• 한국초전도ㆍ저온공학회논문지
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• 제12권2호
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• pp.17-20
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• 2010

A considerable amount of research material discussing designs and properties of High Temperature Superconducting Fault Current Limiter (HTS FCL) is available. However, a shortage of research concerning positioning of HTS FCL in power grid is felt. In this paper a feasibility study of HTS FCL positioning in Smart Grid through simulation analysis is carried out. A complete power network (including generation, transmission and distribution) is modeled in Simulink / SimPowerSystems. A generalized HTS FCL is also designed by integrating Simulink and SimPowerSystem blocks. The distribution network of the model has a wind turbine attached to it forming a micro grid. Three phase fault have been simulated along with placing FCL models at key points of the distribution grid. It is observed that distribution grid, having distributed generation sources attached to it, must not have a single FCL located at the substation level. Optimized HTS FCL location regarding the best fault current contribution from wind turbine has been determined through simulation analysis.

• 한국정밀공학회지
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• 제27권1호
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• pp.125-133
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• 2010

A versatile micro-robotic platform for micro/nano scale assembly has been demanded in a variety of application areas such as micro-biology and nanotechnology. In the near future, a flexible and compact platform could be effectively used in a scanning electron microscope chamber. We are developing a platform that consists of miniature mobile robots and a compact positioning stage with multi degree-of-freedom. This paper presents the design and the implementation of a low-cost and compact multi degree of freedom position sensor that is capable of measuring absolute translational and rotational displacement. The proposed sensor is implemented by using a CMOS type image sensor and a target with specific hole patterns. Experimental design based on statistics was applied to finding optimal design of the target. Efficient algorithms for image processing and absolute position decoding are discussed. Simple calibration to eliminate the influence of inaccuracy of the fabricated target on the measuring performance also presented. The developed sensor was characterized by using a laser interferometer. It can be concluded that the sensor system has submicron resolution and accuracy of ${\pm}4{\mu}m$ over full travel range. The proposed vision-based sensor is cost-effective and used as a compact feedback device for implementation of a micro robotic platform.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.42-45
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• 1998

In this paper, a fuzzy control technique using adjustable scale factors and Lyapunov Function for the precise position control of DC servo system is introduced. The suitable scale factors were selected and the stable control input using the stability theory of Lyapunov function cam be applied. Therefore, the controlled system have the robustness against disturbances and can be stabilized because of reinforced adaptivity. This proposed fuzzy controller is implemented on a 80586 micro-computer which have of fuzzy inference routine part, manipulating part of scale factors and DT-2801 data aquisition board.

• 한국측량학회지
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• 제36권2호
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• pp.75-84
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• 2018

본 연구의 목적은 MEMS 기반의 INS를 적용한 저가형 MMS를 개발하고, 개발된 MMS를 이용하여 x, y의 평면 거리오차가 0.546m인 정확도를 확보하여 도로시설물의 판독에 활용하고자 함에 있다. MMS 기술은 해외 유수의 측량장비제작 업체를 중심으로 지리정보 구축을 위한 새로운 측량기술로 활발하게 사용되고 있지만 국내에서는 아직 관련 연구가 초기단계에 있다. 또한, MMS 장비개발은 몇몇 연구원 및 업체에서 시도를 하였으나 안정화가 이루어지지 않은 시작품 단계에 불과하다. 이러한 MMS 기술은 빠른 시간 내에 지형 지물 데이터를 취득할 수 있어 정밀지도 제작과 도로시설물 데이터 취득에 활용되고 있다. 따라서 본 연구에서는 MMS 제작에 사용하는 각종 센서(LiDAR, CCD camera, GPS/INS, DMI 등)를 동기화하여 MEMS 기반의 INS를 탑재한 저가형 MMS를 개발하고자 한다.

