Enriching balancing information using the unbalance covariance matrix
Enriching balancing information using the unbalance covariance matrix
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DOI：
10.1243/09544062jmes1181
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发表时间：
2009-08
期刊：
影响因子：
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通讯作者：
S. Jiffri;S. Garvey;A. Rix
中科院分区：
文献类型：
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作者：
S. Jiffri;S. Garvey;A. Rix
摘要传统上，转子平衡仅基于来自平衡机或来自其中转子被原位平衡的机器的振动读数来执行。这些读数不能反映转子不平衡的完整状态。其原因是，较高频率模式在任何一种操作条件下对响应都没有显著贡献。测量仪器的分辨率总是有限的，并且随着对不断提高的平衡质量的需求的增长，这种仪器在降低信噪比方面变得越来越困难。当仅基于这些振动读数对转子进行平衡校正时，如果定子的特性改变，则倾向于仅激励原始配置的较高模式的不平衡分量可以对响应做出显著贡献。提出了一种新的鲁棒平衡方法。它依赖于转子不平衡协方差矩阵形式的附加信息的使用。从理论上讲，如果可以在非常高质量（和高速）的平衡机中测试所有此类转子的大样本，则可以获得该协方差矩阵。这个建议在所有的真实的情况下都是行不通的。然而，完全可以想象，用于创建转子的制造过程的建模可以提供该协方差矩阵。本文首先说明如何从建模中获得这种协方差矩阵，然后继续解释如何将协方差矩阵中的信息与特定转子的一组测量值相结合，以提供对该转子实际不平衡状态的改进估计。最后通过算例验证了所提出的鲁棒平衡方法。
Abstract Traditionally, rotor balancing is performed based only on vibration readings from either a balancing machine or from a machine in which the rotor is being balanced in-situ. These readings cannot reflect the complete state of unbalance in the rotor. The reason for this is that higher frequency modes do not make a significant contribution to response in any one operating condition. The resolution of measuring instrumentation is always limited and, as demands grow for ever-improved balance quality, this instrumentation struggles more and more with reducing signal-to-noise ratios. When balance corrections are made to a rotor based only on these vibration readings, the components of unbalance that tend to excite only the higher modes of the original configuration can make a significant contribution to response if the properties of the stator change. This article presents a novel approach to robust balancing. It relies on the use of additional information in the form of a rotor unbalance covariance matrix. In theory, this covariance matrix could be obtained if a large sample from the population of all rotors of this type could be tested in a very high-quality (and high-speed) balancing machine. This suggestion is impracticable in all real situations. However, it is entirely conceivable that modelling of the manufacturing processes used to create the rotor could deliver this covariance matrix. This article begins by illustrating how such a covariance matrix might be obtained from modelling and then goes on to explain how the information within the covariance matrix can be combined with a set of measurements from a specific rotor to provide an improved estimate of the actual state of unbalance on that rotor. Examples are included to demonstrate the proposed robust balancing method.