Study of dynamic analysis method based on laser Doppler Vibrometry technology

Le résumé fourni par la source

• Unified Doppler signal math model. • SCI-DFT method for Vibrometry. • Bessel-based harmonic analysis. • A low-cost, FPGA-free LDVib System. Laser Doppler measurement technology is gaining increasing attention and application in modern high-precision measurement due to its excellent characteristics such as non-contact nature, fast response, high sensitivity, and high resolution. This article investigates dynamic data analysis methods based on Laser Doppler Vibrometry (LDVib) technology, reveals the physical relationship between Doppler signals and target motion parameters, and unifies the mathematical representation of output signals by the balanced photodetector. On one hand, for high-sampling-rate scenarios, which is significantly exceeding the vibration frequency, a Sampling Corrected Iterative DFT (SCI-DFT) method is proposed. This method ensures real-time processing and high-precision measurement capability through a “prediction + compensation” approach, effectively addressing the issue of non-uniform sampling in Doppler velocity sequences within the hierarchical frequency measurement scheme. On the other hand, for low-sampling-rate scenarios, which is approaching the vibration frequency level, the signal is converted into a harmonic expansion form described by Bessel functions, and an autocorrelation-based fundamental frequency extraction method is proposed. This approach effectively suppresses noise interference and enables real-time analysis. Experimental results demonstrate that the analytical methods under both conditions can quickly and accurately obtain high-precision measurement results. This study provides a theoretical foundation and technical reference for the engineering application of laser Doppler measurement technology, contributing significantly to the further development of related laser measurement techniques.

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