【作者】 周凯旋；

【导师】 罗会信；

【作者基本信息】 武汉科技大学 ， 机械设计及理论， 2006， 硕士

【摘要】 应用CAD技术可以起到提高企业的设计效率、优化设计方案、减轻技术人员的劳动强度、缩短设计周期等作用。虚拟现实技术在CAD中已经开始应用,它提倡沉浸式的设计,可以验证设计的正确性和可行性。近些年来,一些企业在完成了二维CAD技术应用之后,开始转向三维CAD技术,甚至在CAD技术中融合虚拟现实技术,以取得更大的经济效益。为了实现这两种技术的融合和更有效地发挥三维CAD系统的作用,我们可以对三维CAD系统进行二次开发,实现CAD系统的智能化、专业化和用户化。所谓CAD软件的二次开发,是指在通用CAD软件的基础上,为提高和完善软件的功能,使之更符合用户需要而做的开发工作。其根本目的是提高设计、制造质量,缩短产品的生产周期,充分发挥CAD软件的作用。装配设计是起重机设计工作的重要一环,虚拟装配技术作为虚拟现实技术在设计与制造领域的重要应用之一,近年来取得了长足的发展,有些虚拟装配系统已经开始工业应用。本文的研究工作将虚拟现实技术与三维CAD技术相结合,研究桥式起重机的虚拟自动装配及装配中的干涉检查。在此研究中,作者选用先进的三维CAD软件平台-SolidWorks,进行起重机的建模;并运用面向对象的设计语言-Visual Basic,利用SolidWorks的API函数和OLE接口对其进行二次开发,开发出起重机小车的创新虚拟装配设计和干涉检查系统。此设计系统是通过VB编程,在SolidWorks软件平台上外挂系统程序,程序的运行就如同SolidWorks调用自身功能一样,来实现设计功能。本文在进行虚拟自动装配开发时,根据起重机的机构组成特点,采用分层装配的规划设计思路,先由单个零件组装成小部件,再由小部件组装成大部件,最后将各部件组装成整台起重机小车。装配中的关键技术是利用辅助特征构造装配选择集和简化装配零件数量。通过设计用户对话框,装配二次开发实现了起重机小车虚拟自动化装配,在装配过程中可实时修改装配参数、更换装配零部件,以及通过用户对话框方便地修改零件尺寸参数,达到非标设计的目的。干涉检查是起重机虚拟装配中的任务之一,其计算量比较大,算法的效率高低直接关系到系统的运行速度。本文分析了干涉检查理论和几种干涉算法,在二次开发中采用递归的逐层分解的包络盒算法,利用元件沿着装/拆运动轨迹形成的包络体代替元件本身参与求交运算,形成了一种三级递进式的干涉检查算法。开发专用CAD系统将会有力推动工厂推广真正意义上的产品CAD,实现智能化设计。对起重机三维CAD系统开发的探索和研究,会为以后进行的其他产品CAD系统开发做好技术上的准备,其方法、思想和经验均可引申为其他系统所用。更多还原

【Abstract】 The application of CAD technology to manufacturing industry can increase efficiency,optimize blue print,lessen designer’s oppressiveness and shorten project’s period.These years,in order to gain more economical benefit,some corporations are going to adopt three-dimensional CAD software after application of two-dimensional CAD technology. It’s proved that to make CAD software works more efectively,secondary development of them is necessary.The secondary development of CAD is to improve and perfect the software’s function based on general CAD software.The basic purpose is improving design and manufacture’s quality,and shorten production cycle.Assemble design is very important as a part of bridge crane design.As a visual reality technology applied in design and manufactual field,visual assemble technology has been gained quiet great development.Some visual assemble system has been applied in industry.The research in this paper is combining VR and CAD technology,to develop a special design system for bridge crane.In the study,we choose a advanced 3-D CAD software-SolidWorks to modeling the crane,and use an object oriented computer language-Visual Basic for secondary development of SolidWorks by its API function and OLE interface.In this paper,it will introduce the crane’s automatic assembly and collision detection function of design system.The system program is written in Visual Basic and hanged to SolidWorks flat roof.So,it seems SolidWorks runs its own function when we run the program.In detailed work of visual assemble design,according to organization of crane’dolly,author applys bed assembly technology by secondary development of Soli- Works,that means small assemblys assembled first then big organs and the whole dolly last.We can modify the assemble or parts’parameter and replace parts in time by designing user dialog box.Meanwhile,the paper contains development of assemble collision detection.Algorithmic efficiency has a close connection with running speed.The development of special CAD system will be useful for factories popularizing product-CAD and intelligentive design in deed.Exploring and study on secondary development of crane’s 3-D system will provide technology support for other products’CAD system development in the future.Its method,ideology and experience all can be used in other systems.更多还原