五自由度气－水润滑高速电主轴的动态特性识别

摘要

The additional masses attached to mass were taken to identify the dynamic coefficients of journal bear-ing.Since the recognition equations have a certain similarity,especially in the rigid rotor system,the matrices of recognition equations always tend to ill-conditioned,leading to a great error of the recognition algorithm.In the study,a water-gas lubricated hydrostatic spindle system with a big thrust disc,supported by a water-lubricated journal bearing and a gas-lubricated thrust bearing,is developed to improve spindle stiffness and to reduce friction power of spindle.A new identification algorithm is proposed to identify simultaneously the eighteen dynamic coef-ficients of the coupled journal and thrust bearings.The results indicate that,the estimated bearing parameters by regularization solution are in good agreement with the assumed values,and the precision of recognition method are significantly improved by using the Tikhonov regularization method.%附加不平衡质量方法是识别油膜动态特性系数常用的方法，由于识别系数矩阵存在一定的相似，特别在刚性转子系统下，识别系数矩阵往往为病态矩阵，从而影响识别算法的精度，识别算法误差很大。文中提出了一种带大推力盘的气－水混合润滑的高速电主轴结构，以提高电主轴的轴端刚度和减小主轴功耗，采用Tikhonov正则化方法建立电主轴中气体推力轴承和水滑动轴承动态系数的识别机理，解决识别系数矩阵的病态问题。计算结果表明，该识别机理大幅度提升了附加不平衡质量识别油膜动态特性系数的精度和稳定性。