Soft Computing을 이용한 배열 센서 시스템의 제어 성능 개선

나승유,안명국 한국센서학회 2003 센서학회지 Vol.12 No.2

In this paper, we propose a method to obtain a linear characteristic using soft computing for systems which have array sensors of nonlinear characteristics. Also a procedure utilizing the pattern information of array sensors without additional sensors is proposed to reduce disturbance effects. For a typical example, even a single CdS cell for CdS array has nonlinear characteristics. Overall linear characteristic for CdS array is obtained using fuzzy logic for each cell and overlapped portion. In addition, further improvement for linearization is obtained applying genetic algorithms for the parameters of membership functions. Also the effect of disturbing external light changes to the CdS array can be reduced without using any additional sensors for calibration. The proposed method based on fuzzy logic shows improvements for position measurements and disturbance reduction to external light changes due to the fuzziness of the shadow boundary as well as the inherent nonlinearity of the CdS array. This improvement is shown by applying the proposed method to the ball position measurements of a magnetic levitation system. 본 논문에서는 비선형 특성을 갖는 센서 배열을 사용하는 시스템에서, 센서 배열에 soft computing을 이용하여 선형적인 특성을 얻고, 배열의 특성을 이용하여 외란의 영향을 감소시켜 시스템의 성능을 향상시키는 방법을 제안한다. 대표적인 예로 배열에 사용된 광전도 센서인 CdS는 단일 CdS 셀조차도 비선형적인 특성을 갖고 있기 때문에 비선형 특성을 소속 함수로 표현하는 퍼지 변수를 사용한다. 배열로 사용되는 센서에 각 단일 센서의 소속 함수와 특성을 이용하는 퍼지 논리를 적용하여 전체적으로 선형화된 센서 특성을 얻는다. 각 센서의 비선형적 요소를 표현하는 소속 함수의 파라미터들에 유전 알고리즘을 사용하여 최적화된 선형 특성을 얻어 시스템의 성능을 향상 시킬 수 있다. 또한 보정을 위한 센서를 추가하지 않고 센서 배열의 특성을 이용하여 광전도 센서가 민감한 영향을 받는 외란을 보정하여 시스템의 외란 제거 성능을 향상 시킬 수 있다. CdS 센서 배열의 자체 비선형성 뿐만 아니라 입력되는 물체의 그림자는 경계가 뚜렷하지 않고 흐릿하므로 퍼지 논리를 이용하는 방법이 거리측정과 외부 광원에 의한 외란에 대해 향상된 결과를 보인다. 제안된 방법을 적용한 센서 배열을 자기부상(Magnetic Levitation System)에서 볼의 거리 측정에 적용하여 성능을 검증한다.

나노 재료를 이용한 최신 센서 기술 동향-리뷰

박준식,박광범,김성동,박효덕 한국센서학회 2009 센서학회지 Vol.18 No.5

최근 인류의 삶의 질 향상에 따라 건강하고, 쾌적하고, 편안한 삶을 살기 위한 많은 노력이 진행되고 있다. 센서는 이러한 삶의 질 향상을 위해서 필수불가결한 요소 중 하나이며, 고성능의 지능화된 센서가 요구되고 있어, 앞으로 이에 대한 수요는 더욱 증대될 것으로 생각된다. 최근의 센서 연구 개발 방향은 센서에 기능을 부여하는 기능성 재료가 중요한 요소로 더욱 부각되고 있으며, 특히, 다양한 성분과 형태로 존재하는 나노 기능 재료는 기존의 벌크 재료와는 차별화된 독특한 물리, 화학, 기계, 광학적 특성을 갖고 있어 더욱 주목받고 있다. 최근 기존의 나노 입자 연구에서 더욱 발전하여 센서로 적용하기 위한 나노선이나 CNT를 포함한 나노튜브, 나노 복합재료 등의 연구가 매우 활발하다. 본 논문에서는 이러한 나노 재료를 이용한 가스 센서, 수질 센서, 바이오 센서, 광 센서 그리고 물리 센서 등 최신 나노 센서 연구개발 동향을 살펴보았으며, 미래 센서기술 발전방향 중 하나로서 나노 재료에 의한 센서의 고기능화 및 극소형화가 매우 중요한 부분으로 활용될 것으로 예측되었다.

