Signal noise reducing method for modal parameter identification

Abstract

The invention discloses a signal noise reducing method for modal parameter identification. The signal noise reducing method for modal parameter identification comprises the steps that 1, a Hankel matrix is built through a pulse response signal of a noise-containing structure; 2, a rank of the Hankel matrix is resolved, an order determination index is resolved according to the rank of the Hankel matrix, and a model order is determined through the order determination index; 3, the Hankel matrix is processed through the order determination index and structure low rank approximation to obtain a rebuilt matrix processed through low rank approximation; 4, the step 2 and the step 3 are repeatedly performed until the convergent standard is met, and therefore a noise reducing signal is obtained; 5, modal parameter identification is performed through the noise reducing signal. The signal noise reducing method for modal parameter identification has the advantages that the fact that a Frobenius norm of a difference between the Hankel matrix before being processed through noise reducing and the Hankel matrix after being processed through noise reducing approaches to be the minimum can be achieved by setting the mode of the convergent standard and structure low rank approximation, that is, the improvement of the precision of the noise reducing signal can be achieved.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a signal noise reduction method for modal parameter identification. Background technique [0002] At present, in order to ensure the safe service of large engineering structures such as bridges and offshore platforms, the structural health detection technology based on structural impulse response signals has developed rapidly. The modal parameter identification is the basic and key link of the detection technology. Therefore, it is very important to improve the accuracy of modal parameter identification. [0003] Due to the influence of test conditions, instruments and equipment, human operation, etc., there are always some uncertainties in the field vibration test experiment process, and the measured signal will inevitably be interfered by background noise. Although measures such as averaging, filtering, and masking can be used to reduce noise during data acquisition, it is im...

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Problems solved by technology

However, the result of such identification will produce false modes, and will lead to a decrease in computational efficiency, especially when the signal-to-noise ratio of the signal is low, how to distinguish a large number of false modes from real modes will become very difficult

[0004] At present, in the prior art, signal noise reduction based on low-rank approximation technology is proposed. The low-rank approximation technology uses the Hankel matrix sub-diagonal average method to identify the modal parameters of the signal after denoising. This method has a certain degree of The accuracy of modal parameter identification is improved, but the Frobenius norm of the Hankel matrix deviation before and after noise reduction in this denoising method is not the minimum value, that is, the final result is not the mathematically optimal solution, that is, the signal denoising effect there is room for improvement

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