【作者】 唐秋华；

【导师】 陈定方； 孔建益；

【作者基本信息】 武汉理工大学 ， 机械设计及理论， 2005， 博士

【摘要】 虚拟环境(VE,Virtual Environment),又称为灵境,是以计算机技术为核心、利用现代高科技技术生成的集视觉、听觉、触觉于一体的,具有空间和时间特性的数字化多维信息空间,是虚拟现实(VR,Virtual Reality)技术的具体体现。虚拟环境,可以是当前并不存在的环境,是对人们实际工作的计算机预演;可以是人们由于时间、空间和体力、能力所限不能到达的环境,便于人们对客观事物生动、直观、形象、具体地进行研究;还能替代耗资巨大的现实环境,节约时间或空间,降低成本。总之,在虚拟环境中,人们可以自然地和虚拟环境中的客体进行交互,相互影响,从而产生亲临现场的感受和体验。故虚拟现实基于现实,又可超越现实、智能现实、预测将来。 本文侧重于分布式虚拟环境建模的研究,系统性研究了面向分布式虚拟支撑环境的物理建模机制、通讯机制、时间同步机制等方面的关键技术、理论和方法,实现了建模工具、资源的互操作能力和可重用性,体现出了分布、交互、并发、协同的性能,并在此基础上,针对特定应用建立虚拟环境分析模型,开发了应用系统,在公司和企业进行了实际应用。主要成果和创新点有: (1)本文研究了将三维CAD模型转换为虚拟环境中兼具几何准确性、形象真实性的静态模型和可操作动态模型的策略和理论,并用渐开线圆柱齿轮的虚拟设计实例加以说明和验证。对于CAD/CAPP/CAM走向虚拟现实研究方法,大量存在的三维模型向虚拟环境的转换是必然的一步,本文中将CAD模型转换成虚拟环境模型的工作具有显明的实用价值。 (2)本文在基于图像和基于几何的虚拟环境建模方法基础上,以室内设计为对象,解决了根据已有实物图片拟实以虚、构造可虚拟浏览的二维实物全景和根据未知实物建模拟虚以实、生成可漫游的三维虚拟环境两种室内虚拟环境生成技术。 (3)基于虚拟环境的需求,本文研究了虚拟环境中所需的分布式处理技术,包含分布式虚拟环境的网络体系和通讯协议,并着重说明了数据传输机制和智能化虚拟环境所需Agent的结构,最后基于VRML和Java实现了一个分布式虚拟装饰实例。更多还原

【Abstract】 Virtual Environment (VE), vivid and realistic environment in computers, usually refers to the multiple dimensions information space, in which computers are used as the core equipments and modern high-tech techniques are applied so that many senses such as vision, hearing and touching are integrated together and characteristics of Time and Space are possessed and Virtual Reality technology is embodied concretely. Virtual environment, which can be the nonexistent environment at present, can preview the future works to the people in advance; which can also be the ultra-limit environment that the people can not arrive because of limit of time, space and physical strength, ability, can control and display those objective things vividly, directly, figuratively and racily; which can take place of the expensive realistic environment, economize the time and space and decline the cost. In brief, in virtual environment, the people can interact mutually with an object in virtual environment naturally and affect each other conveniently, thus the feeling and the experience of real world can be obtained through virtual environment. Virtual environment base on the real world, surmount it, and then intelligentize it and predict the future scientifically.The Modeling of the Distributed Cooperative Virtual Environment is emphasized particularly on in this dissertation. The key techniques, theories and methods about the modeling mechanism, communication mechanism and time synchronization mechanism oriented to distributed cooperative work in virtual environment are studied systematically at first. Therefore, mutual operation and reuse of tools and resources is realized, and the function of distribution, interaction, parallel and cooperation is embodied. Furthermore, special virtual environment analysis models for particular application are made and the application systems are developed at last and carried on in specific ompany andenterprise. The major results and innovations are as follows:(1)The strategies and theories about converting the traditional three dimensional CAD models to static and dynamic models, which possess geometry accuracy and figure reliability at the same time, are proposed and explained in details and then verified by the example: virtual design of Involute- Column-Gear. The step for converting a great deal of existent models to virtual environment models is so inevitable in future according to the research methods from CAD/CAPP/CAM to virtual reality that its practical value is obvious.(2) Two kinds of interior virtual environment modeling techniques is proposed, based on image and geometry virtual environment modeling. That is, while interior design is taken as the object, two dimensions real object panoramas in which browse is supported according to real object picture and three dimension virtual environment according to the virtual object modeling in which virtual traveling function is constructed.(3) Distributed processing techniques specially used for virtual environment is studied, including network structure and communication protocol of DVE, and transfer mechanism and the structure of Agent for intelligent virtual environment is emphasized and an example of distributed virtual decorating design based on VRML and JAVA is carried out.(4) The method for realizing virtual product design system under the customer Web-VR environment is proposed based on the former chapters and three dimension product geometry models is reconstructed and product feature information are represented in suitable format and communication and association mechanism between customers -designers are realized together.(5) The original content of virtual assembly is enlarged. Based on the original structure of virtual assembly system, the layer structure of virtual assembly is considered and then layer tree assembly modelsbased on disassembly is constructed and strategies of automatic assembly sequences layout is developed and then an example of virtual assembly of Double Grade Involute Column Gear Retarder based on WTK is cited and discussed for demonstrating the process of virtual assembly.(6) Some basic quests and researches are done in the realm of multiple robots cooperative virtual assembly operation. Based on the layer structure of structure of virtual environment, layer driven robot operation is proposed to realize multiple robots operation control in virtual environment and then cooperative operate strategy based on layer-mixed structure is researched in details and information synchronization controlling based on Petri-net and mixed communication models is researched and multiple robots cooperation virtual modeling modules is built up.The theory of distributed cooperative virtual environment modeling is expansive and intensive in this dissertation. As a new type research method and technology measure, its application and expansion in each profession can be expected soon, therefore this dissertation also have the important theory meaning and practical values.更多还原