• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.156-156
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• 2017

Most crop damages have been occurred by vermin(e.g., wild birds and herbivores) during the period between seeding and the cotyledon level. In this study, to minimize the damage by vermin and acquire the benefits such as protection against weeds and maintenance of water content in soil, immediately vinyl mulching after seeding was devised. Vinyl mulching has been generally covered with black color vinyl, that crop seeding locations cannot be detected by visible light range. Before punching vinyl, non-contact and non-destructive methods that can continuously determine the locations are necessary. In this study, a crop position detection method was studied that uses infrared thermal image sensor to determine the cotyledon position under vinyl mulch. The moving system for acquiring image arrays has been developed for continuously detecting crop locations under plastic mulching on the field. A sliding mechanical device was developed to move the sensor, which were arranged in the form of a linear array, perpendicular to the array using a micro-controller integrated with a stepping motor. The experiments were conducted while moving 4.00 cm/s speed of the IR sensor by the rotational speed of the stepping motor based on a digital pulse width modulation signal from the micro-controller. The acquired images were calibrated with the spatial image correlation. The collected data were processed using moving averaging on interpolation to determine the frame where the variance was the smallest in resolution units of 1.02 cm. For this study, the spline method was relatively faster than the other polynomial interpolation methods, because it has a lower maximum order of formulation when using a system such as the tridiagonal linear equation system which provided the capability of real-time processing. The temperature distribution corresponding to the distance between the crops was 10 cm, and the more clearly the leaf pattern of the crop was visually confirmed. The frequency difference was decreased, as the number of overlapped pixels was increased. Also the wave pattern of points where the crops were recognized were reduced.

• 한국융합학회논문지
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• 제8권11호
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• pp.49-56
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• 2017

컬링 스위핑 동작은 컬링 스톤의 위치를 조절하는 중요한 동작 중 하나이며, 스위핑 속도와 브룸 패드에 가해지는 힘이 중요한 연구 대상이다. 본 연구에서는 컬링 스위핑 동작에서 컬링 브룸 패드에 가해지는 힘을 측정할 수 있는 장비를 개발하였으며, 두 개의 로드셀을 브룸 패드와 패드 홀더 사이에 장착하는 구조를 이용하였다. 로드셀에서 발생되는 아날로그 신호는 마이크로 제어기를 이용하여 초당 약 300회의 속도로 샘플링을 수행한 후 10 bit 디지털 신호로 변환하였다. 3개의 M1 급 분동을 이용하여 로드셀의 교정과 측정된 전기 신호를 질량(힘)으로 환산하는 회귀 방정식을 추출하였으며, 브룸의 무게 증가를 최소화하기 위해서 웨어러블 장비로 구성하였다. 스포츠 분야에서 힘 측정 시 기준 장비로 사용하는 지면 반력기와 개발된 장비에 동일한 힘을 가하면서 측정된 측정값 차이는 약 $0.909{\pm}1.375N$ (평균과 표준 편차)로 측정되었다. 개발된 장비는 스위핑 동작과 유사한 힘 측정을 필요로 하는 다른 종류의 연구에도 적용이 가능할 것으로 판단된다.

• 센서학회지
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• 제12권1호
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• pp.24-33
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• 2003

This research is about a comfort sensing system for human environmental monitoring using a one-bodied humidity and temperature sensor and an air flow sensor. The thermal comfort that a human being feels in indoor environment has been known to be influenced mostly by six parameters, i.e. air temperature, radiation, air flow, humidity, activity level and clothing thermal resistance. Considering an environmental monitoring, we have designed and fabricated a one-bodied humidity and temperature sensor and an air flow sensor that detect air relative humidity, temperature and air flow in human environment using surface micromachining technologies. Micro-controller calculates a PMV (predicted mean vote) and CSV (comfort sensing vote) with sensing signals and display a PMV on LCD (liquid crystal display) for human comfort on indoor climate. Our work has demonstrated that a comfort sensing system can provide an effective means of measuring and monitoring the indoor comfort sensing index of a human being. Experimental results with simulated environment clearly suggest that our comfort sensing system can be used in many applications such as air conditioning system, feedback controlling in automobile, home and hospital etc..

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.702-712
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• 2016

A wrist watch type wearable cardiovascular monitoring device is proposed for continuous and convenient monitoring of the patient's cardiovascular system. For comprehensive monitoring of the patient's cardiovascular system, the concurrent electrocardiogram (ECG) and arterial pulse wave (APW) sensor front-end are fabricated in $0.18{\mu}m$ CMOS technology. The ECG sensor frontend achieves 84.6-dB CMRR and $2.3-{\mu}Vrms$-input referred noise with $30-{\mu}W$ power consumption. The APW sensor front-end achieves $3.2-V/{\Omega}$ sensitivity with accurate bio-impedance measurement lesser than 1% error, consuming only $984-{\mu}W$. The ECG and APW sensor front-end is combined with power management unit, micro controller unit (MCU), display and Bluetooth transceiver so that concurrently measured ECG and APW can be transmitted into smartphone, showing patient's cardiovascular state in real time. In order to verify operation of the cardiovascular monitoring system, cardiovascular indicator is extracted from the healthy volunteer. As a result, 5.74 m/second-pulse wave velocity (PWV), 79.1 beats/minute-heart rate (HR) and positive slope of b-d peak-accelerated arterial pulse wave (AAPW) are achieved, showing the volunteer's healthy cardiovascular state.

