• Structural Monitoring and Maintenance
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• 제9권3호
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• pp.259-270
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• 2022

This study explores the use of the recently developed "strain-sensing smart skin" (S⁴) method for noncontact strain measurements on cement-based samples. S⁴ sensors are single-wall carbon nanotubes dilutely embedded in thin polymer films. Strains transmitted to the nanotubes cause systematic shifts in their near-infrared fluorescence spectra, which are analyzed to deduce local strain values. It is found that with cement-based materials, this method is hampered by spectral interference from structured near-infrared cement luminescence. However, application of an opaque blocking layer between the specimen surface and the nanotube sensing film enables interference-free strain measurements. Tests were performed on cement, mortar, and concrete specimens with such modified S⁴ coatings. When specimens were subjected to uniaxial compressive stress, the spectral peak separations varied linearly and predictably with induced strain. These results demonstrate that S⁴ is a promising emerging technology for measuring strains down to ca. 30 𝜇𝜀 in concrete structures.

• ETRI Journal
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• 제36권3호
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• pp.361-366
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• 2014

In this paper, a new, simple capacitive tilt sensor with a metallic ball is proposed. The proposed tilt sensor has only two electrodes and a metallic ball, and this design assists in managing the inherent contact problem in measuring tilt angles. Capacitive sensing, compared with other types of tilt sensor, has many advantages such as simplicity, noncontact measurement, long-throw linear displacement, and sub-micron plate spacing. Its design and fabrication process are significantly simpler than previous types of tilt sensors. The dimensions of the prototype tilt sensor are $20mm{\times}20mm$, and the diameter of the polystyrene tube is 5 mm with a tube thickness of 0.15 mm. An analytical study of the prototype capacitive tilt sensor was undertaken, and the experimental results demonstrate the relationship between the tilt angles and measured capacitances compared with the analytical study.

• 한국수소및신에너지학회논문집
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• 제25권5호
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• pp.525-532
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• 2014

The sensing of a stack coolant deficiency is very important in that cooling performance of a fuel cell, overheating prevention of a stack or coolant heater. This paper explains the performance comparison between the coolant contact/noncontact level sensors and coolant deficiency sensing logic using the pressure sensor in a stagnant or circulating flow. Throughout the comparison, the pressure sensor is more suitable than the other sensors in terms of the precision, fast response, sensing frequency. After the experiment, the pressure sensor is equipped to an FCEV(Fuel Cell Electric Vehicle) to verify sensing definitely. There was no miss-sensing using pressure sensor while FCEV runs in the conditions of the paved road and cross country road.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.143-146
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• 2006

In this paper, a hybrid sensor is proposed that has two capabilities: The first is to sense longitudinal of flexural elastic waves selectively which are transmitted along the targe shaft, the second to measure the rotating speed of the shaft. All measurement are made in a noncontact manner since this sensor uses magnetostriction as its measuring principles. Furthermore, the switching between these two sensing capabilities are accomplished by a very simple mechanical operation. To verify the capabilities of the Proposed sensor, an Prototype sensor are fabricated and the experiments are made. The result shows this sensor can embody two sensing capabilities in one sensor configuration.

• 한국광학회지
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• 제14권3호
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• pp.260-265
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• 2003

미세하게 진동하는 물체의 변위를 비접촉식으로 측정할 수 있는 광학계를 설계하고 제작하였다. 도플러효과에 의한 방법과는 달리, 하나의 볼록렌즈를 이용하여 물체 표면에 비스듬하게 입사하여 물체 표면에서 반사되는 광점의 위치 변화를 PSD(position-sensitive detector)로 검출하였다. 이러한 방법으로 전체적인 장비의 크기를 작게 하였고 빠른 응답 속도를 구현하였다. 본 장비는 $\pm$1.0 $\mu\textrm{m}$의 분해능을 나타내었으며, 스피커의 진동 실험 및 CD-ROM안에서 회전하는 C교의 진동을 측정하였다.

• Current Optics and Photonics
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• 제7권1호
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• pp.38-46
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• 2023

Optical Fourier-domain reflectometry (OFDR) sensors have been widely used to measure distances with high resolution and speed in a noncontact state. In the electroplating process of a printed circuit board, it is critically important to monitor the copper-plating thickness, as small deviations can lead to defects, such as an open or short circuit. In this paper we employ a phase-based OFDR sensor for in situ relative distance sensing of a sample with nanometer-scale resolution, during electroplating. We also develop an optical-path difference (OPD)-regulated sensing probe that can maintain a preset distance from the sample. This function can markedly facilitate practical measurements in two aspects: Optimal distance setting for high signal-to-noise ratio OFDR sensing, and protection of a fragile probe tip via vertical evasion movement. In a sample with a centimeter-scale structure, a conventional OFDR sensor will probably either bump into the sample or practically out of the detection range of the sensing probe. To address this limitation, a novel OPD-regulated OFDR system is designed by combining the OFDR sensing probe and linear piezo motors with feedback-loop control. By using multiple OFDR sensors, it is possible to effectively monitor copper-plating thickness in situ and uniformize it at various positions.

