摘要
下死点动态精度是评价压力机性能的一项重要指标。为了全面地评价压力机下死点动态精度,引入变权法,提出了一种基于层次分析法的模糊综合评价体系。该体系以下死点重复精度、下死点位移漂移量、下死点位移均方差为评价指标,运用基于几何平均的AHP解决可能出现的逆序问题,利用梯形分布函数确定隶属度。同时,引入变权法调整各指标权重以解决因经典AHP权值固定而导致评价结果对低指标值项不敏感的问题。最后,以某型高速压力机为研究对象,运用该方法评价了其下死点精度。结果表明,该方法能突出评价值较低的指标,经调权后其权重变化率最高可达76.61%,增强了评价的合理性。
The dynamic precision of bottom dead center( BDC) is an important indicator to evaluate the performance of mechanical press.In order to comprehensively evaluate the BDC precision of press,variable weight method was introduced,and a fuzzy comprehensive evaluation system based on Analytic Hierarchy Process( AHP) was proposed. Taking the repeat accuracy,drift offset and mean square error of displacement of slider BDC as the evaluation index,the possible reversal issues was solved by geometric-weighted AHP,and the degree of membership was determined by trapezoidal distribution function. In the meanwhile,each index weight was adjusted by the variable weight method to solve the problem that the evaluation result was not sensitive to the index with low scores due to the fixed weights of classical AHP. In the end,for a certain type of high-speed press,the precision of BDC was evaluated. The result shows that this method can highlight the index with low scores,and the change rate of its weight can up to 76. 61% after applying variable weight method. Thus,the rationality of evaluation is enhanced.
引文
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