• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.507-515
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• 2015

This study was conducted to develop and verify a torque application device for use in a mechanical power-circulation test rig for 5.5 MW wind turbine gearboxes. The design and analysis of the torque application device was conducted. In addition, the torsional stiffness of the test rig was calculated using the rotational angle measurements for each of the components. The calculated stiffness of the test rig was $231.13kN{\cdot}m/rad$ for a clockwise torque application. The rated torque can be applied when the stiffness of the gearbox is greater than $1,064,400kN{\cdot}m/rad$ for a clockwise torque application. Because of the limited rotational angle of the test rig, the potential application of the rated torque is determined according to the torsional stiffness of the test gearbox.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1853-1855
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• 2005

본 논문에서는 카메라폰용 광학줌(Optical zooming)과 자동초점조절장치(Auto Focusing, AF)에 쓰일 초음파모터를 제작하였다. 초음파모터의 제작 및 시뮬레이션은 유한요소해석 프로그램인 ATILA 5.2.1(Magsoft)를 사용하여 디자인설계에 따른 구동특성을 고찰하였고 세자된 초음파모터는 한쪽 면이 없는 사자형의 탄성체를 제작하였으며 탄성체의 양쪽 다리에 각각 압전체를 부착하였다. 또한 압전세라믹의 조성은 $0.9Pb(Zr_{0.51}Ti_{0.49})O_3$-$0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$의 조성으로 설계하였고 시편의 제조는 7-layer로 적층하였다. 제작된 압전세라믹의 치수는 $6*2*0.35mm^3$ (길이*폭*두께)로 제작하였다. 또한 탄성체의 외형치수는 $10*10*2mm^3$ 제작하였으며 두께를 각각 0.3[mm], 0.5[mm], 0.8[mm]으로 변화시키며 제작하였다. 두께가 0.8[mm]인 경우 공진주파수 60.5[kHz]를 나타내었으며 초음파모터의 압전세라믹에 인가전압이 증가함에 따라 회전속도와 모터에 흐르는 전류는 증가하였다. 인가전압이 40[Vpp], 공진주파수는 60.5[kHz]일때 무게추를 달고 그때의 토크 및 효율을 측정하였다. 회전 속도는 토크가 증가함에 따라 거의 선형적으로 감소하였으며 효율은 토크에 따라 증가하다가 토크가 약 20(mNmm)일 때 약 28[%]로 최대치를 나타내었다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2033-2035
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• 2001

본 연구는 기존의 자전거에 전기 구동장치를 장착시켜서 자전거의 페달링에 의하여 검출된 답력을 이용한 보조 동력 구동장치에 대한 개발이다. 답력의 검출은 불시의치차를 이용한 동력 전달장치를 이용하였다. 이 장치의 입력기어에서 출력기어로 동력을 전달하는 아이들 피니언 기어와 결합된 캐리어를 동력 전달시 발생하는 반력에 의한 각도를 이용하여 토크량을 측정하였다. 동력전달을 할 경우 발생하는 반력에 의한 회전각을 자기센서를 이용하여 답력을 측정하였다. 이 답력을 구동회로에 인가하여 보조동력을 자전거에 인가함에 따라 주행을 쾌적하게 하도록 개발하였으며 실험을 통하여 실용성을 고찰하였다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.98-100
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• 2006

본 논문은 매입자석형 동기전동기 (Interior Permanent Magnet Motor, 이하 IPM)의 Sensorless 제어에 관한 것이다. IPM에서 벡터제어를 수행하기 위해서는 계자분 전류와 토크분 전류로 나누어서 제어를 해줘야 한다. 이때, 토크는 영구자석과 직교하는 방향으로 토크분 전류를 인가해줘야 하기 때문에, 영구자속에 의해 발생하는 자속의 정확한 위치를 알아야 하고, 그로 인하여 엔코더 등의 자극위치센서를 사용해야 한다. 따라서, IPM은 일반적으로 Sensored제어를 하게 된다. 그러나, 고가의 장치인 엔코더 등의 자극위치센서를 사용하지 않고 적절한 제어를 수행해주기 위하여 여러 sensorless 기법들이 개발되어 발전되었다. 본 논문에서는 자속추정기를 이용하여 자속을 추정하고, 이를 이용하여 모터의 회전속도 및 회전각을 추정함으로써 Sensorless제어가 가능하였다. 본 제어 알고리즘은 자사 벡터제어 인버터인 iV5를 통해 실험하여 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2618-2624
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• 2009

