【作者】 罗忠诚；

【导师】 彭芳瑜；

【作者基本信息】 华中科技大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 STEP-NC 是国际标准化组织最近制定的CAM 与CNC 之间新的数据接口标准,是STEP 在CNC 领域的扩展。STEP-NC 以面向对象的形式将产品的设计信息与制造信息联系起来,消除CAX 与CNC 之间的信息流瓶颈。基于STEP-NC 的新一代数控系统的出现将对制造装备智能化、集成化、网络化的实现奠定坚实的基础。STEP-NC 数控系统的数控加工程序是AP238 文件,它包含了加工一个零件所需的全部几何信息和工艺信息。对AP238 文件的译码处理不能像G 代码那样逐行解释执行,而只能采取编译的方法,因此,STEP-NC 数控系统的译码处理系统称之为编译器。本文围绕STEP-NC 车削数控系统编译器的设计与实现开展了以下工作: 研究STEP 标准及其一致性测试原理与方法,分析了AP238 中性文件的结构,将STEP-NC AP238 一致性测试划分为三个功能模块:语法测试模块、结构测试模块和语义测试模块。在语法测试模块研究中,采用计算机编译技术,并结合被测文件的结构特点,研究了对文件标识符、关键字等测试点的测试方法。阐述了STEP-NC 产品数据模型以及AP238 加工程序的结构层次关系,建立了EXPRESS 语言数据结构到Python 语言的映射,利用数据字典将STEP-NC 的数据的层次关系保存下来建立了拓扑数据表,实现了AP238 文件的信息提取。根据STEP-NC 定义的加工特征、加工操作以及加工策略,将走刀路线大致分为平行轴向(或径向)走刀法以及沿轮廓线走刀法,研究了两种走刀路线的具体算法,实现了基于STEP-NC 车削加工特征的刀位轨迹的自动生成。最后研究了基于STEP-NC 的车削数控系统的体系结构,分析了STEP-NC 车削数控系统编译器的功能模块,并给出了编译器的具体实现,为STEP-NC 车削数控系统软件平台的研究和开发奠定了基础。更多还原

【Abstract】 STEP-NC is a new data interface standard between CAM and CNC that is established by the International Standards Organization recently. It is a STEP expansion in the field of CNC. STEP-NC relates design information and manufacturing information of the products in the form of oriented object, dispels the information flow bottleneck between CAX and CNC. The appearance of new generation based on STEP-NC will establish solid foundation for manufacture equipment in realization intelligent, integrated, networked. The machining procedure of STEP-NC numerical control system is the AP238 file that includes all the geometry information and craft information for machining the part. The decipher of AP238 file can’t explain and execute line by line as G Code, and can only compile, thus the decipher process system of STEP-NC numerical control system was called as the compiler. The following work is accomplished around the design and realization of the compiler of the STEP-NC turning NC system in this thesis: Firstly, the thesis researches the STEP standard and its principle and method of conformance testing, analyzes the structure of AP238 neutral file, and divides STEP-NC AP238 conformance testing into three function modules: Syntax testing, Structure testing and Semantic testing. In the Syntax testing module, the testing method of file identifier, key word, etc, which adopts computer compile technology, combining the structure characteristic of examined file, is researched. The STEP-NC products data model and the structure level relation of AP238 processing procedure are described, and the mapping from EXPRESS language data structure to Python language is built up. The topological data list is set up by utilizing data dictionary which saves level relation of data of STEP-NC, and the information extraction of AP238 file is realized. The tool path is approximately divided into parallel axial (or radial) and along profile according to the machining_feature, machining_operation and machining_strategy that are defined in STEP-NC. Two algorithms of tool path are developed in the thesis and the automatic generation of the tool path based on the machining_feature of the STEP-NC turning is fulfilled. Finally, the system structure of turning NC system based on STEP-NC is researched. After analyzing the compiler function module of STEP-NC turning NC system, the realization of the compiler is brought out. Base on above research, the development foundation of STEP-NC turning NC systems software platform is established.更多还原