基于图论的装配尺寸链自动生成技术

Automatic generation technology of assembly dimension chain based on graph theory

针对装配尺寸链自动生成难题,提出一种基于特征有向图表达的装配尺寸链自动生成方法,该方法首先建立四层结构的装配精度信息模型,并对公差信息的进行规范化处理和约束信息转化,在此基础上获得几何公差特征矩阵和装配特征关联矩阵,然后采用图论建立装配体有向图模型并剔除与装配精度无关的有向图的顶点和边,最后利用最小路径原理实现了装配尺寸链的自动生成。借助ACIS和HOOPS工具,开发了原型系统并进行了实例验证,证明了该算法有效缩小了装配尺寸链的搜索范围,同时保证了装配尺寸链自动生成的准确性。

Aiming at the automatic generation problem of assembly dimension chain, a new method based on featurc-expression of directed graph was proposed. Anassembly precision information model with fou〉layer structure wasconstructed to standardize the tolerance information and transform the constraint information. On this basis, the ge-ometric tolerances characteristic matrix and assembly features correlation matrix were obtained. By using the graphtheory, a directed graph assembly model was established which rejected the irrelevant vertices and edges of directedgraph, and the automatic generation of assembly dimension chain was realized with the minimum path theory. Aprototype system was developed by using ACIS and HOOPs geometric modeling tool to verify the proposed method.The result showed that the search range of assembly dimension chain was reduced by this method effectively, andthe accuracy of automatic generation of assembly dimension was ensured.