【作者】 张来生；

【导师】 陈忠良；

【作者基本信息】 中国农业大学 ， 机械设计与理论， 2000， 硕士

【摘要】 本文评述了计算机辅助设计、人工智能和参数化设计的特点和发展趋势，结合国内外二维机械产品辅助设计系统的开发与应用状况，将智能参数化设计成功地应用到计算机辅助设计系统中，研究开发出二维零件图与装配图一体化参数化设计系统——PCAD2000参数化系统。 论文首先分析了二维机械零件的参数化设计方法（包括通用零件、标准零件等），并在原PCAD2.0对参数化系统的基础上，提出了一种基于特征的零件图参数化设计方法，该种方法改变了传统CAD系统完全依靠设计者指出零件几何图素（点或线）的位置这一限制，将零件几何体的多个图素结合在一起，形成了一个以“特征”为操作单位的新的语义实体，这样大大方便了零件的参数化设计和修改，提高了设计的效率和准确性。 然后，论文以零件图的参数化设计为基础，进一步提出了基于约束分析的二维装配图参数化设计方法，该种方法采用树型的层次模型作为本参数化系统的装配模型，并使用改进的Newton-Raphson迭代算法进行位置约束机制的求解，该装配模型能够满足机械产品的自顶向下设计要求。通过本系统提供的装配模型不仅能够实现二维装配图的参数化改型设计，而且初步达到二维零件图与装配图一体化参数化设计的目标。 参数化系统PCAD2000与AutoCAD R14的强大图形处理功能结合到一起，为计算机辅助设计开辟了一条智能参数化设计的新途径，更为智能参数化CAD系统的研究与应用作了有益的尝试。更多还原

【Abstract】 In this paper, characteristics and trend of CAD, Al and parametric design are discussed. Al parametric design is applied to CAD system, which combined the development and application’s status of 2_D mechanical manufacture CAD system. The incorporate design system of 2D part and assembly drawing parametric (PCAD2000 parametric system) is developed. This paper analysis the parametric design method of 2_D mechanical part, including all-purpose and normative part. The part parametric design based on feature is developed from the PCAD2.O system. The feature parametric design tied in multi-graph of geometrical-shell, forming a virgin semantic entity with “feature” operation unit. In this way, the method had no use for pointing out the position of part geometrical graph-unit (point or line). Therefore, the design and modification of parametric part based on feature become very advantageous. At the same time, which improves the efficiency and veracity of design. Then, The 2_D assembly parametric design method is advanced, Which is based on constraint analysis. This method made use of the layer model of binary tree as the assembly model. Which used the improved Newton-Raphson iterative arithmetic to make progress the solution of constraint mechanism. Which meet the top-down’s design demand of mechanical product also. Through the previous model, not only the parametric retrofit design of 2_D assembly drawing is carried out, but also the incorporate design of 2D part and assembly drawing parametric is achieved. The PCADD2000 and powerful graphics process of AutoCAD R14 are combined effectively, intelligent parametric design of CAD is carried out. A new way is opened for parametric CAD in this study, as well as a useful try for study and application of intelligent parametric CAD.更多还原