• 한국전산구조공학회논문집
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• 제29권6호
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• pp.513-519
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• 2016

본 논문에서는 기존 파고 측정 센서의 한계를 극복하기 위하여 레이저 장비 중 LDV를 이용하여 동조액체기둥감쇠기 안의 액체의 파고를 측정하는 방법을 제안하고 검증하였다. 비접촉 센서의 장점과 LDV가 속도와 변위를 측정하는 원리를 기술하였고 대상 물체가 액체인 경우에 요구되는 사항들에 대하여 실험적으로 파악하였다. 투명한 액체는 레이저 광선을 대부분 투과시켜 LDV에 되돌아오는 광량이 부족해 측정이 불가능함을 확인하였고 이를 증가시키기 위해 염료를 혼합하였다. 이때, 염료의 색에 따라 광량에 차이가 발생함을 확인하여 LDV에 사용된 레이저 광선의 파장과 연관된 결과를 도출하였다. 염료를 혼합한 후 광량이 충분한 경우에도 발생하는 데이터의 오차를 제거하기 위해 염료의 농도를 변화시키며 그에 따른 데이터의 정확도를 파악하였다. 결과적으로 모든 가시광선의 빛을 반사시키는 흰색의 염료를 충분한 농도로 혼합하였을 때 LDV를 이용한 TLCD의 파고 측정의 실험적인 결과가 용량식 파고계와 일치함을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.407-410
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• 1995

Many researches on measurement technology has been made and developed by various methods. Considering the measurement environment with cutting fluid, coolant and the like, contact type measurement methods are mostly used. But contact measurement method has measuring force and so the sensing head becomes worn. By these reasons, we considered sensors not influenced by the former fluid and so can acquire accrate measured values using error compensation due to temperature and vibration. For this purpose, eddy current sensors and Extended kalman Filter Algorithm for processing measured data has been used. In this paper, we present new technology that can be used for measuring workpiece with previous bad environment using direct method and comparison measurement method. We used cylindrical workpieces which were produced by grinding machine for the target.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.62-67
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• 2009

기존의 증강현실 기반 상호작용 기법은 상호작용 주체의 원활한 추적을 위해 마커 기반의 패들이나 데이터 글러브 등의 부가적인 입력장치에 의존하거나 제한적인 3차원 입력만을 허용하는 경우가 많았다. 본 논문에서는 대상 개체 주변 공간의 물리적 점유를 감지하여 사용자의 입력을 해석하는 비접촉식 수동형 공간 상호작용 기법을 제안한다. 제안된 방법은 깊이 카메라로 구성한 증강현실 환경에 가상의 공간 센서를 배치하여 사용자의 입력을 공간적으로 해석한다. 그 결과, 부가적인 입력장치의 착용이 필요하지 않으며, 입력 형태에 대한 제약을 최소화하고, 증강된 영상 내의 상호작용 객체 간에 정확한 거리감을 제시한다. 향후 이러한 기법은 미니어쳐 AR 시스템과 같은 동적 콘텐츠 전시 플랫폼의 인터페이스에 적용될 것으로 기대된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.409-412
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• 1996

Ultrasonic sensors are widely used in various applications due to advantages of low cost, simplicity in construction, mechanical robustness, and little environmental restriction in usage. But the main purposes of the noncontact sensing are rather narrowly confined within object detection and distance measurement. For the application of object recognition, ultrasonic sensors exhibit several shortcomings of poor directionality which results in low spatial resolution of objects, and specularity which gives frequent erroneous range readings. To resolve these problems in object recognition, an array of the sensor has been used. To improve the spatial resolution, more number of sensors are used in essence throughout the various devices of the sensor arrays. Under the disguise of a fixed number of the sensors, the array can be shifted mechanically in several steps. In this paper we propose a practical sensor resolution enhancement method using an electronic circuit accompanying the sensor array. The circuit changes the transmitter output voltage in several steps. Using the known sensor characteristics, a set of different return echo signals provide enhanced spatial resolution. The improvement is obtained with neither the cost of the increased number of the sensors nor extra mechanical devices.