中文摘要：

针对尺寸链自动生成所存在的问题，提出一种基于装配约束的尺寸链自动生成方法。依据零件间的装配定位约束的不同，建立SDT模型的表示模型和作用模型，改进装配有向图，在有向图中添加了基准约束信息。基于改进有向图，建立主尺寸链以及辅助尺寸链的装配约束关联矩阵，通过最短路径以及对关键特征的自动搜索，实现了尺寸链的自动生成。

英文摘要：

In view of the existing problems in the automatic generation of dimension chain, put forward a kind of automatic generation of dimension chain method based on assembly constraints. Based on different assembling positioning＇ constraints between parts, establish SDT model representation model and role model, improved assembly digraph, in addition there is a reference to the constraint information in FIG. Improved directed graph, the establishment of assembly constraints associated matrix column size and the auxiliary chain size even by the shortest route and the key features of automatic search, to achieve the automatic generation of dimension chain.