Harmonics (or distortion in wave form) has always existed in electrical power systems. It is harmless as long as its level is not substantial. However, with the recent rapid advancement of power electronics technology, so-called nonlinear loads, such as variable frequency drives for motor power/speed control, are increasingly finding their way to shipboard or offshore applications. In this paper a new approach to direct torque control (DTC) of induction motor drive is presented. In comparison with the conventional DTC methods the inverter switching frequency is constant and is dramatically increased, requiring neither any increase of the sampling frequency, nor any high frequency dither signal. The well-developed space vector modulation technique is applied to inverter control in the proposed DTC-based induction motor drive system, thereby dramatically reducing the current harmonics. As compared to the existing DTC approach with constant inverter switching frequency, the presented new approach does not invoke any concept of deadbeat control, thereby dramatically reducing the computations.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.507-509
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• 2023

본 논문에서는 DSP (Digital Signal Processing)를 이용한 차량용 레이다 수평안정화장치 구동 전략을 제안한다. 지대공 유도 미사일용 차량용 레이다는 전방향으로 일정 속도로 회전하며 감시정찰 임무를 수행한다. 수평안정화장치는 4세트의 수평구동모듈을 이용하여 차량 플랫폼의 수평을 유지하여 레이다의 안정적인 회전을 가능하게 한다. 이를 실시간으로 구현하기 위해 임베디드시스템인 DSP를 적용하여 경사도를 측정하고, 구동모듈에 구동 명령을 인가하여 수평을 유지한다. 수평구동모터는 감속기를 통하여 모터 토크를 증가시켜 수평 안정 동작을 수행한다. 본 논문에서는 수평구동모듈 1세트를 모델링하여 수평안정화장치를 축소 구현한다. 제안하는 구동 전략의 유효성은 시뮬레이션으로 입증한다.

• Science of Emotion and Sensibility
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• v.7 no.4
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• pp.19-24
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque. Therefore, the estimation of damping property from the isokinetic movement is difficult.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.437-442
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• 2014

The equipment or with a constant torque and a variable stress due to axial vibration such as the turbine-generator system in nuclear power plant show the fatigue fracture behavior. Thus this study whoul aim to measure the torsional stress and analyze the fatigue fracture behavior. To achieve this, we manufactured the equipment similar with turbine-generator system and applied various torsional vibration stress due to external load. In particular, the evaluation was conducted with the existing evaluation methods of the fatigue behavior of known stress-life, strain-life, crack growth assessment methods. With increasing the external load and independent methods tends to decrease the fatigue life was confirmed up to 10 times in 5 kV external load compared to without external load.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.139-141
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• 2017

By modulating the flow rate of $N_2O$ into a HR motor assembly, a control valve of a hybrid rocket engine plays a role to increase or decrease the thrust. In this study, the control valve has been designed to meet the requirements which are response speed(${\leq}$ about 1 second) and torque(${\geq}$ about $36N{\cdot}m$). Then, when analog signal 0~10V is applied, the situation where the valve is opened and closed has to be realized. To do this, the data values have to be entered into the actuator. Finally, the performance evaluation of the control valve has been performed to validate this product.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.170-177
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• 2020

This study examined the clamping force control method and the braking performance test results of an electromechanical brake (EMB) using braking test equipment. Most of the studies related to EMBs have been carried out in the automotive field, dealing mainly with the static test results for various control methods. On the other hand, this study performed a dynamic performance evaluation. The three-phase interior permanent magnet synchronous motor (IPMSM) was applied to drive the actuator of the EMB, and the analysis was verified by JMAG(Ver. 18.0), which is finite element method (FEM) software. The current control, speed control, and position control were used for clamping force control of the EMB, and the maximum torque per ampere (MTPA) control was applied to the current controller for efficient control. The EMB's emergency braking deceleration performance was tested in the same way as conventional pneumatic brake systems when the wheel of a train rotates at 110 km/h, 230 km/h, and 300 km/h. The emergency braking time, with the wheel stopped completely at the maximum rotational speed, was approximately 73 seconds. The similarity of the braking time and deceleration pattern was verified through a comparison with the performance test results of the pneumatic brake system applied to the next generation high-speed railway vehicle (HEMU-430X).