacturing and concurrent engineering, and hot spot of this research is focused on manufacturability evaluation based on feature at present. In this paper, using the object-oriented modeling methodology, according to the manufacturing features of the gears used in automobile, the gears are classified into cylindrical gears and bevel gears to carry on the feature modeling separately; the manufacturing resources are classified into the basic information of the manufacturing equipments and the feature processing capability information to establish information models, and the association relationship of features, machine tools, and process equipment is established simultaneously. All of the models established in the article provide the information support for manufacturability evaluation and lay a good foundation for virtual manufacturing.     

面向制造网格的应用平台及虚拟企业建模研究

在分析制造网格、计算网格和网络化制造之间差异的基础上,探讨了面向制造网格的应用平台及虚拟企业 建模等问题。首先,分析了制造网格和网络化制造在资源组织和应用模式上存在的差异,提出一种面向制造网格 的应用框架;其次,研究了制造网格相对于计算网格所具有的多变业务目标、多级资源共享、资源服务的提供和 结果提交的在线和离线混合方式的特点,形成了制造网格的应用内涵;然后,在剖析计算网格、基于资源服务的 制造网格以及应用程序等基础上,形成了从业务链、资源服务链到网格节点链的处理过程,并最终导出了面向制 造网格应用的虚拟企业的组织模型。最后,通过对问题的量化描述了应用平台的处理过程和算法。上述研究对于 推动制造网格的应用和虚拟企业的组织建模具有积极的意义。     

A multi-stage methodology for virtual cell formation oriented agile manufacturing

In recent years, as an emerging concept in industry, agile manufacturing has attracted considerable attention, combining virtual manufacturing cells to construct new manufacturing systems to respond to the changing market needs, especially in nonlinear processes. In this paper, a multi-stage cell formation methodology, which can help select appropriate resources and form the VCs, is presented. First, appropriate resources for completing production tasks are selected by a LP model considering the available capacity and the costs. In order to form VC in a logical mode, parts having alternative product process routings as multi-functional machines are analyzed by a resource element approach. Furthermore, some routing-based heuristic rules are introduced to optimize the candidate VCs in the form of resource elements. Finally a case study is used to illustrate the detailed formation methodology.     

基于PDM的数字化产品虚拟制造系统研究

分析了PDM(Product Data Management,PDM)技术与虚拟制造技术(Virtual Manufacture,VM)的特点及重要性,将产品数据管理技术与虚拟制造技术有机地集成,为新产品开发提供一套更加有效的工具.随着科学技术的发展,数字化产品设计成了产品设计的主流.基于数字化设计制造的思想,将所有产品数据与虚拟制造技术相结合,搭建了PDMVMS(Virtual Manuflacture Svstem based on Product Data Management,PDMVMS)平台,研究了其主要的建模技术与关键问题.     

Computer-aided lofting,fairing and manufacturing in small shipyards

A computer-aided surface lofting, fairing and manufacturing program, called G-SURF, has been developed for, and successfully implemented in, a small shipyard. The interactive menu-driven package runs on an IBM-AT or equivalent personal computer and interfaces with standard three-dimensional wire frame drafting packages. The naval architect's small scale design drawing is approximated by a minimum number of smooth three-dimensional skeletal-lines running along the entire length of the surface. The skeletal-lines are formed by parametric taut-cubic polynomial splines and represent the essential features of the hull form. These lines are normally the profile, shear, chine and intermediate lines as necessary and are individually adjusted in three-dimensional space until smooth. A set of station-lines is formed as required through the skeletal-lines to fully define the hull surface. The hull can, if required, be lofted and faired as a developable surface that can be formed from flat sheet plate. The algorithms embodied in the program ensure developability and produce flat plate definition of the unwrapped hull form. The individual component plate shapes can be displayed on a graphics screen and interactively arranged to fit on a standard size of sheet plate material. During this ‘nesting’ process, the spacing between components, location of bridges, and direction, path and speed of cut are all specified. Positional nested plate data are postprocessed to give G-code data for a plasma-arc plate burning machine. G-code machine instructions can be sent directly from the host computer via an RS-232C serial line to the machine tool or can be stored on a disk for later use. The storage and transmission of part programs avoids the medium of punched paper tape, is flexible, reliable and can handle large amounts of data. Implementation of the G-SURF package has reduced the lofting, fairing and manufacturing time for ship hulls by a factor of three.     

虚拟计算机集成制造系统(V-CMIS)的研究

介绍虚拟计算机集成制造系统的主要组成部分，阐述智能管理子系统、虚拟设计子系统和虚拟制造子系统的体系结构、构成框架和相互关系，以及基于C-S和B-S模式的分布式数据处理模式及网络构建方式。     

基于驾驭式虚拟加工的平面二次包络蜗杆实体造型

介绍了在VBA环境下，运用虚拟加工技术开发机械零件三维实体造型的实现机制和关键技术，通过引入驾驭式控制方式实现了对仿真过程的实时控制，并通过平面二次包络环面蜗轮副实体造型程序实例，阐述了三维驾驭式实体造型的设计方法。为该型蜗轮的数控加工提供合适的数学模型及相应的CAD数据接口，达到蜗轮数字化造型的目的。     

Design of flexible manufacturing systems on the basis of CAx software and virtual modeling

Structural synthesis of flexible manufacturing systems for the machining of batches of parts and subassemblies at the preliminary design (technical proposal) stage is considered, on the basis of CAx software and virtual modeling of the control system. This is the key stage of design, since the structural synthesis of the flexible manufacturing system largely determines the economic viability of the design as a whole.     

