| With the continuous development of social productivity and the increasingly strong personalization and diversification of user requirements,the transformation and upgrading of the manufacturing industry from mass production to multi-variety small batch customization and personalized production mode have become an inevitable trend.As the core products of the manufacturing industry,mechanical products involve many aspects of human life,and their personalized and customized requirements continue to expand.In the new production model and market demand,mechanical product manufacturing enterprises must maintain or enhance their core competitiveness through high efficiency,high quality,and low-cost product development methods.In this context,reusing successful historical design cases to deal with new design requirements has become important for enterprises to respond quickly to the market and maintain production vitality.At present,mechanical product design reuse technology is mainly focused on the design process of the same series or family of products.However,with the continuous development of social economy and science and technology,the structure and function of mechanical products are becoming more and more complex,and the reserve of historical product design cases to meet new customized requirements in enterprises is low,which limits the enterprises to performing the design reuse of the historical design cases.Therefore,this paper proposes the concept of design reuse of mechanical product meta-action units.First,the mechanical product is decomposed into meta-action units with independent structures and simple functions.Then,the meta-action units are taken as the object of design reuse so as to improve the universality of the reused structure and further expand and enhance the application range and utilization rate of design reuse in mechanical product design.This dissertation discusses and studies the key technologies of design reuse of meta-action units from the four aspects: unit structure and information analysis,unit modeling,unit retrieval,and unit design change.The details of this paper are as follows:(1)Structure acquisition and information analysis of meta-action units.The "Function-Motion-Action"(FMA)decomposition technology is applied to decompose the functions of mechanical products into meta-actions,and then the physical structures required to ensure the normal realization of meta-action,i.e.,meta-action unit,are analyzed,and thus to establish the structural concept model of the meta-action unit.Then,the matching relationship between parts in mechanical products is analyzed,and the component parts of meta-action units are identified using Breadth First Traversal(BFT)strategy,which helps engineers to obtain the meta-action unit structure.Subsequently,the formation process of meta-action unit information,the categories and connotations of internal and external information in the meta-action unit,and the characteristics of information are analyzed in detail.As a result,the multi-dimensional and complex information composition of meta-action units oriented to design reuse is obtained.(2)Domain ontology modeling technique of meta-action units for design reuse.The ontology theory is used to express the multidimensional and complex information of meta-action units with the goal of design reuse.First,based on the ontology theory,the concept and definition of meta-action unit domain ontology are proposed;and the construction principle,construction method,construction tool,and description language of meta-action unit domain ontology are explained and selected.Then,the main tasks of meta-action unit domain ontology are determined according to the definition of meta-action unit domain ontology construction.Furthermore,the main concepts,the relationships among concepts,and the concept attributes in the multidimensional information of the meta-action unit are also analyzed.The concepts,relationships,and attributes in the meta-action units are related by the protégé tool.Thus the meta-action unit domain ontology model is constructed and visualized,which provides the framework for the normalized representation of multidimensional and complex information of meta-action units.Finally,the meta-action unit case information is expressed and stored through the instance filling of the ontology model.(3)Case retrieval of reusable meta-action units based on similarity and applicability evaluation.First,the user requirements are collected and analyzed,and the requirement standardized model is employed to standardize the user requirements to establish the design requirement ontology model as the target case of case retrieval.Then,considering the structural similarity and semantic similarity between the target case and the meta-action unit history case in the case base,the historical cases of the meta-action units that can be reused are preliminarily determined.Furthermore,a calculation model of feature attribute similarity of meta-action units based on heterogeneous information analysis is proposed,and the calculation method of feature attribute similarity between target cases and historical cases under multiple information type scenarios is defined.The objective weight of each feature attribute is obtained by using information entropy to perform the fusion calculation of feature attribute similarity.Furthermore,WASPAS is applied to evaluate the applicability of reusable meta-action units,which clarifies the resue difficulty of different historical meta-action units.Considering the calculation results of feature attribute similarity and applicability of historical meta-action units,the comprehensive availability of historical meta-action cases is determined,and the historical cases of meta-action units that are most suitable for design reuse are extracted.(4)Design change technique for reusing meta-action units based on design requirements.First,the differences between the reused unit and the design requirements are analyzed to obtain the attribute items in the outer layer information of the meta-action unit that do not meet the design requirements.Second,based on the attribute value calculation and feature analysis of the different attributes,a decision table is constructed to conduct the change making-decisions for the different items.Third,The outer attributes that need to be changed are extracted as the change requirements set,and then the mapping relationship between the outer attributes and the inner attributes is established to obtain the change requirements of the inner attributes of the unit,which are used as the design change source of the reused unit.Fourth,considering the attribute relationship of the reuse unit,a directed graph model of change propagation caused by the change source in the meta-action unit is established using graph theory technology.With the help of Interpretative Structural Modeling(ISM)theory,the hierarchical structure of the directed graph model is analyzed to obtain the change propagation path within the reuse unit.Fifth,the change attributes and change requirements in the propagation model level by level along the change propagation path are analyzed to establish a list of change items of reused meta-action units.Finally,the reuse units are redesigned according to the list of change items to generate a new meta-action unit that meets the design requirements. |
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