基于互信息法和改进模糊聚类的温度测点优化  

Investigation on optimization of temperature measurement key points based on mutual information and improved fuzzy clustering analysis

作　　者：李艳[1] 李英浩[1] 高峰[1,2] 孟振华[1] 

机构地区：[1]西安理工大学教育部数控机床及机械制造装备集成重点试验室,西安710048 [2]陕西理工学院机械工程学院,汉中723003

出　　处：《仪器仪表学报》2015年第11期2466-2472,共7页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(51375382);陕西省自然科学基金(2013JM7014);陕西省教育厅产业化培育(2013JC27)项目资助

摘　　要：基于热误差模型进行机床热误差补偿是保证数控机床加工精度的一种有效方法,温度测点的布置和辨识会直接影响热误差建模的精确性和鲁棒性。本文提出一种互信息和改进模糊聚类法相结合的机床热关键点优化方法。以机床不同位置处的多个测点温度值及工件热变形作为分析数据,通过计算温度变量与热变形之间的平均互信息量,获得其综合关联度矩阵,确定二者之间的相关性后初选温度变量。根据改进模糊聚类法、F统计量和复判定系数对初选的温测点进行聚类,并结合温度变量与热变形之间的综合关联度值提取机床热关键点,从而实现测点优化。将基于该方法所得到的热误差模型与采用变量分组优化法获得的热误差模型进行比较,结果显示采用该方法进行热误差建模,机床X轴和Y轴的热变形预测精度得到显著提高,有利于改善加工精度。Thermal error modeling is an effective method to ensure the machining accuracy of NC machine tool thermal error using thermal error compensation,whose accuracy and robustness are directly affected by the arrangement and identification of the temperature measuring points. A new method combining mutual information and improved fuzzy clustering is presented to optimize the thermal key points of the machine tool. All temperature measuring points of the machine and thermal deformation of the workpiece are employed as analysis data,and their average mutual information is calculated to obtain their comprehensive correlative matrix and determine the correlation between them. The temperature variables are optimized. After that,the thermal key points are determined with comprehensive correlative matrix by combining the temperature variables clustered based on the improved fuzzy clustering method,the F-statistic and complex coefficient. The established thermal error model based on the method is compared with that built from the temperature key points selected using variable grouping optimization. The results show that the thermal error model is more accurate by which the prediction accuracy of thermal deformation along X axis and Y axis is greatly increased,which shows that the method is more feasible and practicable to improve the machining precision of NC machine tool.

关 键 词：互信息法 改进模糊聚类 热关键点优化 热误差模型 

分 类 号：TG502.15[金属学及工艺—金属切削加工及机床]