A monocular vision-based motion parameter measurement method for low-frequency shakers
DOI:
https://doi.org/10.24425/mms.2025.155809Abstract
Accurate measurement of low-frequency vibration parameters is critical for assessing the performance, stability, and dynamic characteristics of mechanical systems. This study proposes a monocular vision-based method for non-contact measurement of motion parameters in low-frequency shakers. The proposed method utilizes high-contrast sinusoidal fringe markers and high-resolution image acquisition to track fringe density variations caused by periodic out-of-plane motion. To enhance frequency estimation accuracy and mitigate spectral leakage, we introduce an improved time-shifting correction method, which features adaptive time-lapse selection and statistical outlier elimination to improve spectral resolution and robustness. Using a calibrated imaging model, the extracted fringe density signals are further processed to derive precise displacement and acceleration values. An experimental platform is established to validate the proposed method against conventional methods based on grating ruler displacement sensors and accelerometers. Experimental results demonstrate that the proposed method achieves high measurement accuracy, with displacement amplitude errors confined within 0.5% and total harmonic distortion values in acceleration measurements below 0.1. Additionally, the proposed method also exhibits excellent stability across a range of low-frequency scenarios. These findings confirm that the proposed method offers a reliable and non-contact alternative for low-frequency vibration measurement, holding strong potential for advancing applications in structural health monitoring, dynamic system diagnostics, and non-destructive testing.References
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