• 한국화재소방학회논문지
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• 제29권6호
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• pp.98-108
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• 2015

자연 재해 또는 대형 인적 재난 현장과 같은 특수재난현장의 지휘본부에서는 소방관의 안전과 효과적인 지휘 통제를 위한 통합 지휘시스템은 매우 중요하다. 통합지휘시스템은 특수재난현장의 온도, 습도, 이산화탄소 등의 환경 정보와 현장 상황을 파악할 수 있는 영상 정보 및 소방관의 맥박, 공기통 잔량 등의 개인 신체 정보를 필요로 한다. 수집된 정보들은 Analog to Digital Converter (ADC) 칩을 거쳐 디지털 신호로 변경되고 Micro Controller Unit (MCU)가 직렬 통신 방식인 Serial Peripheral Interface (SPI) 통신 방식으로 이용하여 송신 보드로 디지털 신호를 전송한다. 송신 보드에 저장된 디지털 신호는 Radio Frequence (RF) 송신기를 이용하여 통합지휘시스템으로 전송된다. 자이로센서 및 관성센서를 이용하여 건물 내부에 있는 진압대원의 위치를 확인한다. 수집된 정보는 소방관의 안전과 효과적인 지휘를 할 수있는 통합 지휘 시스템을 위한 각종 정보로 활용된다. 본 연구는 무선 전송 기술, 실내 측위기술 및 통합지휘시스템에 전송 된 정보를 이용한 의사결정 지원 통합지휘시스템 대하여 이론적 및 실험적으로 연구한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1508-1511
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• 1996

In the fields of the optics, precise machine, semiconducting processing, the micro-positioning actuators are required for the control of position in submicron range. In this study, dielectric properties of 0.5PNN-(0.5-x)PZN-xPZT system ceramics with different PZT mole ratio were investigated. As the amount of PZT incerases, curie temperature was increased. The maximum of dielectric and piezoelectric constant was shown at 0.3 mole ratio of PZT amount. As a results, we have found that the structrue of ceramics with PZT 0.3 mole was morphotropic phase boundary.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.52-60
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• 2005

Ultra-precision positioning systems basically require high natural frequency and sufficient workspace. To cope with this requirement, flexure hinge mechanisms have been developed. However, previous designs are difficult to satisfy the functional requirements of the system due to difficulty in modeling and optimization process applying fur the independent axiomatic design. Therefore, this paper suggests a new design and design procedure based on semi-coupled, axiomatic design. A spatial 3-DOF parallel type micro mechanism is chosen aa an exemplary device. Based on preliminary kinematic analysis and dynamic modeling of the system, an optimum design is conducted. To check the effectiveness of the optimal parameters obtained by theoretical approach, simulation has been performed by FEM.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.87-94
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• 2013

UKF (Unscented Kalman Filter) has been used in the nonlinear systems without initial accurate state estimates instead of EKF (Extended Kalman Filter) of the last decade because the UKF has robustness to the large initial estimation error. In the multirate integrated system such as INS (Inertial Navigation System)/GPS (Global Positioning System) integrated navigation system, however, it is difficult to implement the UKF based navigation algorithm in the mid-grade micro-processor due to the large computational burden. To overcome this problem, this paper proposes a MUKF (Modified UKF) that has a reduced computation burden using the basic idea that the change of the provability distribution for the state variables between measurement updates is small in the multi-rate INS/GPS integrated navigation filter. The performance of the proposed MUKF is verified by numerical simulations.

• 항공우주시스템공학회지
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• 제12권6호
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• pp.9-16
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• 2018

본 논문에서는 반작용휠 미소진동시험 결과 및 유한요소모델 기반 광기계해석 통합모델을 이용해 영상품질저하 예측을 실시하고 해석결과를 바탕으로 기준 회전수에서 영상품질관점에서 최적의 반작용휠 배치조합을 찾는 것을 목적으로 한다. 위성은 적절한 기동성능을 위하여 여러 개의 반작용휠을 장착하는데 반작용휠에서 발생하는 미소진동은 위성영상품질 열화에 원인이 된다. 같은 반작용휠이라도 제조과정상 발생하는 제품의 진동특성차이가 있으며 이를 반영한 반작용휠의 배치설계는 최종 위성영상 성능품질 열화를 최소화시킬 수 있다. 이를 위해 본 연구에서는 모든 반작용휠의 배치상태를 선정하고 이에 따른 영상품질 열화해석을 실시하여 최소의 열화가 일어나는 반작용휠 배치조합을 찾아내었다.

• 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.