보상용 적외선 센서를 사용한 비분산 적외선 이산화탄소 센서의 온도특성

이승환 한국센서학회 2016 센서학회지 Vol.25 No.2

NDIR CO2 gas sensor was built with ASIC implemented thermopile sensor which included temperature sensor and unique elliptical waveguide structures in this paper. The temperature dependency of dual infrared sensor module (CO2 and reference IR sensors) has been characterized and its output voltage characteristics according to the temperature and gas concentration were proposed for the first time. NDIR CO2 gas and reference IR sensors showed linear output voltages according to the variation of ambient temperatures from 243 K to 333 K and their slopes were 14.2 mV/K and 8.8 mV/K, respectively. The output voltages of temperature sensor also presented a linear dependency according to the ambient temperature and could be described with . The output voltage ratio between CO2 and reference IR sensors revealed irrelevant to the changes of ambient temperatures and gave a constant value around 1.6255 with standard deviation 0.008 at 0 ppm. The output voltage of CO2 gas sensor at zero ppm CO2 gas consisted of two components; one is caused by the HPB (half pass-band) of IR filter and the other is attributed to the part of CO2 absorption wavelength. The characteristics of output voltages of CO2 gas sensor could be accurately modeled with three parameters which are dependent upon the ambient temperatures and represented small average error less than 1.5% with 5% standard deviation.

맥 센서 어레이(array)의 실리콘(silicone) 코팅 두께에 따른 센서 간 간섭효과

김영민,전민호,전영주 한국센서학회 2016 센서학회지 Vol.25 No.1

Pulse diagnosis is one of the representative diagnostic methods in Oriental medicine. In this study, a pulse pressure sensor array coated with silicone, which includes 6 piezo-resistive sensors and 1 thermistor, is fabricated for pulse measurement. It is necessary to coat the pulse sensor array with silicone to avoid the fracture or damage of pressure sensors when the sensor is in contact with the skin and a constant pressure is applied. However, the silicone coating on the pulse sensor array can cause signal interference among the sensors in the pulse sensor array. The interference number (IN), a calculation for expressing the degree of interference among channels, is changed according to the silicone thickness on the pulse sensor array. The IN is increased by a thick silicone coating, but the fabrication error, an important index for the mass production of the sensor array, is reduced by the thickness of the silicone coating. We propose that the thickness of the silicone on the pulse sensor array is an important consideration for the performance of the fabricated sensor and manufacturing repeatability.

상지재활로봇의 팔힘측정용 2축 힘센서 설계

김갑순 한국센서학회 2015 센서학회지 Vol.24 No.2

This paper describes the design of a two-axis force sensor with two step plate beams for measuring forces in an upper-limb rehabilitationrobot. The two-axis force sensor is composed of a Fz force sensor and a Ty torque sensor. The Fz force sensor measures theforce applied to a patient’s arm pushed by a rehabilitation robot and the force of patient's arm. The Ty torque sensor measures the torquegenerated by a patient’s arm motion in an emergency. The structure of sensor is composed of a force transmitting block, two step platebeams and two fixture blocks. The two-axis force sensor was designed using FEM (Finite Element Method), and manufactured usingstrain-gages. The characteristics test of the two-axis force sensor was carried out. as a test results, the interference error of the two-axisforce sensor was less than 1.24%, the repeatability error of each sensor was less than 0.03%, and the non-linearity was less than 0.02%.

손목 피부 온도에 의한 맥센서 어레이(array)의 신호 변동 및 보정

전민호,전영주,김영민 한국센서학회 2017 센서학회지 Vol.26 No.2

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperaturesensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuringpulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at 35°C (the maximum wrist temperature), thedevice was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sen-sor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during tem- perature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect tothickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the com-pensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

닌히드린 용액의 저온 건조에 의한 프롤린 검출을 위한종이기반 센서의 분해능 개선

김지관,최영수 한국센서학회 2022 센서학회지 Vol.31 No.6

In this study, we describe the improvement of the resolution of a paper-based sensor by fabricating a high-concentration ninhydrin part using a low-temperature drying method to detect proline with high resolution. In the conventional paper-based sensor for detecting proline, the ninhydrin part is fabricated at room temperature, and in this process, the ninhydrin solution spreads around the ninhydrin part. Therefore, the concentration of the ninhydrin part becomes lower than that of the applied solution, lowering the resolution of the sensor. The proposed paper-based sensor better improved the sensitivity of the sensor compared to the existing sensor by fabricating a high-concentration ninhydrin part through drying the ninhydrin solution using a low-temperature drying method. Owing to the experiment, the intensity of the green color of the paper-based sensor with the integrated ninhydrin part fabricated at 10℃ is approximately 20% lower than the paper-based sensor with an integrated ninhydrin part fabricated at room temperature, indicating better sensor resolution. Therefore, the paper-based sensor with an integrated ninhydrin part fabricated at a high concentration could be useful for diagnosing drought.

