基于图论的产品自动定位设计

为了解决零件加工的手工定位问题，提出基于图论的自动定位设计方法.对零件特征按加工过程中几何拓扑结构以及功能进行分类和定义.将设计公差分成全局公差和局部公差，通过引入相对公差因子概念，将全局公差转化为相对公差因子，作为特征间约束的权值.采用图论方法将计算机辅助设计零件模型表示为特征 公差结构图，研究了特征-公差有向网络图构造方法，给出了特征-公差结构图有向化规则.在特征-公差有向网络图基础上，研究了零件加工自动定位设计的基本规则.实例验证表明，该方法能实现零件加工的自动定位设计.

Product automated setup planning based on graph theory

To solve the problem of setup planning by manual,a new method based on graph theory was developed.The part features were classified and defined according to the geometric topology and functions in part machining.The design tolerances of the part were classified into global tolerance and local tolerance.By introducing the concept of relative tolerance factor,the global tolerances were transferred into relative tolerance factors as the constraint weights between features.Computer aided design(CAD) model was represented as a feature-tolerance graph according to the graph theory,and the directed rules were studied to transfer the feature-tolerance graph into a directed feature-tolerance network,then the rules of setup planning were presented in terms of the directed feature-tolerance network. The results demonstrate that the proposed method has feasibility and effectiveness in automated setup planning.