Development of an Expert System for Drawing Die Structure Design Based on Functional Features

[[abstract]]本研究的目的是建構機能特徵為基礎的堆疊方式，來設計引伸模具結構之專家系統。在機能的推演方面，本文以機能樹分析、機能拆解及幾何分析等解析程序，取得引伸模具結構中所有的機能特徵及其主要控制參數，並將其建置成機能特徵資料庫；在堆疊的設計方面，使用者是以平面配置設計（layout design）的方式進行模具結構之堆疊設計，系統透過呼叫CATIA應用程式介面（application program interface API），從圖形使用者介面的2D圖元驅動CATIA之3D模型，同時在程式運行過程中，從機能特徵模組中載入模具設計準則與規範，建立機能特徵之設計規則；在參數的定量方面，本文以模面肋結構為例，應用MATLAB模糊推論系統（fuzzy inference system FIS）於模具設計規範之語言變數的決策，提供使用者定量化的肋條間距設計值。本引伸模具結構設計專家系統包含圖形使用者介面、模具設計知識庫、機能特徵資料庫與模組及定性設計參數決策之模糊邏輯控制器等。 本論文以汽車後艙蓋外鈑之引伸模具為實務設計案例，驗證一般設計流程和專家系統方式進行模具結構建構之效能差異，結果顯示，以本專家系統進行模具結構設計，僅需一般設計流程之工作時數的十分之一，因此，企業若應用此模具結構設計專家系統於模具設計階段，將能有效提升模具設計品質與效率。[[abstract]]The purpose of this research project is to construct an expert system for designing the structure of a drawing die which is based on a functional stack-up approach By performing a functional tree analysis a functional decomposition and a geometric analysis design engineers are able to identify a particular drawing die structure’s functional features and their main control variables which are then used as the basic units for the stack-up design The user can stack up functional features through the layout design panel of the system When a 2-D pattern has been dragged onto the design panel a 3-D model will be created by the CATIA application program interface (API) At the same time design rules for functional features will also be created from the functional feature module The die face rib structure of a drawing die is taken as an example of quantitative parameters The fuzzy inference system (FIS) of MATLAB is used to determine the linguistic parameters for the design rules of the die rib structure to provide users with quantitative rib spacing design parameters The expert system for designing the structure of a drawing die includes a graphical user interface a die design knowledge base a functional feature library and module and a fuzzy logic controller for the determination of the quantitative design parameters This research project uses the design of a drawing die structure for a vehicle trunk lid as a concrete example to demonstrate the power of the expert system as compared to that of general design procedures Based on our experimental results the expert system for designing the structure of a drawing die can reduce the structure design time by 90% Therefore our system provides enterprises with an efficient flexible and accurate stack-up system for designing die structure