基于VRML的交互式虚拟装配仿真应用

针对目前CAD软件只生成静态的三维装配体VRML文件的问题,分析了交互式虚拟装配VRML文件的事件流程。虚拟装配中的动态交互性行为使用VRML2.0结合JavaScript进行编程,将机械零部件的动态装配过程以基于VRML的虚拟现实技术来表现出来。     

基于VRML-Java3D的交互式装配可视化环境构建

为了实现基于网络的可视化虚拟装配环境,笔者研究了Java3D与VRML相结合的方法。通过Loader接口将VRML造型文件导入到Java3D场景图中,借助Java语言的事件处理模型,并结合Java3D中的Interpolator内插器对象和Alpha对象,实现交互式添加、拆卸、移动和旋转等装配过程。最后以电机中的转子装配为例,给出了一个基于VRML-Java3D的交互式装配可视化环境。     

数控模具教学中WEB虚拟仿真技术的使用

主要论述WEB虚拟仿真技术在数控模具教学上的意义，以及如何高效快速地获得虚拟仿真VRML．文件，重点介绍如何在数控模具教学中实现静态的WEB虚拟仿真技术和动态交互式的WEB虚拟仿真技术。     

基于VRML和Java的交互式虚拟装配技术研究

虚拟装配是虚拟制造领域研究的热点.阐述了机械零部件虚拟建模流程,研究了虚拟场景与外界交互的手段和方法,通过VRML编程接口 JSAI和EAI与Java的结合,实现了机械部件的交互式虚拟装配仿真,并从产品的拆卸和装配角度出发,以柴油机多缸喷油泵为模型给出了开发过程实例.     

基于VRML的机械产品虚拟装配技术研究

简要介绍了VRML语言定义、特点,阐述了机械零部件虚拟建模方法。对虚拟装配流程进行分析,并对产品装/拆运动的表示形式、虚拟装配路径规划及逻辑控制、虚拟装配过程中的碰撞检测方法等关键技术进行了研究,提出了产品装/拆运动12元组表示形式。最后,通过对机械产品交互式虚拟装配进行实例仿真,验证了该技术的可行性和合理性。     

基于VRML的产品虚拟装配建模的研究

在虚拟装配的过程中建模是基础和前提,虚拟装配建模包括环境建模和零件建模,它对于产品的真实装配有着十分重要的意义。本文根据VRML的特点,重点分析基于VRML的虚拟装配建模的原理和方法。     

基于VRML的虚拟装配技术研究

在最短时间内,开发出质优、价廉的产品是对现代企业生存和发展的必然要求。虚拟装配技术的运用缩短了产品开发周期,提高了企业经济效益。在系统阐述虚拟装配的有关概念、VRML语言、装配仿真等问题的基础上,以单级减速器为例对运行在个人PC上的基于VRML的网络虚拟装配平台结构、实现方法等进行了研究。     

基于VRML和Java Applet的虚拟装配平台的实现

虚拟现实建模语言(VRML)通过外部编程接口VRML-EAI可以和Java Appl et通信,利用这种技术可以实现网络虚拟装配.论述了利用这种技术开发虚拟装配平台的方法,并给出一实例.     

基于VRML的数控机床的虚拟操作研究

虚拟环境下加工设备虚拟操作和虚拟加工是虚拟制造的一个重要研究内容。本文通过对数控机床的虚拟操作的研究,阐述了在VRML的虚拟现实应用平台上建立数控机床的虚拟操作系统的方法,提出了利用VRMLJavaAppletJavaScriptHtml多方相互通信的办法对VRML人机交互功能进行增强与扩展,从而满足数控机床虚拟操作的功能要求。实验结果表明,这种增强办法不仅使VRML原有的人机交互能力得到进一步的增强,并且为VRML添加了接收与处理文本信息以及读写文件等交互能力。此外,文中还提出了一种利用SolidWork与PolyTrans相互结合而实现的在虚拟环境下的数控机床的快速建模方法,并取得令人满意的效果。本系统不但可应用于异地制造、数控机床加工仿真,还可应用于基于WEB的数控机床操作、编程与加工培训等方面。     

面向用户的虚拟设计环境的研究

提出用特征语言对产品族结构进行建模的原理和方法,并结合相应的产品族结构模型进行了分析。在此基础上设计了产品配置器,构造了面向用户的虚拟设计环境的整体框架,并阐述了各组成部分的功能和实现方法。以仪器柜产品的设计和制造为实例实现了系统原型。     

