• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.410-410
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• 2000

Impedance control is recognised as one of the most proper control scheme to carry out the assembly tasks, since it can control the dynamic relationship between the manipulator and environment directly. However, it is well known that the contact force cannot be controlled directly using the impedance control. Also impedance parameters should be properly defined depending on the task to be performed. We propose a new position based impedance control, which has self-adjusted impedance parameters and can control the contact force explicitly, Impedance parameters, as time-varying parameters, are adjusted automatically based on the measured contact force and the position error during the task. A proposed algorithm was implemented on the peg-in-hole task with the industrial manipulator. We shows the effectiveness of proposed control method experimentally.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.110-115
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• 2021

A multi-band, compact, and complex vehicle roof antenna has become important in terms of car exterior design and multi-functions which include Radio, DAB/DMB, SXM, GNSS, Telematics, and V2X. In this paper, we propose a compact multi-band V2X pole-type roof antenna. Using impedance change characteristic, a single pole antenna which has multiband such as radio, DAB/DMB, telematics, and V2X band is proposed. With two patch antennas for GNSS and SXM, the dimension of a multiband roof antenna is 131x63x37mm only.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.2
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• pp.103-109
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• 2008

This paper presents a new method for designing a ballast that can provide dimming control of an electrodeless fluorescent lamp. Frequency control of lamp power is inappropriate because the lamp coefficients such as equivalent impedance, coupling coefficient of the transformer, and plasma resistance are a function of lamp power. In this paper, the dimming is achieved by controlling the DC_Link voltage in relation to the lamp power. The DC_Link voltage is controlled by a buck converter. Simulation and experimental results of the proposed design method are presented in order to validate the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1513-1519
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• 2000

This paper proposes a hybrid control method of using impedance control and the computed-torque control for biped robot locomotion. Computed torque control is used for supporting (constrained) leg. For the free leg, the impedance control is used, where different values of impedance parameters are used depending on the gait phase of the biped robot. To reduce the magnitude of an impact and guarantee a stable footing when a foot contacts with the ground, this paper proposes to increase the damping of the leg drastically and to modify the reference trajectory of the leg. Computer simulations with a 3 -dof environment model for which a combination of a nonlinear and a linear compliant models is used, show that the proposed controller is superior to the computed-torque controllers in reducing impacts and stabilizing the footing.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.7-14
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• 2008

In this paper, we propose VATL(Voltage-controlled Artificial Transmission Line) employing periodically loaded diodes for application to on-chip matching components on MMIC. Compared with conventional microstrip line, the VATL showed a much shorter wave length due to periodic capacitance of diodes, and the characteristic impedance of the VATL was easily controlled bγ changing supplied voltage. Concretely, the characteristic impedance of the VATL was changed from $80{\sim}20{\Omega}$ in a range of $0{\sim}1.05V$ and the VATL showed a wavelength of 1.5mm at 20GHz, while conventional microstrip line showed a wavelength of 5.3mm at the same frequency. Using the VATL, a ${\lambda}/4$ impedance transformer was fabricated on GaAs MMIC for application to on-chip matching components on MMIC. Using the ${\lambda}/4$ impedance transformer made it possible to perform impedance matching between RF components with various characteristic impedance of $30{\sim}100{\Omega}$ by adjusting applied Voltage.

• Journal of IKEEE
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• v.23 no.4
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• pp.1473-1476
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• 2019

Accurate material information is very important in PCB (Printed Circuit Board) design. In an integrated mast of a battleship, heat reduction is essential for stealth functionality. So heat dissipation from internal control equipments should be reduced as much as possible. Control equipments mostly consist of PCBs, but it often suffers from impedance mismatching due to imprecise Dk (Dielectric Constant), which significantly increases heat dissipation. In this paper, measurement methods of Dk is investigated. Also, effects on impedance mismatch by Dk variation with operating frequency is investigated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1047-1053
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• 2011

In this paper, we proposed an HF-band wireless power transfer system with adaptive frequency control circuit for efficiency enhancement in a short range. In general, a wireless power transfer system shows an impedance mismatching due to a reflected impedance, because a coupling coefficient is varied with respect to separation distance between two resonating loop antennas. The proposed method can compensate this impedance mismatching by varying input frequency of a voltage-controlled oscillator adaptively with respect to separation distance. Therefore, transmission efficiency is enhanced in a short distance, where large impedance mismatch occurs. The adaptive frequency circuit consists of a directional coupler, a detector, and a loop filter. In order to demonstrate the performance of the proposed system, a wireless power transfer system with adaptive frequency control circuits is designed and implemented, which has a pair of loop antennas with a dimension of 30${\times}$30 $cm^2$. From measured results, the proposed system shows enhanced efficiency performance than the case without adaptive frequency control.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.229-230
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• 2016

기존 자가발전 운동기구용 컨버터의 경우, 운동레벨을 조절하기 위한 입력임피던스 조절기능이 없거나, 조절기능을 추가하는 경우 복잡한 topology를 동반되는 경우가 일반적이다. 또한 복잡한 회로를 추가하게 되면 회로의 전체적인 부피가 증가하고, 원가가 상승할 뿐만 아니라, 회로의 신뢰성도 현저하게 저하시키는 등 회로 상용화를 어렵게 만든다. 본 논문에서는 입력 전압 및 전류 제어 방식을 이용하지 않고, 컨버터 구조 자체로 입력 임피던스를 제어하는 방식을 제안한다. 제안 방식은 입력전압, 입력전류 두 가지의 제어를 실행하지 않음으로써 복잡한 피드백 제어 단의 삭제가 가능하며, 이를 통해 회로의 높은 신뢰성 및 부피, 원가 감소 효과를 얻을 수 있다. 본 논문에서는 Flyback 컨버터를 이용하여, 이론적 특성 분석과 200W급 시작품을 통한 실험적 분석을 통해 그 타당성을 검증한다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.109-110
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• 2011

본 논문은 배터리 에너지 저장 시스템(Battery Energy Storage System, BESS)에 사용된 대용량 리튬이온 배터리의 등가 모델링을 제안하였다. 리튬 배터리의 전기화학적 특성을 고려한 임피던스 등가모델을 선정한 후 등가모델의 파라미터를 추출하였으며, 추출된 파라미터와 SOC(State-of Charge)와의 관계를 살펴보았다. 본 연구를 통하여 얻어진 파라미터를 이용하면 BESS 제어시 배터리 특성을 파악할 수 있으므로, 배터리의 최적제어 및 시스템의 신뢰성을 높일 수 있을 것으로 기대된다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.181-182
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• 2012

마이크로그리드 계통 연계 운전시 분산 발전은 main grid와 함께 연계되어 부하의 수요를 담당한다. 하지만 계통사고나 의도적인 제어 전략으로 인해 분산 발전은 계통과 분리되어 단독으로 부하의 수요를 담당하게 된다. 이때 분산발전을 기반으로 한 인버터는 계통 연계 운전 시 하나의 전류원으로서의 역할을 하다가 시스템이 단독 운전 모드로 전환시 전압원으로 가정되게 된다. 이러한 특성으로 인해 단독운전 모드시의 인버터 병렬 운전은 시스템 파라미터와 라인 임피던스에 매우 민감해진다. 따라서 본 논문에서는 단독운전 모드시 불평형 저전압 마이크로그리드에서 대두되는 문제들에 대해 분석하고 가상 인덕터와 기준 전압 조정을 활용한 개선된 드룹 방식의 적용을 통해 이를 해결하고자 하였다. 제안된 이론은 PSIM 시뮬레이션을 통해 검증되었다.