• 한국건설관리학회논문집
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• 제24권4호
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• pp.52-59
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• 2023

현재 국내 건설현장에서 PC 부재의 평탄도 검사는 육안으로만 진행되고 있으며 PC 부재 제작 및 조립과 관련된 표준 시방서에 PC 부재의 평탄도 측정방법 및 허용오차에 대한 기준이 없는 실정이다. 따라서, PC 부재에 대한 적절한 평탄도 검사 방법 및 센싱 기반의 객관적인 측정 방법의 도입이 필요하다. 최근 건설산업에서 평탄도 측정과 관련하여 레이저 스캐너를 이용한 형상계측 연구가 활발하게 진행되고 있지만 정확도 외에 시간과 비용 측면에서는 고려하지 않아 현장 적용성을 판별하기 어렵다. 이 한계점을 해결하기 위한 본 연구의 두 가지 목적은 1) 플로어 프로파일러, 레이저 스캐너, 광파기를 이용해 PC 부재의 평탄도를 측정하고, 2) 플로어 프로파일러와 광파기와 레이저 스캐너를 비교하여 정확성, 시간 및 비용 측면에서 비교, 분석하여 스캐너 기술의 현장 적용성을 판단하는 것이다. 실험 결과, 레이저 스캐너는 높은 초기 투자 비용을 요구하지만, 계측 정확도가 0.64mm로 광파기의 2배 이상 우수한 것으로 나타났으며 플로어 프로파일러 및 광파기보다 효율적으로 PC 부재의 평탄도를 측정할 수 있었다. 따라서, 향후 건설산업에서 레이저 스캐너가 활용도가 더욱 높아질 것으로 기대한다.

• Smart Structures and Systems
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• 제18권3호
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• pp.601-623
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• 2016

Precast concrete elements are widely used in the construction of buildings and civil infrastructures as they provide higher construction quality and requires less construction time. However, any abnormalities in precast concrete surfaces such as non-flatness or distortion, can influence the erection of the elements as well as the functional performance of the connections between elements. Thus, it is important to undertake surface flatness and distortion inspection (SFDI) on precast concrete elements before their delivery to the construction sites. The traditional methods of SFDI which are conducted manually or by contact-type devices are, however, time-consuming, labor-intensive and error-prone. To tackle these problems, this study proposes techniques for SFDI of precast concrete elements using laser scanning technology. The proposed techniques estimate the $F_F$ number to evaluate the surface flatness, and estimate three different measurements, warping, bowing, and differential elevation between adjacent elements, to evaluate the surface distortion. The proposed techniques were validated by experiments on four small scale test specimens manufactured by a 3D printer. The measured surface flatness and distortion from the laser scanned data were compared to the actual ones, which were obtained from the designed surface geometries of the specimens. The validation experiments show that the proposed techniques can evaluate the surface flatness and distortion effectively and accurately. Furthermore, scanning experiments on two actual precast concrete bridge deck panels were conducted and the proposed techniques were successfully applied to the scanned data of the panels.

• 한국인터넷방송통신학회논문지
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• 제8권3호
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• pp.71-79
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• 2008

본 논문에서는 평판 디스플레이용 유리의 평탄 도와 두께를 측정하기 위한 검사시스템을 구성한다. 유리 계측에 필요한 레이저센서와 로봇 암의 성능을 분석 및 해석한다. 3가지 레이저 센서를 사용하여 비교 분석하였고, 로봇암은 볼 스크루 타입을 사용하여 유리 계측 방법을 논하고, 문제점을 찾아내어 해결책을 제시한다. 유리의 평탄도와 두께 측정에 있어 스테이지와 로봇암에 의한 오차를 최소화하기 위해서 기구적 오차를 고려한 계측을 통해 성능을 개선한다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.325-327
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• 2004

Novel surface profiler system for inspection of the display components is demonstrated In the case of the liquid crystal display, for example, not only the flatness of the alignment film but also the quality of rubbing can be inspected. Furthermore, the shape of the component such as the color filter, electrode and mirror can be inspected without removing each component.

