Fusion Estimation of Structural Dynamic Displacement Based on Vision- and Acceleration-Based Measurements

The measurement and accurate estimation of structural dynamic displacements are of significance for the safe operation and performance evaluation of structures. The computer vision-based displacement monitoring approaches have advantages such as a high accuracy,non-contact,a low cost and easy installation,and they are superior to the traditional contact-type displacement monitoring methods in a complicated engineering environment in practice,where the equipment is difficult to install. However,the use of vision-based methods is limited by factors including image resolution and shooting frame rate to some extent. In this paper,to address the issue of low accuracy in high-frequency vibration recognition using the vision-based displacement measurement technique,a structural dynamic displacement reconstruction approach based on vision- and acceleration-based measurements is put forward by fusing the vision-based low-frequency and acceleration-based high-frequency vibration response signals,thus realizing an accurate recognition of structural dynamic displacements. First,an optical flow method is adopted to extract the structural displacement responses from the video data of structural vibration,and a forward-and-backward error and an outlier filtering mechanism are introduced to improve the feature point tracking accuracy and avoid the problem of drift. Then,a successive variational mode decomposition approach is used to extract the corresponding intrinsic mode functions(IMFs) from displacement signals obtained by quadratic integration of the vision- and acceleration-based displacements,respectively. Finally,the fused modal components are determined according to a cross-correlation function filtering mechanism,and the structural displacement responses are reconstructed by fusing the vision-based low-order and acceleration-based high-order IMFs. A shaking table test was conducted on a reinforced concrete frame structure to experimentally verify the proposed fusion estimation approach for displacements,and results indicate that the proposed approach can more accurately estimate the structural dynamic displacements than the single vision-based measurement method. In addition,the fused displacement presents a wider frequency range than the vision-based measurement result through the introduction of dynamic displacement component from the acceleration-based measurement. © 2024 Tianjin University. All rights reserved.