단일전극을 가진 마이크로 가스센서의 제작 및 특성

송갑득,방영일,이상문,이윤수,최낙진,주병수,서무교,허증수,이덕동 한국센서학회 2002 센서학회지 Vol.11 No.6

Micro gas sensor with single electrode was proposed for improving stability and sensitivity. Generally, metal oxide gas sensors have two electrodes for heating and sensing. This fabricated new type sensor have only a single electrode by forming a sensing material onto heating electrode. Pt as a heating and sensing electrode was sputtered on glass substrate and a SnO2 sensing material was thermally evaporated on Pt electrode. SnO2 was patterned by lift-off process and then thermally oxidized in O2 condition for 1 hr., 600 ℃. The size of fabricated sensor was 1.9 × 2.1 mm2. As a result of CO gas sensing characteristics, this sensor showed 100 mV change for 1,000 ppm and linearity for wide range(0 ∼ 10,000 ppm) of gas concentrations. And the sensor shows a good recovery characteristics of 1 % deviation compared to initial resistance. 센서의 안정도와 감도를 개선시킬 수 있는 단일전극을 가진 열선형 마이크로 가스센서를 제작하였다. 일반적으로, 금속산화물 반도체를 이용한 가스센서는 히터전극과 감지전극의 두 개의 전극을 가지고 있다. 제작된 센서는 히터전극위에 감지물질을 형성하여 단일 전극을 가지는 구조를 가지고 있다. 히터와 감지전극으로 사용되는 Pt는 glass 기판위에 스퍼터링법으로 형성하였으며, SnO2 감지물질은 제작된 Pt 전극위에 열증착시켜 형성하였다. SnO2 막은 lift-off 공정을 이용해서 패턴을 형성하고 1시간 동안 산소분위기에서 열산화하였다. 제작된 소자의 크기는 1.9×2.1 mm2 이다. CO 가스에 대한 감지특성을 조사한 결과 1,000 ppm에 대해 100 mV의 출력변화를 나타내었으며, 넓은 농도범위(0 ∼ 10,000 ppm)에서 선형적인 전압출력을 나타내었다. 또한 가스 반응 전과 반응 후의 전압출력을 비교해 볼 때, 1 % 이내의 편차를 나타내는 우수한 회복성을 나타내었다.

차량용 통합 센서 모듈 제어를 위한 시뮬레이터 개발

전진영,변형기,박정연 한국센서학회 2013 센서학회지 Vol.22 No.1

The integrated sensor module of vehicle combines the functions of rain sensor, auto defog sensor, and sun angle sensor into a single module. These functions originally were applied to work separatively. This integrated sensor module should meet the each performance which appears from the individual modules up to the same level or higher. Therefore, it is important to verify the stability and the accuracy considering the characteristics of the integrated sensor module according to various situations. For the verification, we need to use the actual data of integrated sensor module measured but, a lot of time and money is needed to collect data measured under various circumstances when operating. Thus, through the development of this simulator for the control of the integrated sensor module, we can use it effectively for the initial verification of integrated sensor module by implementing the various situations. In this paper, the simulator for controlling the integrated sensor module which combines vision-based rain sensor, auto defog sensor, auto light sensor, and sun angle sensor has been developed.

손가락 힘측정장치의 3축 힘센서 설계

이경준,김갑순 한국센서학회 2016 센서학회지 Vol.25 No.2

This paper describes the design and fabrication of a three-axis force sensor with three parallel plate structures(PPSs) for measuring force in a finger force measuring system for a spherical object catch. The three-axis force sensor is composed of a Fx force sensor, Fy force sensor and a Fz force sensor, and the elements of Fx force sensor and Fy force sensor are a parallel plate structure(PPS) respectively and Fz force sensor is two PPS. The three-axis force sensor was designed using FEM(Finite Element Method), and manufactured using strain-gages. The characteristics test of the three-axis force sensor was carried out. As a test results, the interference error of the three-axis force sensor was less than 1.32%, the repeatability error of each sensor was less than 0.04%, and the non-linearity was less than 0.04%.