• 전력전자학회논문지
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• 제10권3호
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• pp.211-218
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• 2005

SRM은 간단하면서 견고한 전동기 구조. 넓은 속도범위에 걸쳐 고효율, 탁월한 제어성능 등을 가지고 있다. 그러나 SRM의 전원부에는 일반적으로 다이오드 정류기를 사용하고 정류기의 출력단에 평활용 커패시터를 사용한다. 따라서 입력전류 파형은 폭이 좁은 펄스형태의 전류를 발생하게 되며 많은 고조파의 성분을 포함하여 제어시스템의 오동작을 발생하게 되는 원인이 된다. 본 논문에서는 energy-efficient C-dump 컨버터의 입력 전원부에 승압형 컨버터를 연결하여 고조파 성분을 저감하여 역률을 개선하는 구동시스템에 관하여 연구하였다. SRM제어를 위해 저 가격의 원칩 80C196KC와 각도제어를 위해 EPROM을 이용하였다. 시뮬레이션과 실험을 통하여 제안된 시스템의 역률 개선을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제17권9호
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• pp.1268-1275
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• 2003

In this paper, a compact 3-DOF mobile microrobot with sub-micron resolution is presented. It has many outstanding features : it is as small as a coin ; its precision is of sub-micrometer resolution on the plane ; it has an unlimited travel range ; and it has simple and compact mechanisms and structures which can be realized at low cost. With the impact actuating mechanism, this system enable both fast coarse motion and highly precise fine motion with a pulse wave input voltage controlled. The 1 -DOF impact actuating mechanism is modeled by taking into consideration the friction between the piezoelectric actuator and base. This modeling technique is extended to simulate the motion of the 3-DOF mobile robot. In addition, experiments are conducted to verify that the simulations accurately represent the real system. The modeling and simulation results will be used to design the model-based controller for the target system. The developed system can be used as a robotic positioning device in the micromanipulation system that determines the position of micro-sized components or particles in a small space, or assemble them in the meso-scale structure.

• 한국전기전자재료학회논문지
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• 제32권3호
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• pp.256-261
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• 2019

The use of military lithium batteries in this field accelerates the generation of internal pressure because the active materials, lithium and the electrolyte, react to form sulfur dioxide gas. This also reduces the amount of electrolyte. In this condition, batteries can 'vent' or 'explode' especially when completely discharged. Such venting and explosion can be regarded as a safety accident, as toxic gases and shrapnel are ejected from the batteries which can harm the user. A DTaQ was carried out in 2017 as a quality problem solution project to solve this safety issue. A protection circuit was thereby developed, which included a micro controller unit (MCU) which can stop battery usage when in an over-discharging state by sensing its low-voltage condition. In 2018, this concept was expanded to lithium batteries for the remote controlled ammunition system. This paper reports results of the improved performance.

• 한국기계가공학회지
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• 제19권10호
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• pp.1-7
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• 2020

In this study, a multichannel gas-liquid microextraction system is designed by integrating the automatic elution of extraction line and multichannel gas-purging liquid phase microextraction. The system uses an injection pump and inert gas to push the extraction solvent to a sample bottle of a gas-phase color autosampler and then implements multichannel gas-liquid microextraction and gas chromatography-mass spectrometry. The system also employs a three-way integrated micro-high-temperature heater, syringe pump, and microflow controller to realize the simultaneous processing of multiple groups of samples, thus improving the sample pretreatment speed and reproducibility and reducing human error. Autoinjection experiments were implemented with polycyclic aromatic hydrocarbon standard samples. The experiments show that the average recovery rate of the system exceeds 70%, and the relative standard among the channels is less than 15%.

• 전기전자학회논문지
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• 제25권2호
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• pp.330-336
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• 2021

하드웨어 이중화 구성 수를 줄이는 대표적인 방법은 마이크로컨트롤러로 고장을 검출, 식별 및 수용을 위한 해석적 기법으로 구현하는 것이다. 본 논문에서는 해석적 기법 중 하나인 고장 검출 필터를 항공기 터보팬 엔진 시스템에 적용하였다. 고장 검출 필터는 특수한 형태의 관측기로써 특정한 고장 발생시 잔차가 출력 공간에서 일정한 방향을 유지함으로써 고장의 위치 판별이 가능한 장점이 있다. 이에 본 논문에서는 터보팬 엔진 내 공기 터빈 시스템의 단일 입출력 동적 시스템 모델링, 고장 검출 필터 설계 및 이를 적용한 모의실험 결과를 나타내었다. 모의실험 결과를 통해 고장 검출 필터가 갖는 방향성에 대한 민감성 효과로 고장 검출이 유효하게 적용될 수 있음을 보였다.

• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.103-112
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• 2020

Field robots are used in various fields, such as agriculture, forestry, manufacturing, and construction; their use has recently expanded to include submarine areas. Field robots can aid in various tasks, such as soil transport, ground clearance, and dismantling of buildings. As field robots are used in a variety of different areas, the difficulty of the work is also quite varied. Increased difficulty is associated with an increased risk of accidents involving the field robot. In order to reduce the accident rate of field robot workers, the need for digitalization and automation of field robots is becoming more of an issue. To this end, it is necessary to study a system that enables workers to do their work without directly contacting a field robot. Therefore, in this paper, we introduce a control system for wireless remote control of a small field robot. The field robot can be wirelessly controlled by a worker in a remote location if the worker cannot be present at the work site. The implemented remote system is tested according to the type of work, and the operating characteristics of the remote system are assessed.