【摘要】 基于STEP-NC应用数据模型和标准数据存储界面(SDAI),通过构造数据字典模型、实体实例数据结构模型和零件实例数据结构模型,建立了描述STEP-NC加工程序的零件-实体分级数据结构,实现了STEP-NC数据到C++数据的转换.采用步进式构造方式提取STEP-NC程序信息,通过回溯递归方法构造了STEP-NC单元实体实例,进而匹配实体属性项内容,建立了零件级的数据结构.该方法避免了SDAI迟联编在实体建立和实体实例建立之间的时序矛盾.最后开发了信息提取原型系统,实例论证表明,该系统能够识别STEP-NC数控加工程序,并显示零件单特征几何形体.更多还原

【Abstract】 Based on standard for the exchange of product model data-numerical controllers(STEP-NC) and standard data access interface(SDAI),a two-level partentity data structure was constructed to transform STEP-NC data to C++ data.And data dictionary model,entity instance data structure model and part instance data structure model were also described.In the course of information extracting,data were constructed in a step-by-step manner.The cell entity instance was constructed by backtrack recursive procedure,then the entity attribute content was matched,finally the part-level data structure was constructed.This process avoids the conflict between entity constructing and entity instance constructing in SDAI later binding.In such way, a STEP-NC information extracting prototype system was developed.By inputting ISO14649 example data,the information were extracted and the part was also displayed.更多还原