关键词: 模具成本, 模糊贴近度, 粗糙集, 权重分配, 指数平滑预测

Abstract: Automobile pressing moulds had various types and complex structures, and the cost was hard to estimate, thus the quotation had great difficulty. By using fuzzy mathematics theory, the die cost prediction model was constructed combining fuzzy close-degree analysis with exponential smoothing prediction. To decrease subjective factors of die similarity judgment with fuzzy mathematics, a method to calculate fuzzy nearness combined with rough set was proposed. According to die cost information database, the knowledge was classified by this mothed, and die cost information decision table was created. Objective weight distribution was made for each element of die characteristic set by using rough set attribute importance. Based on subjective weight and objective weight of experts judgment, the comprehensive weights of each element in die characteristic set was determined, and perdiction accuracy was improved. Considering the different influence degree of each die characteristic on price, the empirical formula of adjusting coefficient λ in die cost prediction was improved. The reliability and rationality of proposed method were verified by a group of die samples.

Key words: die cost, fuzzy close-degree, rough set, weight distribution , exponential smoothing prediction