【文章內(nèi)容簡介】 e knowledge used in the fixture design can be classified regarding the artificial intelligence technique(AI) used [8,9] and on the automation level of the design system[2]. However, whatever it is the artificial intelligence technique used and the automation level of this type of systems, the process of knowledge modelling in the fixture design is important for several reasons: the need to specify the concepts used in the fixture design。 to establish the relationships amongdifferent knowledge groups。 to develop knowledge based systems (KBS), and finally, to provide a conceptual base for reusing the knowledge. In this sense, the entities and structures defined in a knowledge model for design process of machining fixtures can be partially reused to develop new models for fixture design process, as the inspection or assembly fixture. The entities and structures reused has been defined using the method of knowledge template[4]. The work presented is a detailed proposition of the knowledge model for machining fixture design and the definition of the knowledge groups that can be reused in the inspection fixture design process, using the knowledge template method. Fig. 1 presents a general view of the contents of this ex Fig. 1. The structure of the work. planation. 2. Present state of fixture design process knowledge modelling The fixture concept arises from the need to establish a physical connection between part, and tool, and part and machinetool. This connection should fulfil some requirements for support the machining operation to carry out. The mainly functionality of the fixture is to support, locate and clamp the part to the machine tool. However, in order to interpreting correctly the needed knowledge for develop the fixture design process, it is necessary to define the basic information related with this process according to the classification exposed in Table 1. All this information has been represented in models that describe the entities, attributes and relationships between each knowledge group in the fixture design process. The definition of these models can be carried out using methodologies that describe the activities to capture, represent and reuse the knowledge of a design system, for example MOKA and CommonKADS. The MOKA methodology is based on the definition of two models. These models allow to capture and to structure the knowledge of a system. The first model, uses a group of forms (ICARE: Illustrations, Constraints, Activities, Rules,Entities) that allow to capture and to represent the knowledge in a semistructured way。 the second model allows to represent knowledge ina structured way, using the extension of UML [10]. The CommonKADS methodology proposes the use of tools and techniques to carry out the capture and representation of the knowledge. In the case of reusing knowledge, CommonKADS proposes the use of the knowledgetemplate: a knowledge template is a piece of a knowledge model, in which the data and reasoning processes can be employed in the development of other applications [3]. 3. Methodology for development a knowledge model: structural model The methodology proposed for development of a knowledge model includes the realization of two stages. The first stage represents the knowledgeof the objects like part geometry, machining process, functional and detailed fixture design,and fixture resources (see Table 1). The second stage describes the inference process (design and interpretation rules) needed to obtain a firstsolution for the machining fixture. These two stages allow to describe the structural model and behaviour model of the objects that pose the knowledge model for machining fixtures. This work is focused mainly in the descriptionof the structural model for machining fixture design process. Table 1 Knowledge group for machining fix