外文翻译---基于知识工程的汽车覆盖件冲压路线分析-汽车设计(编辑修改稿)

外文翻译---基于知识工程的汽车覆盖件冲压路线分析-汽车设计(编辑修改稿)内容摘要：

ing knowledge multiexpression format, the integrated information model of process planning is built based on a feature model. For the hierarchy and framework of the features, semantic and object oriented methods are adopted to express knowledge and establish an information model in which process knowledge, . database, parameter, rules, and experience, act as rules and attributes of the objects, and where whole product knowledge acts as a framework for relationships of objects. With a process information model, the process planning can be pleted through knowledgereasoning and decisionmaking based on knowledge encapsulated in the objects. The PCS is a key point to ensure process planning is integrated and consistent。 it manages the process information model, process planning to generate stamping process plans and detail design, and controls the changes of the planning. In IMM, the PCS es into being dynamically along with the process planning. If one part of PCS is created, it will monitor and control relevant planning and information subsequently. When results of process planning are deleted, the corresponding PCS part will fade away accordingly. The LE provides several methods to deal with the links among process planning procedures, the geometry between product and detail design of work pieces. To achieve intelligent process planning for large plicated stampings, there are problems to solve, . linking of process planning procedures, the geometry link between product and detail design of work pieces. The LE provides several methods to deal with these links, . parameters variable link, data structures link, and geometrical link. The PPO is a methodology of design optimum for plex engineering, which can deal with the plicated optimization problem of process planning in an economic view. The framework of CAPP system based KBE The stamping CAPP system for automobile panels based on the intelligent master model above consists of several stages such as stamping features extraction from product data, operation features reasoning from stamping features to form a process information model, process planning to get the sequence of operations and relevant tools, detail design for work pieces, simulation for detail design, and finally the process plans and 3D dieface model generation which is shown in . It is a tangible activity level to control and frame a CAPP system for automobile panels. In the CAPP system, stamping process planning of automobile panels needs to first establish a process information model based on a 3D model product and feature technology. Stamping features are extracted, and operation features are attained subsequently. The features all carry knowledge about themselves, the process and constraints. Then the PIM and PCS are established. Thereafter, the sequence planning is setup based on PIM and knowledge such as operation sequence rules, operation bination guides and reasoning methods, and then the dies and machinery are options. Along with the process of the planning, PCS, PPO and LE of IMM are built by knowledge driving. PCS consists of an integrated collection of tasks that can initiate, control, manage, evaluate and update all the planning information and results timely. PPO optimizes process paths and enterprises resource environments, and PCS and PPO carry out the optimization and find the optimal solution. PCS and LE make process planning associated and linkable. 4 Key points of process path generation Unigraphics has several features that provide a subset of the capabilities of a KBE language —UG/KFL, which provides a way to specify knowledge rules that can cover all Unigraphics applications. The stamping CAPP system for automobile panels has been developed based on the frameworks advanced above, which choose C and UG/KF language as t he implementation language, a nd ACCESS as its database o n t he UG/CA D development environment. UG/Open and UG/Open++ allow custom i zation and extension of Unigraphics using a standard procedural language (C and C++). UG/KFL provides a way to specify knowledge rules that can cover all Unigraphics applications. Rules of UG/KFL are easily written by the developer, easy to read, understandable, and reusable by the user. Furthermore, UG/Open can be integrated with KBE by accessing C programs from the KBE language described under External Function. For access to named attributes from C, there will be a utility program that takes a design definition in the language and produces C bindings to access the attributes of an object instance of that design. The access consists of functions and methods for getting and setting the value of the named attributes of object instances. Additionally, there are UDF and UDO in UG/ CAD and UG/KF, which can be dealt with by UG/Open and UG/KF. What is more, Unigraphics is integrated with many other knowledge tools and sources, such as spread sheets, other ICAD KBE language systems, finite element analysis, CAM, etc. Stamping feature To generate appropriate process plans, the product data requires the original inputs, which includes the geometry, topology, tolerance, material and quantity of product. Based on the feature technology and stamping technology, a stamping feature is the portion of a part which can be formed by means of certain stamping operations. For ex ample, a drawn feature or bend feature is defined as the main feature, which is to describe the near shape of a ponent, while flange, hole, emboss, bead, notch and flangehole are defined as the auxiliary ones, which are required to describe the local part of the final shape. Using feature technology and the geometry extraction method, the stamping design features, such as the main forming feature (. drawing, bend), flange, hole, emboss, bead, notch, and so on, can be extracted from a 3D solid。