Noncontact Structural Displacement Measurements Using a Low-Cost Motion Tracking System

Abstract

Structural health monitoring (SHM) depends on precise displacement measurements to evaluate a structure’s condition. Current measurement systems face challenges such as contact-type restrictions, high costs, uniaxial limitations, and significant computational power requirements. A novel low-cost, non-contact displacement measurement system, called the HTC-VTS (Vive Tracking System), developed by Hongda International Electronics Co., Ltd. (New Taipei City, Taiwan), is proposed. The system setup and data acquisition of the HTC-VTS for SHM involve coordinate transformations to convert six degrees of freedom (DOFs) from raw motion data into 3-DOF structural displacement measurements. The HTC-VTS was experimentally validated using laboratory-scale free vibration tests on a cantilever beam and shaking table tests with actual bridge displacement measurements, demonstrating satisfactory performance in both scenarios. The proposed system expands the potential for cost-effective motion capture systems in both experimental and real-world structural applications.