曲面展开CAD系统设计与研究

【作者】 蒋德军；

【导师】 宗子安； 陈铁坚；

【作者基本信息】 湖南大学 ， 机械工程， 2003， 硕士

【摘要】 本文阐述了建立曲面展开计算机辅助绘图系统在现代生产中的作用与必要性。结合工程实际对曲面构件进行了分类，并通过分析建立了包括圆柱、圆锥、圆柱与圆柱相贯、圆锥与平面相贯等曲面构件的数学模型，确定了适当的展开方法，以AutoCAD2000为平台，以AutoLISP结合ActiveX对象为工具，进行二次开发，设计了曲面展开CAD系统，从而实现钣金件展开图的参数化绘图。该系统包括菜单、参数化绘图程序和DCL对话框设计，其中菜单采用图标菜单，并能和AutoCAD标准菜单进行切换；对话框主要采用图象控件、EDIT-Box编辑框和Radio button按钮；参数化绘图程序采用AutoLISP语言编制，每一种曲面构件展开单独编制一段程序。每一段绘图程序都由三个模块构成，第一模块为对话框管理和驱动程序并对对话框输入的参数进行回调；第二模块为计算程序，利用上面回调所得到的参数，再根据上面得出的计算公式，计算展开图上各点坐标；第三模块为绘图模块。 通过实践验证，本系统具有以下优点：展开图形参数化，图形生成速度快，展开图精度高；而且可以对随着钣金构件尺寸变化时的展开图图形进行分析。使用面广，可用于数控切割机，也可用于产品图纸设计中绘制放样图，标注尺寸，直接指导生产。更多还原

【Abstract】 This paper deals with the role and the prerequisite of establishing the computer-aided drawing system by means of unfolding sheet metal in modern production. The sheet metal work pieces are first divided into several groups such as cylinder, cone and so on. Then, under considering the intersection of two cylinders or a cone and a plane, the mathematical models have been developed, and the corresponding unfolding methods have been determined. On the platform of AutoCAD, the system has been redeveloped by means of AutoLISP and ActiveX object, and the unfolding CAD system has been designed, which can realize the parametric drawing of the extension of sheet metal. The system includes the menu, the programs of parametric drawing and the DCL dialog box. The menu is designed by icons, which can be switched to the menu of AutoCAD. The dialog box include image and Edit-box and Radio-button. The program of parametric drawing is designed with AutoLISP. Each surface has its own program. Each program consists of the following three modules: The first one is the program of managing and driving the dialog box, which can adjust the input parameters of the dialog box; The second one is the calculating program, which can calculate the coordinates of the points in the unfolding drawing. The parameters used in the second module are obtained from the first module. The third module is drawing module.The system developed in this paper has the following advantages: parametric drawing, high drawing speed, high accuracy of unfolding drawing, Analyze the unfolding drawing of sheet metal when dimension has been changed, wide application. So it can be used in CNC cutting machine and guide the production directly.更多还原