• Tribology and Lubricants
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• 제26권1호
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• pp.73-77
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• 2010

One of the important trends for condition monitoring in the 21st century is the development of smart sensors that will permit the cost-effective continuous monitoring of key machine equipments. In this study, an integrated in-line oil monitoring sensor assigned for continuous in situ monitoring multiple parameters of oil performance is presented. The sensor estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical density of oil in three optical wave-bands ('Red', 'Green' and 'Blue') and water content is evaluated as relative saturation of oil by water. In order to evaluate the sensor's effectiveness, the sensor was applied to several used oil samples in steel making industry and the results were compared with those measured by standard test methods.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.518-525
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• 1996

본 고에서는 유리 집적광센서의 제작에 적합한 유리재료들의 종류와 특성을 설명하였으며, 이들 유리의 종류에 맞도록 개발되어진 제작기술 중에서 이온교환(Ion exchange)방법과 silica-on-silicon(SOS)방법을 소개하였다. 그리고 이러한 공정기술을 이용하여 제작되어진 유리 집적광센서 중에서 물체의 거리를 측정하기 위한 마이클슨 간섭계(michelson interferometer)와 물질의 농도를 측정하기 위한 화학센서(chemical sensor)들을 소개하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1388-1390
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• 1994

A polyimide-based capacitive humidity sensor has been designed and fabricated using silicon integrated-circuit technology, and its performance measured. The sensor showed excellent linearity, low temperature coefficient, and low hysteresis over a wide range of relative humidity and temperature. The signal conditioning circuits for detecting relative humidity and converting it to voltage have been developed based on a charge redistribution between capacitors using switched -capacitors.

• Smart Structures and Systems
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• 제12권1호
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• pp.23-39
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• 2013

In this article, a smart multifunctional optical system-on-a-chip (SOC) sensor platform is presented and its application for fiber Bragg grating (FBG) sensor interrogation in optical sensor networks is investigated. The smart SOC sensor platform consists of a superluminescent diode as a broadband source, a tunable microelectromechanical system (MEMS) based Fabry-P$\acute{e}$rot filter, photodetectors, and an integrated microcontroller for data acquisition, processing, and communication. Integrated with a wireless sensor network (WSN) module in a compact package, a smart optical sensor node is developed. The smart multifunctional sensor platform has the capability of interrogating different types of optical fiber sensors, including Fabry-P$\acute{e}$rot sensors and Bragg grating sensors. As a case study, the smart optical sensor platform is demonstrated to interrogate multiplexed FBG strain sensors. A time domain signal processing method is used to obtain the Bragg wavelength shift of two FBG strain sensors through sweeping the MEMS tunable Fabry-P$\acute{e}$rot filter. A tuning range of 46 nm and a tuning speed of 10 Hz are achieved. The smart optical sensor platform will open doors to many applications that require high performance optical WSNs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1679-1683
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• 2005

This paper suggests the new type of a joint torque sensor which is attached at each joint of a manipulator for making compliance. Previous six axis force/torque sensors are high cost and installed end-effector of the manipulator. However, torque on links of previous an end-effector cannot be measured. We design a joint torque sensor that can be fully integrated with an actuator in order to measure applying torque of the manipulator. The sensor system is designed through the structural analysis. The proposed joint torque sensors are installed to the 6 DOF manipulator of a mobile robot for hazardous works and we implemented experiments of measuring applied torque to the manipulator. By the experiment, we proved that the proposed low-cost joint torque sensor gives acceptable performance when we control a manipulator.

• International Journal of Aeronautical and Space Sciences
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• 제12권1호
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• pp.43-56
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• 2011

An integrated system composed of guidance, navigation and control (GNC) system for autonomous proximity operations and the docking of two spacecraft was developed. The position maneuvers were determined through the integration of the state-dependent Riccati equation formulated from nonlinear relative motion dynamics and relative navigation using rendezvous laser vision (Lidar) and a vision sensor system. In the vision sensor system, a switch between sensors was made along the approach phase in order to provide continuously effective navigation. As an extension of the rendezvous laser vision system, an automated terminal guidance scheme based on the Clohessy-Wiltshire state transition matrix was used to formulate a "V-bar hopping approach" reference trajectory. A proximity operations strategy was then adapted from the approach strategy used with the automated transfer vehicle. The attitude maneuvers, determined from a linear quadratic Gaussian-type control including quaternion based attitude estimation using star trackers or a vision sensor system, provided precise attitude control and robustness under uncertainties in the moments of inertia and external disturbances. These functions were then integrated into an autonomous GNC system that can perform proximity operations and meet all conditions for successful docking. A six-degree of freedom simulation was used to demonstrate the effectiveness of the integrated system.

