• 상하수도학회지
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• 제38권2호
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• pp.83-93
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• 2024

In this study, we present a sewer pipe inspection technique through a combination of active sonar technology and deep learning algorithms. It is difficult to inspect pipes containing water using conventional CCTV inspection methods, and there are various limitations, so a new approach is needed. In this paper, we introduce a inspection method using active sonar, and apply an auto encoder deep learning model to process sonar data to distinguish between normal and abnormal pipelines. This model underwent training on sonar data from a controlled environment under the assumption of normal pipeline conditions and utilized anomaly detection techniques to identify deviations from established standards. This approach presents a new perspective in pipeline inspection, promising to reduce the time and resources required for sewer system management and to enhance the reliability of pipeline inspections.

• 한국가스학회지
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• 제21권1호
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• pp.18-26
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• 2017

현재의 초음파 두께 측정에 기반한 배관 감육 검사 속도를 개선하기 위해 배관 쉘 진동 모드의 고유 진동수 변화를 이용한 감육 검사 기법을 제안하였다. 감육이 발생한 부위의 축방향 수직 단면의 두께는 원주 방향을 따라 불균일하게 변화하는데, 두께가 균일한 경우에 비해 쉘 모드의 고유 진동수가 감소하거나 두 개 이상으로 분기됨을 확인하였다. 배관의 고유 진동수는 한 번의 측정으로도 평가할 수 있으므로, 제안한 방법을 이용하면 축방향 수직 단면의 평균 두께 변화를 빠르게 확인할 수 있어 초음파 두께 측정 방식에 비해 신속한 감육 검사가 가능하다. 본 논문에서는 제안 기법의 원리를 설명하고, 2차원과 3차원 감육 배관 모델 및 시편을 이용한 전산 해석과 실험을 통해 제안한 기법의 적용성을 검증하였다.

• 한국공작기계학회논문집
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• 제12권1호
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• pp.8-15
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• 2003

The cylindrical object such as a water pipe or an oil pipeline are widely used in the infrastructure. Those pipes should be inspected periodically by human or a robot. However, since there is no edge or vertex in the pipe, it is very difficult for the robot to navigate along the pipe. In this paper in order to guide the robot along the axis of the pipe, an algorithm which find the axis using the measured range data from the robot to the pipe wall is developed The algorithm is verified using both the simulated range data and the measured one.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.99.1-99
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• 2002

In this paper, a computer-vision based pipe-inspection algorithm is developed. The algorithm uses the modified Hough transformation and a line-scanning approach to identify the edge line and radius of the pipe image, from which the eccentricity and dimension of the pipe-end is calculated. Line and circle detection was performed using Laplacian operator with input image which are acquired from the front and side cameras. In order to minimize the memory usage and the processing time, a clustering method with the modified Hough transformation for line detection. The dimension of inner and outer radius of pipe is calculated by proposed line-scanning method. The method scans several lines along t...

• Corrosion Science and Technology
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• 제11권6호
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• pp.225-231
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• 2012

Fitness-for-Service is a useful technology to determine replacement timing, next inspection timing or in-service when nuclear power plant's buried pipes are damaged. If is possible for buried pipes to be aged by material loss, cracks and occlusion as operating time goes by. Therefore Fitness-for-Service technology for buried pipe is useful for plant industry to perform replacement and repair. Fitness-for-Service for buried pipe is studied in terms of existing code and standard for Fitness-for-Service and a current developing code case. Fitness-for-Service for buried pipe was performed according to Code Case N-806 developed by ASME (American Society of Mechanical Engineers).

• 한국압력기기공학회 논문집
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• 제9권1호
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• pp.25-30
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• 2013

The periodic inspection of piping and pressure vessels welds in nuclear power plant has to provide reliable result related to weld flaws, such as location, maximum amplitude response, ultrasonic length, height and finally the nature or flaw pattern. The founded flaw in ultrasonic inspection is accepted or rejected based on these data. Specially, the amplitude of flaw response is used as basic parameter for flaw sizing and it may cause some deviation in length sizing result. Currently the ultrasonic inspections in nuclear power plant components are performed by specific inspection procedure which describing inspection technique include inspection system, calibration methodology and flaw characterizing. To perform ultrasonic inspection during in-service inspection, reference gain should be established before starting ultrasonic inspection by the requirement of ASME code. This reference gain used as basic criteria to evaluate flaw sizing. Sometimes, a little difference in establishing reference gain between calibration and field condition can lead to deviation in flaw sizing. Due to this difference, the inspection result may cause flaw sizing error. Therefore, the objective of this study is to compare and evaluate the ultrasonic amplitude difference between air filled and water filled pipe in nuclear power plant. Additionally, the accuracy of flaw sizing is estimated by comparing both conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.545-547
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• 2014

The portable vibration signal-based pipe wall thinning inspection device was developed in this work. Compared to wall-thinning detection using conventional ultrasonic thickness measurement gauge, the proposed device can estimate average wall thickness of wide range and be applied to in-service pipes. The measurement principle of the device was briefly described and the configrations of hardware and software were explained. It was shown that the device can gauge average wall-thickness of test specimens with high precision.

• 한국해양공학회지
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• 제20권2호
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• pp.8-15
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• 2006

Guided-waves-based mortar-filled steel pipe inspection is carried out through using EMAT (Electro magnetic acoustic transducer) and wavelet transform. Possibly existing anomalies such as separation (or void) and inclusion are made in the fabricated mortar-fled steel pipes: these anomalies are infected. Since guided waves have the long range inspection capability, EMAT has its own advantages over the conventional PZT (Piezoelectric zirconate titanate), and wavelet transform gives the multi-resolution on time-frequency domain results, the suggested technique gives an alternative way for inspecting mortar-filled steel pipes, which are popularly used for supporting marine structures such as piers, wharfs, moles, and dolphins. Through this study, it is show that the suggested technique is promising for detecting the amounts of separations and inclusions.

• 로봇학회논문지
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• 제17권2호
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• pp.159-163
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• 2022

A linearly moving structure in the area where the friction force is dominant - such as ducts filled with grease in the nuclear power plant - experiences increase in friction since the contact surface gets larger as the structure proceeds. To solve this problem is critical for the pipe inspection robot to investigate further area and this makes the system more energy-efficient. In this paper, we propose a passively growing sheath that can be added to linearly moving structures using zipper mechanism. The mechanism enables the linearly moving structures to maintain rolling contact condition against external environment, which provides substantial reduction in kinetic friction. To analyze the effect of the mechanism's head shape, we establish a physical model and compare to the experimental results. Finally, we have shown that the passively growing sheath can be successfully applied to the pipe inspection robot for the nuclear power plant.

• 비파괴검사학회지
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• 제29권2호
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• pp.145-152
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• 2009

국내 원전 가동중검사 기술은 대부분이 선진국에서 도입한 비파괴검사 장비를 진단현장에 적용하는 운영기술로 지금까지 선진 운영 기술의 습득에 중점을 두어, 검사 시스템 하드웨어 및 소프트웨어의 국내 제작 기술은 매우 미흡하였다. 때문에 국산 고유모델의 원전 가동중검사용 진단장치 개발의 필요성이 끊임없이 제기되었다. 본 연구에서는, 원전 배관 자동 초음파검사 시스템의 핵심 기술인 고성능 다채널 초음파 펄서/리시버와 A/D converter 보드, 디지털 제어보드를 개발하고 그 성능을 검증하였다. 검증 실험 결과는 개발된 시스템이 설계 목적에 부합하는 성능을 보이는 것으로 확인되었다.