Research Areas
SITL's primary research efforts have been in the interdisciplinary area of smart infrastructures, with particular emphasis on smart sensing technology and big data fusion analysis for structural condition assessment to provide resilient and sustainable civil infrastructure systems. Our contributions in this area include the development of sensing technologies using wireless smart sensors and computer vision, development of data analytics tools for structural condition assessment, and conducting full-scale testing of the developed sensors and tools.
Next Generation Wireless Smart Sensor
|
SITL is advancing a next-generation wireless smart sensor platform engineered for broad industry adoption, paving the way for Big Data-driven, self-aware AI in infrastructure maintenance. The latest model, JANET, integrates a powerful 6-channel strain sensor, a 3-channel accelerometer, and adaptable ports for seamless integration with various sensor types. This versatile platform empowers real-time data collection and analysis, setting new standards in intelligent infrastructure monitoring.
|
Data Fusion for Reference-free Displacement Estimation
Structural displacement is very important for evaluating current structural condition. The most precise way for measuring displacement on civil engineering structures is direct measurement (e.g., using LVDTs and LDVs); however, these approaches are expensive and may be very challenging to install on larger structures.
To address this issue, SITL has developed a reference-free displacement measurement that seeks combined use of accelerometers and strain sensors. The proposed strategy fuses the two indirect methods, strain and acceleration, to achieve a combination which compensates for their respective weaknesses. Acceleration-based estimation provides high-frequency information, and the strain-based method makes the estimation of low-frequency components possible. The reference-free displacement estimation method was validated on a full-scale suspension bridge (Sorok Bridge, Korea), demonstrating the method’s efficacy for bridge health monitoring. Shown below are the comparison of displacement measurement from laser-based, DGPS, and proposed method (Data Fusion). The proposed reference-free method shows very good agreement with laser sensor in both time and frequency domain.
To address this issue, SITL has developed a reference-free displacement measurement that seeks combined use of accelerometers and strain sensors. The proposed strategy fuses the two indirect methods, strain and acceleration, to achieve a combination which compensates for their respective weaknesses. Acceleration-based estimation provides high-frequency information, and the strain-based method makes the estimation of low-frequency components possible. The reference-free displacement estimation method was validated on a full-scale suspension bridge (Sorok Bridge, Korea), demonstrating the method’s efficacy for bridge health monitoring. Shown below are the comparison of displacement measurement from laser-based, DGPS, and proposed method (Data Fusion). The proposed reference-free method shows very good agreement with laser sensor in both time and frequency domain.
ROBOTICS for SHM
Conducting modal analysis is very critical for identifying structural condition. Traditional approach deploys dense array of sensors directly on a structure to extract modal parameters. Using computer-vision and drones, we are trying to conduct modal analysis in a non-contact manner without cumbersome process of installing sensors on a structure. We are now working toward enabling drone-based structural health monitoring focusing on analyzing dynamics of a structure.
UAV is capturing motion of a building structure in a reference-free manner
|
Captured and detected motion of a building structure. This movie was taken by an UAV (Phantom 3)
|
JAXON: Remote Bridge Bearing Monitoring System
We have recently deployed compact IoT vision sensor named JAXON on a bridge in South Korea. JAXON is developed to take pictures of a target installed on a bridge bearing periodically in low power operation, and 6DOF motions are extracted from the pictures that are uploaded from the JAXON. The cloud-sever makes use of computation resources to extract highly accurate 6DOF motion and the data is automatically recorded in a Database for monitoring.
Computer Vision for Marker-free Measurement System
SITL is developing non-target vision system for structural displacement measurement especially for bridges built over channels or highways. Non-target system literally does not require any marker installation that is typically required for conventional vision-based method. The developed system emit laser with know geometry and directly convertthe amount of pixel change into acutal displacement. We have validated the performace of the device upto 50 m apart from the structure achieving minimum resolution of 0.01 mm.
Comparison between reference-free method (data fusion) and direct method (Laser)