针对带噪加速度信号的积分问题，新近发展的有效频段法相对于传统的频率截止法，积分精度和抗噪性得到了较大改善。但多个分析频率范围需要人为指定，且高噪声的适应性仍较差，不利于工程实践。基于加速度信号的Welch功率谱，提出改进的有效频段法。首先针对Welch功率谱曲线，综合应用5%峰值阈值和邻近波谷频率，实现分析频率范围的自动定义。继而提出基于Welch功率谱曲线和基于Welch功率谱开方曲线的两种不同形态拟合方法，实现有效频段的自动识别。最终进行有效频段内的频域积分，得到相应的速度和位移信号。通过数值模拟算例，对比考察原有效频段法和改进方法在多频激励和随机激励下的积分效果。结果表明，相对于原方法，改进方法可以实现加速度积分的全程自动分析，且抗噪性能进一步加强，其中基于Welch功率谱曲线和基于Welch功率谱开方曲线的形态拟合分别适用于高噪声下的多频激励情况和随机激励情况。
关键词：加速度积分；频域积分；有效频段；Welch功率谱
Abstract
For the integration of noisy acceleration signals, the newly developed effective frequency band method has greatly improved the integration accuracy and noise immunity compared with the traditional frequency cutoff method. However, multiple frequency ranges for analysis need to be artificially specified and the adaptation to high noise is still poor, which is not conducive to engineering practice. Based on the Welch power spectrum of acceleration signals, an improved effective frequency band method is proposed. Firstly, with the Welch power spectrum curve, the 5%-peak threshold and the neighboring trough frequencies are integrated and applied to achieve the automatic definition of multiple frequency ranges for analysis. Following that, two different morphological fitting methods based on the Welch power spectrum curve and the Welch power spectrum squared curve, respectively, are proposed to realize the automatic identification of the effective frequency bands. Finally, the corresponding velocity and displacement signals are obtained through frequency-domain integration within the effective frequency bands. Through numerical simulation examples, the integration effects of the original effective frequency band method and the improved method are examined comparatively under multi-frequency excitation and random excitation. The results show that, in contrast to the original method, the improved method can realize the whole-process automatic analysis of acceleration integration, and the noise immunity is further enhanced, in which the Welch power spectrum curve based morphological fitting is applicable to the case of multi-frequency excitation under high noise, as well as the Welch power spectrum squared curve based one to the case of random excitation.
Key words: acceleration integration; frequency domain integration; effective frequency band; Welch power spectrum
关键词
加速度积分 /
频域积分 /
有效频段 /
Welch功率谱
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Key words
acceleration integration /
frequency domain integration /
effective frequency band /
Welch power spectrum
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