基于Web协同虚拟装配规划的实现

协同虚拟装配是借助于网络对产品进行数字化预装配 ,它是敏捷化设计与制造的基础。本文探讨了虚拟装配的协同机制 ,分析了产品设计过程中相关成员的需求并给出了客户端配置 ,探讨了系统开发工具的特性 ,建立了应用 VRML格式作为数据载体、基于 Web的虚拟装配框架体系。虚拟装配设计模块包括装配路径规划和干涉检查 ,文中分别给出了相应的算法     

A systematic approach for 3D VRML model-based assembly in Web-based product design

Collaborative virtual assembly design is often considered complicated and hardly achievable, for it requires high real-time performance, platform independence, and model synchronization. In order to satisfy all these requirements, a VRML-based virtual assembly solution is proposed. This paper first presents a synchronous moving-searching algorithm for retrieving information from the basic assembly model (BAM) and target assembly model (TAM) in order to give Internet-based collaborative assembly capabilities to these VRML files. Then, a set of assembly approaches for VRML models are systematically addressed to implement the assembly according to constraints of link relations. The advantages of the algorithm and assembly approaches are their high computational efficiency and ease of implementation, which enriches works of Anton and Gorazd (2003) and Qin et al. (2004) with respect to accessibility and maneuverability of VRML model-based assembly design. Moreover, the realization method of collaborative assembly over the Internet is introduced. Finally, some actual examples of collaborative virtual assemblies systems are provided to illustrate the application of these approaches.     

Constrained behavior manipulation for interactive assembly in a virtual environment

Interactive assembly based on virtual reality offers users an opportunity to interact with a virtual prototyping rather than a physical one and to validate assembly performance of products in a realistic way. Such evaluations could be available very early in the product development process ahead of any physical prototyping. The reduction or elimination of physical prototyping needed for assembly performance validation can substantially shorten the product development cycle and reduce development cost. Although virtual reality technology provides users an intuitive and immersive 3D interactive interface, it tends to be inaccurate because humans have difficulty in performing precise positioning tasks. Therefore, it is necessary to implement effective motion manipulation for assembly operations so that users can perform precise positioning efficiently in virtual assembly systems. This paper presents a constrained behavior management approach that realizes assembly relationship recognition, constraint solution and constrained motion for interactive assembly in a virtual environment. A constrained behavior manager (CBM) has been developed and applied in virtual assembly systems. Test cases confirm that constrained behavior manipulation proposed in this paper not only increases the efficiency of assembly relationship recognition, but also facilitates assembly interaction in a virtual environment.     

基于Web的远程虚拟实验环境的研究

对远程虚拟实验室的体系结构和功能进行了论述,给出了外部编程接口EAI实现交互的方法,该方法使外部程序能够通过VRML事件模型访问场景节点,从而交互地控制VRML场景。为了加快碰撞检测,选择层次包围盒方法进行相交测试,该方法采用包围树的结构,检测过程变成了对一棵二叉任务树进行搜索的过程,大大简化了包围体的相交测试。     

基于创建机械零件虚拟模型库的研究

本文以虚拟技术为支撑，以图学教育的宗旨为核心，利用UG软件的三维虚拟模型的造型技术、虚拟装配技术和制作爆炸图技术论述了创建机械零件虚拟模型库的思路和方法，并运用数据库技术，使模型文件结构清晰、管理便利。     

Conceptual design system in a Web-based virtual interactive environment for product development

In this research, a Web-based conceptual design prototype system applied with open-source software (e.g., Java, PHP, etc.) is presented. Aside from the online conceptual design kernel interpreter module, it consists of four parts; a module to extract 3D component hierarchical configurations; a module to plan and view the assembly paths for 3D components; a module to set up the motion paths of components; and, finally, a module to handle the viewing direction of any component or assembly to show the 2D projected drawings in real time. In the first online module, it combines the chosen primitive features with Boolean operators. This module is programmed with the Java 3D module in order to build the CAD components on the platform of interactive design. Then, it infers the 3D configuration by analyzing the 3D modeling history. The configuration is described by a parent–child hierarchical relationship and the relative positions between two features. The positioning information is computed with respect to the VRML specification. The operation and control of the VRML objects is by the behavior modules of a Java applet, which plans the exploded/unexploded paths of the 3-D parts assembly and is specified interactively on the different components. Meanwhile, assigning the viewing direction to show the dynamic assembling process and generating projected drawings is automatically carried out by following the viewpoint assigned by the user. Finally, the system creates the motion file, in VRML format, for the assembly paths and behavioral simulation. This research offers a new virtual environment for collaborating design issues and discussion.