Doo-Sabin曲面NC刀具的并行轨迹计算

Doo—Sabin曲面是对多边形控制网格进行递归细分的极限曲面．利用Doo—Sabin曲面具有的逐步逼近的多分辨率特性和误差公式,根据加工误差确定控制网格的细分次数,并以此代替目标曲面进行粗加工刀具轨迹计算,从而合理简化了加工细节,提高了粗加工效率．另外,改进了传统的G—Buffer技术,提出了能统一应用于大型工件粗加工和精加工的S—Buffer算法．进一步分析了S—Buffer数据的相关性,采用平均加权响应时间为性能指标,设计了抢先式的动态负载平衡策略,基于MPI实现了S—Buffer的并行化．

A Parallel Method for Generating NC Tool Paths of Doo-Sabin Surfaces

Doo Sabin surfaces are the limits of recursively refined polyhedral meshes The recursion depth n of a Doo Sabin surface is estimated according to the error equation Then the polyhedral mesh after n steps of subdivision is used as a substitute for the limit surface during rough machining to simplify the tool paths The traditional G Buffer method is extended to a strip buffer method (called S Buffer) to generate NC tool paths for objects of large size Furthermore, we analyze the locality of S Buffer, adopt the weighted response time as a performance index, and develop a preemptive and dynamic task assignment and load balance strategy Thus we effectively parallelize S Buffer based on the message passing interface(MPI)