Dynamic Response Measurement and Cable Tension Estimation Using an Unmanned Aerial Vehicle

Abstract

Since all structures vibrate due to external loads, measuring and analyzing vibration data is a representative method of structural health monitoring. In this paper, we propose a non-contact cable estimation method using a vision sensor mounted on an unmanned aerial vehicle. A target cable among many cables can be identified through marker detection. In addition, the motion of the structure can be quickly captured using the extracted feature points. Although computer vision can be used to transform displacements of multiple axis, in this study, only the vertical displacement is considered to estimate tension. Finally, the cable tension can be estimated via the vibration method using the modal frequencies derived from the cable displacement. To verify the performance of the proposed method, lab-scale experiments were carried out and the results were compared with the conventional method based on the accelerometer. The proposed method showed a 3.54% error compared with the existing method and confirmed that the cable tension force can be estimated quickly at low cost.

Yoke-Type Elasto-Magnetic Sensor-Based Tension Force Monitoring Method for Enhancement of Field Applicability

“…where V is the induced voltage, N is the number of turns of the coil, and is the rate of change of the magnetic flux over time. Magnetic induction B is the flux density, which is equal to Equation (4).…”

“…To prevent this, several precedents exist for measuring and monitoring the tension in tension materials. Studies have been conducted on estimating the cable tension of bridges using vision sensors on unmanned aerial vehicles [ 4 ], diagnosing defects in steel wire ropes using multichannel magnetic flux leakage (MFL) sensor-based nondestructive testing techniques [ 5 ], developing a tension monitoring system for cable-stayed bridges using wireless smart sensors and vibration-based tension estimation methods [ 6 ], and tension material tension force monitoring in PSC girders and cable-stayed bridges using FBG sensors [ 7 , 8 ]. Moreover, in recent years, tension material monitoring research has expanded to other fields, such as aerospace, mooring lines in subsea structures, and nuclear containment building.…”

Computer Vision-Based Bridge Inspection and Monitoring: A Review

“…Bridges play a key role in the transportation infrastructure system [ 1 , 2 , 3 ]. A bridge structure is subjected to the coupling effects of multiple factors such as wind, earthquakes, impact, and vehicle load.…”