大型数控龙门导轨磨床几何误差建模与基于可靠性理论的精度分配  

Geometric Error Model and Precision Distribution Based on Reliability Theory for Large CNC Gantry Guideway Grinder

作　　者：余治民[1] 刘子建[1] 艾彦迪[1] 熊敏[1] 

机构地区：[1]湖南大学机械与运载工程学院,长沙410082

出　　处：《机械工程学报》2013年第17期142-151,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51175161);国家自然科学基金(51305132)资助项目;国家科技重大专项(2011ZX04003-011)

摘　　要：针对大型数控龙门导轨磨床的拓扑结构,运用多体系统理论和坐标变换方法,构建包括21项参数的几何误差传递模型,并通过试验验证模型具有理想的预测精度。在几何误差传递模型的基础上建立满足磨床设计要求的加工精度可靠性极限状态函数。对磨床工作行程内的25组位置进行误差取样,采用响应面法建立可靠性近似模型,分析每组工作位置加工精度的可靠性。以25项可靠度的均值和最小值作为磨床加工精度性能的评判指标,针对最小可靠度对应的磨床工作位置,进行灵敏度分析,利用灵敏度对影响加工精度因素的重要度进行排序。根据分析结果,遵循精度均衡原则逐步优化误差变量的分布,直至可靠度的均值和最小值均满足设计要求。通过计算实例验证大型数控龙门导轨磨床精度优化分配的可行性。According to the topology of large CNC gantry guideway grinder,a geometric error propagation model including 21 parameters is established by the theory of multi-body system and coordinate transformation method,and the model is verified by tests that it has ideal prediction accuracy.Limit state function of the reliability of machining accuracy to meet grinders design requirements is built on the geometric error propagation model.Reliability approximately model is established by response surface method with error samples from 25 sets of position of the grinder working stroke and the reliability of the machining accuracy of each group working position is analyzed.With the mean and minimum of 25 items of reliability as the index for judging the machining accuracy performance of grinders,the sensitivity analysis is obtained for the minimum reliability corresponding to the grinder working locations.The importance degrees of the factors that affect machining accuracy are sorted by sensitivity.According to the results of the analysis,the distribution of error variables is optimized gradually by following the principle of accuracy proportionality until the mean and minimum of the reliability meet the design requirements.The optimization in precision distribution for large CNC gantry guideway grinder is verified feasible through numerical examples.

关 键 词：误差传递模型 极限状态函数 响应面法 灵敏度分析 精度优化分配 

分 类 号：TH115[机械工程—机械设计及理论]