• 한국기계가공학회지
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• 제20권2호
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• pp.101-106
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• 2021

In this paper, an inspection system has been developed where pneumatic instruments are used to stretch the film using compressed air, thus the curl problem can be overcome. When the pneumatic system is applied, a line scan camera should be used instead of an area camera because the COF surface makes an arc by the air pressure. The distance between the COF and the inspection camera should be kept constant to get a clear image, thus the position of COF is to be monitored on real-time. An operating software has been also developed which is switching on/off the pneumatic system, determining the COF position using a camera vision, displaying the contour of the COF side view, sending self-diagnosis result and etc. The developed system has been examined using the actual roll of COF, which convince that the system can be an effective device to inspect the COF rolls in process.

• 한국기계가공학회지
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• 제20권10호
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• pp.112-118
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• 2021

In this study, an inspection method using a color image is proposed to conduct a real-time inspection of covalent organic framework (COF) films to detect defects, if any. The COF film consists of an upper pattern SR and a lower PI. The proposed system detects the defects of more than 20 ㎛ on the SR surface owing to the characteristics of the pattern, whereas on the PI surface, it detects defects of more than 4 ㎛ by utilizing a micro-optical system. In the existing system, it is difficult for the operator to conduct a full inspection through a high-performance microscope. The proposed inspection algorithm performs the inspection by separating each color component using the color contrast of the pattern on the SR side, and on the PI surface it inspects the bonding state of the mounted chip. As a result, it is possible to confirm the exact location of the defects through the SR and PI surface inspections in the implemented inspection.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1079-1080
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• 2008

To improve productivity of TFT-LCD and PDP, it is required that the inspection system of flat glass should be established. It is composed of robot arms, base table, and laser sensors. This paper focuses on three non-contact laser sensors. After testing three laser sensors, LG-G30 is selected.

• 품질경영학회지
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• 제22권3호
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• pp.85-98
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• 1994

In current coordinate measuring machine practice, there are no commonly accepted sample sizes for estimating form errors which have a statistical confidence. Practically, sample size planning is important for the geometrical tolerance inspection using a coordinate measuring machine. We determine and validate appropriate sample sizes for form error estimation. Also, we develop form error estimation methods with certain confidence levels based on the obtained sample sizes in various form errors: straightness, flatness, circularity, and cylindericity.

• 산업경영시스템학회지
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• 제42권1호
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• pp.151-157
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• 2019

This study is about the process capability index (PCI). In this study, we introduce several indices including the index $C_{PR}$ and present the characteristics of the $C_{PR}$ as well as its validity. The difference between the other indices and the $C_{PR}$ is the way we use to estimate the standard deviation. Calculating the index, most indices use sample standard deviation while the index $C_{PR}$ uses range R. The sample standard deviation is generally a better estimator than the range R. But in the case of the panel process, the $C_{PR}$ has more consistency than the other indices at the point of non-conforming ratio which is an important term in quality control. The reason why the $C_{PR}$ using the range has better consistency is explained by introducing the concept of 'flatness ratio'. At least one million cells are present in one panel, so we can't inspect all of them. In estimating the PCI, it is necessary to consider the inspection cost together with the consistency. Even though we want smaller sample size at the point of inspection cost, the small sample size makes the PCI unreliable. There is 'trade off' between the inspection cost and the accuracy of the PCI. Therefore, we should obtain as large a sample size as possible under the allowed inspection cost. In order for $C_{PR}$ to be used throughout the industry, it is necessary to analyze the characteristics of the $C_{PR}$. Because the $C_{PR}$ is a kind of index including subgroup concept, the analysis should be done at the point of sample size of the subgroup. We present numerical analysis results of $C_{PR}$ by the data from the random number generating method. In this study, we also show the difference between the $C_{PR}$ using the range and the $C_P$ which is a representative index using the sample standard deviation. Regression analysis was used for the numerical analysis of the sample data. In addition, residual analysis and equal variance analysis was also conducted.