【作者】 张为涵；

【导师】 林亨；

【作者基本信息】 清华大学 ， 材料加工工程， 2003， 硕士

【摘要】 随着社会的发展和人们需求的不断提高，顾客不仅追求商品的功能和成本，而且对其开发的周期和个性化提出了更高的要求。虚拟设计技术利用数字化模型进行产品开发，能较好地满足这一要求。本文介绍了一种协同式产品外形虚拟设计平台，它利用虚拟现实技术建立自然的设计界面，利用力反馈位置输入装置产生一系列虚拟雕刻操作进行设计，利用WinSocket编程建立网络连接，实现网络协同设计，通过和数控机床建立无缝连接还可快速加工出所设计的产品外形。文中提出了在微机上实现协同式虚拟设计的思想，在文献调研的基础上，通过分析比较，在多个方案中选择了利用OpenGL和VC++进行系统软件开发的方案，给出了协同式虚拟设计系统的基本框架，分析了研究的主要问题。为了解决系统实时性问题，运用光线跟踪算法以及一系列加速算法，把复杂的三维图形运算转化成一系列简单的一维图形运算，使每次设计交互的循环周期降低到20ms以内。针对真实感图形界面的要求，利用OpenGL强大的绘图功能，进行三角形的绘制、纹理的贴图、光照的模拟，并采用时分制法和分光法实现了立体显示，使系统逼真可信。通过在VC++环境下调用Socket中间件-NDK2．0搭建服务器／客户端模式的网络结构，实现了多机异地协同设计。针对人机交互的问题，研制了一套三自由度位置输入和力反馈装置。在硬件实现上，采用三关节机械臂结构，通过安装在每个关节上的光电编码器检测每个关节的转角，进而计算出位置信息。通过微型直流减速电机实现力反馈。在软件实现上，开发了一套位置计算和力反馈算法程序。最后，进行了一系列产品外形的协同式虚拟设计和快速试制实验。结果表明，设计系统在实时性、逼真性和易用性三方面达到了系统的设计要求，并能与数控机床进行连接，实现快速试制。更多还原

【Abstract】 With the rapid development of economy and the improvement of people’s living standard, customers are not only satisfied with product’s good quality and various of functions but also the short developing period and special characters. Virtual design technology is used to meet this need by using digital models to develop products.In this paper, a collaborative virtual product design platform is introduced. Virtual reality technology is used to build the human computer interface, haptic feedback input device is used for producing a series of sculpting operations to change the shape of the model, collaborative design environment is realized by programming WinSocket programs, rapid manufacturing is implemented by connecting with numerically controlled milling machine.The method of collaborative virtual design on personal computer is put forward in this paper. Based on the former experiences, OpenGL and Visual C++ are selected to be the developing tools for this platform, at the same time, the basic frame is outlined and problems are analyzed.In order to reduce the time of one updating period to 20 millisecond, ray-tracing algorithm and other speeding methods are used to convert three dimensional calculation into one dimensional operation. OpenGL functions are performed to draw triangles, paste pictures on models, and simulate the real light rays to get realistic stereo graphic interface in virtual environment. Windows Socket middle ware-NDK 2.0 is used to build the network structure.A three dimensional haptic input device is built to let the designer interact with computer. It has a photoelectrical coding device on each mechanical joint arm to detect the rotating angle, then the device’s coordination can be calculated with the value of the angle. The function of haptic feedback is realized by using micro DC motor and corresponding algorithms.At the end of the paper, some experiments are taken to demonstrate that the design system has already reached the aim of short riming time, realistic virtual environment and easily used interface. What’ more, rapid manufacturing is implemented by connecting with numerically controlled milling machine.更多还原