Noncontact Dynamic Displacement Measurement of Structures Using a Moving Laser Doppler Vibrometer

Garg, Piyush; Moreu, Fernando; Ozdagli, Ali I.; Taha, Mahmoud Reda; Mascareñas, David

doi:10.1061/(asce)be.1943-5592.0001472

Cited by 55 publications

(27 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Laser Doppler Vibrometer (LDV) measures target vibration using frequency change in the transmitted laser signal due to the Doppler effect. LDV as a non-contact sensor has been used for bridge displacement measurement [ 50 , 51 ]. While this device still needs to be placed on a rigid surface near the target, the operation distance is usually long and is hindered less by the terrain conditions.…”

Section: Introductionmentioning

confidence: 99%

Measuring Transverse Displacements Using Unmanned Aerial Systems Laser Doppler Vibrometer (UAS-LDV): Development and Field Validation

Garg

Nasimi

Ozdagli

et al. 2020

Sensors

Self Cite

View full text Add to dashboard Cite

Measurement of bridge displacements is important for ensuring the safe operation of railway bridges. Traditionally, contact sensors such as Linear Variable Displacement Transducers (LVDT) and accelerometers have been used to measure the displacement of the railway bridges. However, these sensors need significant effort in installation and maintenance. Therefore, railroad management agencies are interested in new means to measure bridge displacements. This research focuses on mounting Laser Doppler Vibrometer (LDV) on an Unmanned Aerial System (UAS) to enable contact-free transverse dynamic displacement of railroad bridges. Researchers conducted three field tests by flying the Unmanned Aerial Systems Laser Doppler Vibrometer (UAS-LDV) 1.5 m away from the ground and measured the displacement of a moving target at various distances. The accuracy of the UAS-LDV measurements was compared to the Linear Variable Differential Transducer (LVDT) measurements. The results of the three field tests showed that the proposed system could measure non-contact, reference-free dynamic displacement with an average peak and root mean square (RMS) error for the three experiments of 10% and 8% compared to LVDT, respectively. Such errors are acceptable for field measurements in railroads, as the interest prior to bridge monitoring implementation of a new approach is to demonstrate similar success for different flights, as reported in the three results. This study also identified barriers for industrial adoption of this technology and proposed operational development practices for both technical and cost-effective implementation.

show abstract

Section: Introductionmentioning

confidence: 99%

Measuring Transverse Displacements Using Unmanned Aerial Systems Laser Doppler Vibrometer (UAS-LDV): Development and Field Validation

Garg

Nasimi

Ozdagli

et al. 2020

Sensors

Self Cite

View full text Add to dashboard Cite

show abstract

“…The second category of displacement measurement methods refers to global position systems (GPS) [12][13][14][15][16][17], vision systems [18][19][20][21], radar systems [22][23][24], and laser systems [25,26]. These systems can provide accurate displacement in a noncontact manner.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Lateral Dynamic Displacement of High-Rise Buildings under Wind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer

Liu

et al. 2020

Remote Sensing

View full text Add to dashboard Cite

This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions.

show abstract

“…Contact type displacement sensors such as LVDT (linear variable differential transducer) connect a measurement point and a reference point physically. This connecting work can be very cumbersome and complex, especially for civil structures where the measurement and the reference point are too far to connect the two points with a sensor [ 2 , 3 ]. Noncontact type displacement sensors, such as laser Doppler vibrometer (LDV) and light detection and ranging (LiDAR), remove the shortcomings of the contact type sensors by emitting laser on a surface of a structure and measuring the time-of-flight of the laser [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Displacement Estimation for Long-Span Bridges Using Acceleration and Heuristically Enhanced Displacement Measurements of Real-Time Kinematic Global Navigation System

Kim

Sohn

2020

Sensors

View full text Add to dashboard Cite

In this paper, we propose a dynamic displacement estimation method for large-scale civil infrastructures based on a two-stage Kalman filter and modified heuristic drift reduction method. When measuring displacement at large-scale infrastructures, a non-contact displacement sensor is placed on a limited number of spots such as foundations of the structures, and the sensor must have a very long measurement distance (typically longer than 100 m). RTK-GNSS, therefore, has been widely used in displacement measurement on civil infrastructures. However, RTK-GNSS has a low sampling frequency of 10–20 Hz and often suffers from its low stability due to the number of satellites and the surrounding environment. The proposed method combines data from an RTK-GNSS receiver and an accelerometer to estimate the dynamic displacement of the structure with higher precision and accuracy than those of RTK-GNSS and 100 Hz sampling frequency. In the proposed method, a heuristic drift reduction method estimates displacement with better accuracy employing a low-pass-filtered acceleration measurement by an accelerometer and a displacement measurement by an RTK-GNSS receiver. Then, the displacement estimated by the heuristic drift reduction method, the velocity measured by a single GNSS receiver, and the acceleration measured by the accelerometer are combined in a two-stage Kalman filter to estimate the dynamic displacement. The effectiveness of the proposed dynamic displacement estimation method was validated through three field application tests at Yeongjong Grand Bridge in Korea, San Francisco–Oakland Bay Bridge in California, and Qingfeng Bridge in China. In the field tests, the root-mean-square error of RTK-GNSS displacement measurement reduces by 55–78 percent after applying the proposed method.

show abstract

Noncontact Dynamic Displacement Measurement of Structures Using a Moving Laser Doppler Vibrometer

Cited by 55 publications

References 34 publications

Measuring Transverse Displacements Using Unmanned Aerial Systems Laser Doppler Vibrometer (UAS-LDV): Development and Field Validation

Measuring Transverse Displacements Using Unmanned Aerial Systems Laser Doppler Vibrometer (UAS-LDV): Development and Field Validation

Estimation of the Lateral Dynamic Displacement of High-Rise Buildings under Wind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer

Dynamic Displacement Estimation for Long-Span Bridges Using Acceleration and Heuristically Enhanced Displacement Measurements of Real-Time Kinematic Global Navigation System

Contact Info

Product

Resources

About