Two-stage noise reduction method for impact monitoring digital sequence of composite structure

Abstract

The invention discloses a two-stage noise reduction method for an impact monitoring digital sequence for a miniature digital large-scale sensor array impact monitoring system. After the miniature digital large-scale sensor array impact monitoring system acquires a digital sequence, two-stage noise suppression is carried out on the digital sequence by using the method. Haar discrete wavelet transform is adopted in the first-stage noise suppression. A noise reduction method based on the feature digital sequence is adopted in the second-stage noise suppression. The distinguishing criterion for determining the feature digital sequences is as follows: the proportion of digital sequences equal to 1 (i.e., high level) is larger than R in digital sequences the rising edges of which last for a certain length of m. Based on the method, the accuracy of impact monitoring of the miniature digital large-scale sensor array impact monitoring system can be improved and erroneous judgment and false alarm to impact are reduced.

Description

technical field [0001] The invention relates to a noise reduction method for digital sequences acquired by a miniaturized digital large-scale sensor array impact monitoring system. The miniaturized digital large-scale sensor array impact monitoring system is suitable for airborne real-time impact area monitoring and impact event recording of large aeronautical structures, and belongs to the technical field of aeronautical structure health monitoring. Through the digital sequence two-stage noise reduction method of the present invention, the noise reduction of the digital sequence can be realized without adding any signal filtering, conditioning circuit or other noise reduction hardware modules, so that the system volume and power consumption are not increased. In the case of the system, the misjudgment and false alarm of the system on the impact of the structure are reduced. Background technique [0002] Composite materials have been widely used because of their advantages ...

AI Technical Summary

Problems solved by technology

[0005] However, in order to meet the requirements of miniaturization and low power consumption, the system does not have any filtering and conditioning modules for signal noise in the hardware circuit. The external sensor array is directly connected to the comparator array in the system, and the shock location algorithm of the system relies solely on the corresponding Sequence of rising edges in the digital sequence of sensor channels

If there is a relatively large noise in the impulse response signal, these noises will also pass through the comparator to generate a digital sequence, so that the system cannot accurately locate the impact

If there is no impact, only the noise with a large amplitude will also generate a digital sequence through the comparator, resulting in a false alarm

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