复杂曲面的UG建模、加工与Vericut虚拟仿真

本文利用UG的CAD建模和CAM加工模块,分别介绍了复杂曲面的建模和实现自动编程的全过程,最后,在Vericut环境下进行了的虚拟仿真.UG和Vericut的有效结合,能减少零件的试制周期,节约经费,并能提高零件的加工精度.     

面向虚拟维修的拆卸过程建模研究

本文对维修拆卸和回收拆卸的进行特点对比,根据维修拆卸自身的特点,提出了维修拆卸过程信息图(Maintenance Disassembly Process Information Graph,MDPIG)的概念,构建了一种适合计算和优化的维修过程信息图模型,该模型描述了零部件之间的连接关系和优先关系,为应用智能优化方法进行维修拆卸序列规划提供了一个相当适合的模型.     

基于MDU元建模方法的弧面分度凸轮虚拟设计研究

对弧面分度凸轮的虚拟设计模型的建立需要考虑模型数据的可重用性,模型间数据的一致性与互操作性。基于MDU的元建模方法建立的弧面分度凸轮模型可以实现模型间的信息交互与无缝集成,这里初步建立了弧面分度凸轮机构的元模型,对进一步的弧面分度凸轮的参数约束与拓扑约束的参数化设计有着积极的作用。     

面向网络制造的虚拟组合夹具站的研究

在组合夹具装配过程中由于存在元件图库、元件库存、夹具图库的信息关系不明确、数据连接策略模糊等一系列问题,使设计出的组合夹具不能立即投入使用,限制了组合夹具的应用.针对这一情况,提出建立一个虚拟组合夹具站.利用网络优势,将组合夹具的制造者、使用者和设计者联系起来.不仅实现了组合夹具元件库存及夹具图样等信息的科学管理,同时提高夹具的设计效率,缩短产品生产周期.     

面向订单制造的可重构制造系统中虚拟制造单元构建技术

为适应单件、小批、个性化和市场需求动态多变的特点.研究了多种不同交货期生产订单并存时的可重构制造系统中虚拟制造单元构建问题.构造了以连续加工产品间相似系数之和最大、工作加班时间最少、单元的封闭性最好(工件跨单元搬运次数最少)、制造系统重构成本最小及设备生产负荷均衡为目标的非线性多目标0-1整数规划模型.采用两阶段的求解策略进行求解.在第一阶段采用启发式方法对非瓶颈设备和工艺进行预处理,以缩小问题解的搜索空间;第二阶段采用一种基于网格计算的分布式平行协同多目标粒子群算法,随机搜索Pareto优化解集.最后,利用globus 4.0 工具箱搭建计算网格和Java语言实现了算法.从生产实际出发给出了算例,证明结果可行,从而验证了算法的有效性.     

虚拟加工建模的研究

文章针对虚拟制造的关键技术之一－－虚拟加工进行了深入的研究。针对铣削加工过程,提出了一种过程仿真模型。该模型通过在几何仿真中实时计算瞬时切削厚度来计算刀具振动,从而将几何仿真与物理仿真有机地结合起来。仿真与实验结果证明了该模型的合理性。该方法的进一步研究对于建立加工过程物理几何动态仿真模型具有重要的意义。     

整体叶轮产品造型和数控加工研究

基于大型CAD/CAM软件系统,完成复杂产品整体叶轮产品造型和五坐标数控加工编程,为复杂产品的模型建立和多坐标数控编程提供了设计思路和方法。     

虚拟制造技术在制造业中的展望

在分析中国制造业面临的机遇和挑战及虚拟制造技术的内涵基础上,简要说明虚拟制造的应用状况,提出今后的发展方向.     

协同产品商务制造系统的性能分析模型

在阐述协同产品商务概念、企业信息化发展趋势和制造系统类型的基础上 ,探讨协同产品商务制造系统的性能特征 ,建立基于目标 (G)、性能 (F)、模式 (T)、视图 (V)和过程 (P)五元集合的协同产品商务制造系统总体模型 ,进而建立过程 /性能 /视图 (PFV)、过程 /模式 /视图 (PTV)、过程 /模式 /目标 (PTG)和过程 /性能 /目标 (PFG)三维性能分析模型     

虚拟制造技术(VMT)的发展与应用研究

对虚拟制造技术的发展与应用进行论述,重点介绍虚拟制造产生的背景和涵义,虚拟制造与实际制造的关系,实施虚拟制造的收益,虚拟制造的关键技术及目前的研究与应用现状等,并对虚拟制造的应用前景及发展方向进行展望.     

Study on manufacturing grid resource service QoS modeling and evaluation

Current research on manufacturing grid (MGrid) systems has mainly concentrated on its concept, architecture, application prototype platform, and application foreground. Absent from the trend is the quality of service (QoS) of MGrid, such as QoS modeling, QoS evaluation, and QoS-based scheduling, which play a very important role in MGrid resource management. The related topics about MGrid and QoS are investigated in this study. The characteristics of QoS associated with its management requirements in MGrid are then further studied. Classification and modeling of MGrid QoS are investigated from three different perspectives: QoS whole-lifecycle management, MGrid architecture view, and QoS attribute parameters. The measurement and evaluation models of QoS parameters in MGrid are presented. A simple case study is described to illustrate how the proposed works can be applied to MGrid resource service management.