• 한국정밀공학회지
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• 제27권11호
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• pp.30-36
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• 2010

Previous researches show that linearly integrated Hall sensor arrays (LIHaS) can detect cracks in the steel structure fast and effectively This paper proposes an algorithm that estimates the size and shape of cracks for the developed LIHaS. In most nondestructive testing (NDT), just crack existence and location are obtained by processing 1-dimensional data from the sensor that scans the object with relative speed in single direction. The proposed method is composed with two steps. The first step is constructing 2-dimensionally mapped data space by combining the converted position data from the time-based scan data with the position information of sensor arrays those are placed in the vertical direction to the scan direction. The second step is applying designed Laplacian filter and smoothing filter to estimate the size and shape of cracks. The experimental results of express train wheels show that the proposed algorithm is not only more reliable and accurate to detecting cracks but also effective to estimate the size and shape of cracks.

• 센서학회지
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• 제19권3호
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• pp.197-201
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• 2010

This paper describes the fabrication and characteristics of a NO sensor using ZnO thin film integrated 3C-SiC micro heater based on polycrystalline 3C-SiC thin film of operation in harsh environments. The sensitivity, response time, and operating properties in high temperature and voltages of NO sensors based SiC MEMS are measured and analyzed. The sensitivity of device with pure ZnO thin film at the heater operating power of 13.5 mW ($300^{\circ}C$) is 0.875 in NO gas concentration of 0.046 ppm. In the case of Pt doping, the sensitivity of at power consumption of 5.9 mW ($250^{\circ}C$) was 1.92 at same gas flow rate. The ZnO with doped Pt was showed higher sensitivity, lower working temperature and faster adsorption characteristics to NO gas than pure ZnO thin film. The NO gas sensor integrated SiC micro heater is more strength than others in high voltage and temperature environments.

• 한국광학회지
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• 제19권3호
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• pp.224-228
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• 2008

본 논문에서는 폴리머 마이크로링 공진기 기반의 고감도 집적광학형 온도센서를 제안하고 구현하였다. 이 센서는 열광학효과로 인한 공진기 소자의 공진파장의 이동으로부터 주변 온도 변화를 측정한다. 열팽창계수가 작은 실리콘 기판 위에 열광학계수가 큰 폴리머를 도입하여 공진기 센서를 제작함으로써 센서의 감도를 향상시켰다. 상온 부근 $20^{\circ}C{\sim}30^{\circ}C$의 범위에서 얻어진 온도센서의 감도는 약 -165 ${\pm}/^{\circ}C$였고, 온도분해능은 $0.1^{\circ}C$이하였다. 그리고 제작된 온도센서의 동작 특성은 표면에 놓여진 분석대상물의 굴절률 변화에 거의 영향을 받지 않음을 확인하였다. 따라서 제작된 센서는 다른 광센서에 집적되어 주변 온도 변화로 인하여 유발되는 오차를 효과적으로 보정할 수 있을 것으로 기대된다.

• 한국산학기술학회논문지
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• 제9권6호
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• pp.1619-1624
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• 2008

현재 유비쿼터스 서비스를 제공하기 위해 GPS(Global Positioning System), RFID(Radio Frequency IDentification) 및 센서 네트워크를 이용한 개별 미들웨어 및 인터페이스를 개발하고 있다. GPS는 주로 위치기반 서비스에, RFID를 식별을 통한 유통 물류 서비스에, 센서 노드는 온도, 습도, 기압 등의 상황 정보 수집에 응용되고 있다. 최근에 2 또는 3개의 이들 요소들이 농축산, 건설, 의료 등의 다양한 분야에 응용하면서 GPS, RFID 및 센서 노드를 통합하는 인터페이스 요구가 증가하고 있다. 이에 본 논문에서는 RFID, GPS, 센서 네트워크에서 수집된 상황데이터를 통합 처리하는 공통 인터페이스를 구현하고 실험을 통해 동작을 확인한다. 이 인터페이스는 필터링, 파싱, 인터페이스 관리, 큐잉, 하드웨어 및 미들웨어 접근 기능 등의 효율적인 데이터 처리 기능을 구현하고 동작을 검증한다. 그리고 GPS, RFID 및 센서 노드를 수집된 상황 데이터를 결합한 통합 프레임 구조를 제시하고, 복합형 유비쿼터스 응용 시스템에 제공되는 개방형 인터페이스를 제공하는 것을 확인한다. 이를 통하여 RFID, GPS, 센서 네트워크를 통해 얻어진 상황 데이터도 효과적으로 처리하여 다양한 유비쿼터스 응용 서비스에게 제공할 수 있을 것으로 사료된다.