Phase-locked 신호 및 영상위상 기반 변위 측정기법을 이용한 고속 회전 블레이드 상태 모니터링 기법 = High-speed Rotating Blade Condition Monitoring Technique Using Phase-locked Signal and Phase-based Displacement Measurement Method

국문 초록 (Abstract)

카메라 시스템을 활용한 변위 측정기법은 접촉식 센서의 단점을 보완하면서, 영상 전역의 변위 측정이 가능하여 다양한 구조물의 상태진단 연구에 활용되고 있다. 하지만, 카메라 시스템을 이용해 회전 상태의 구조물 측정 시 블러 등의 문제가 발생할 수 있다. 본 연구는 운용 조건에서도 적용 가능한 카메라 기반의 상태진단 기법을 제시한다. 먼저, phase-locked 신호를 이용하여 서브픽셀 단위의 미소 변위만을 갖는 정지 영상을 생성한다. 이후 위상 기반 광학 흐름(Phase-based Optical Flow, POF) 기법을 사용하여 구조물의 변위를 측정하고, 이를 활용하여 상태진단을 수행한다. 이때, POF 기법을 통해 측정된 전역(full-field) 변위를 기반으로 결함을 시각화하여 구조물의 상태를 평가할 수 있다. 실험 결과, 회전 중인 구조물의 볼트 풀림 결함을 정확히 탐지하고 위치를 추정할 수 있었으며, 이는 다양한 회전체의 효율적인 모니터링에 기여할 수 있으리라 판단된다.

다국어 초록 (Multilingual Abstract)

Displacement measurement techniques using camera systems reduce the need for contact sensors and enable high-resolution, non-contact displacement measurements, which are widely used for structural health monitoring. However, measuring rotating structures can cause issues such as motion blur. This study presents a camera-based condition-monitoring technique applicable to operational conditions. First, a phase-locked signal is used to generate stationary images showings the sub-pixel-level micro-displacements of rotating objects. Subsequently, the phase-based optical flow (POF) method measures the displacement of the structure and is used for condition monitoring. The POF technique allows defect visualization by analyzing full-field displacement measurements, thereby enabling the evaluation of the structural condition. Experimental results demonstrate that the proposed method accurately detects and locates bolt-loosening defects in rotating structures, contributing to effective monitoring of rotors in applications such as urban air mobility (UAM).

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