多面体模型Cutter/Workpiece Engagement计算的局部化方法

为减少多面体模型中参与Cutter/Workpiece Engagement计算的面片数量,提出了一个基于R树的局部化方法.该方法用R树记录多面体模型中的面片.针对多面体模型的几何特点采用R树插入算法,以尽量减小节点尺寸与节点之间的重叠程度.由节点与刀具轨迹的几何关系来确定分裂轴与分裂参数,使分裂后的节点沿刀具轨迹呈块状分布,以提高检索效率.面片搜索策略采用基于R树的深度优先搜索算法,通过判断面片与刀具的位置关系,能实时检索出处位于刀具周围的面片.只有这些检索到的面片参与Cutter/Workpiece Engagement计算,大大减少了参与计算的面片数目.

Localization method for polyhedral-model-based Cutter/Workpiece Engagement calculation

To improve the efficiency of polyhedral-model-based Cutter/Workpiece Engagement(CWE) calculation,an R-tree-based localization technique was proposed to reduce the number of facets which were considered in a given CWE calculation.The proposed method recorded the facets in a polyhedral model using an R-tree.According to the geometric features of the polyhedral model,an insertion algorithm for R-tree construction was presented to reduce sizes of the nodes in the R-tree and overlaps among them.The R-tree splitting axis and parameter were defined by geometrical relationship between node and toolpath so that the nodes in the R-tree were located along the toolpath and index efficiency could be improved.Once the R-tree was built,R-tree-based depth-first-search method was adopted to index the facets near the tool at any given position along the toolpath. Only these indexed facets were involved in the CWE calculation,and the efficiency of the calculation was improved.