• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.204-209
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• 2004

Recently, the various performances of vehicle are rapidly improved. Therefore tire noise is recognized as important noise source because vehicle noise is considerably reduced. This study is performed for the control of the cavity resonance noise that is structure-borne noise, due to fluid(air)-structure interaction. For this investigation, FRF analysis has been carried out using FEM and we found an important factor affecting cavity resonance. The effect of this factor is confirmed by objective noise test. We confirmed that the result of FRF analysis and objective noise test is that the structure control of tire sidewall can reduce cavity resonance noise due to fluid-structure interaction

• 대한기계학회논문집
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• 제15권1호
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• pp.90-97
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• 1991

본 연구에서는 하이브리드 스텝핑 모터의 공진 배제를 위한 폐회로제어시스템 을 개발하였고 펄스 발생, 위치 및 속도변화, 가감속제어, 정여괴전방향결정, 카운트 및 스텝핑 모터의 온/오프기능 등을 하드웨어 대신 마이크로컴퓨터를 이용한 소프트웨 어로 대치하였으며, 구동회로의 복잡함을 피하기 위해 스텝핑 모터의 전용제어기인 PMM8713IC를 사용하였고 궤환정보는 샤프트 엔코더를 사용하였다.그리고 리드 스크 루우를 사용한 1축 테이블을 제작하여 개회로제어시와 폐회로제어시의 동특성 및 공진 현상을 검토하였다.

• 전기학회논문지
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• 제62권10호
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• pp.1487-1493
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• 2013

A new simple control method for active power filter, which can realize the complete compensation of harmonics is proposed. In the proposed scheme, a model-based digital current control strategy is presented. The proposed control system is designed and implemented in a form referred to as internal model control structure. This method provides a convenient way for parameterizing the controller in term of the nominal system model, including time-delays. As a result, the resulting controller parameters are directly set based on the power circuit parameters, which make tuning of the controllers straightforward task. In the proposed control algorithm, overshoots and oscillations due to the computation time delay is prevented by explicit incorporating of the delay in the controller transfer function. In addition, a new compensating current reference generator employing resonance model implemented by a DSP(Digital Signal Processor) is introduced. Resonance model has an infinite gain at resonant frequency, and it exhibits a band-pass filter. Consequently, the difference between the instantaneous load current and the output of this model is the current reference signal for the harmonic compensation.

• 조명전기설비학회논문지
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• 제17권4호
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• pp.36-44
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• 2003

전동기와 부하가 강성이 작은 축으로 연결되는 산업용 전동기 구동시스템에 있어서 전동기의 관성과 부하의 관성에 의해 축에 비틀림 진동이 발생한다. 이러한 문제를 해결하기 위하여 기존에 2자유도 H$_{\infty}$제어기가 제안되었다. 그러나 이 제어기는 구현하는데 어려움이 있다. 본 논문에서는 부분적인 상태궤환과 공진비제어를 이용한 2관성계의 H$_{\infty}$제어가 제안되었다. 제안된 제어기는 간단하면서도 외란 및 진동억제 성능을 만족한다.어기는 간단하면서도 외란 및 진동억제 성능을 만족한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.512-517
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• 1994

The control system of a precise positioning mechanism with resonance and Coulomb friction has been designed using H$_{\infty}$ control theory, and the control performance has been verified by computer simulation and experimental analysis. The DGKF type H$_{\infty}$ control theory with scalar weighting factors was utilized for designing the control system. The followings have been confirmed from the present study: (1) The system with H$_{\infty}$ control presents better convergence and stability than the system with conventional control (PI-notch filter control). (2) The H$_{\infty}$ control system have good robustness properties for a wide range of operating conditions in the presence of external disturbances such as Coulomb friction and changing mechanical resonant frequency.ncy.

• 전기학회논문지
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• 제66권4호
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• pp.643-650
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• 2017

This pap4er analyzes resonance characteristics of a slave motor that is not controlled by load and parameter differences between Dual motors during parallel operation in middle-low speed. Dual SPMSMs(Surface mounted Permanent Magnet Synchronous Motor) connected in parallel to a single inverter controlled by the master and slave control in this paper. Based on the stability analysis of the SPMSM for a variation of torque angle, the 6th nonlinear state equation of the torque angle variation in the SIMM(Single Inverter Multi Motor) structure is derived according to a mathematical model for the dual motors. In general, an analysis of the 6th order nonlinear state equation is complex. Therefore, a resonance frequency generated from the slave motor is found from the characteristic equation of the 2nd order system obtained by linearization and model reduction near steady state operation point. Through simulations and experiments, it is confirmed that the stability analysis of the SPMSMs and state equation models are useful for the variation of the torque angle analyzed in this paper.

• 대한전자공학회논문지TC
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• 제47권11호
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• pp.77-83
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• 2010

본 논문은 2.4 GHz 와 5 GHz 대역에서 802.11n 규격에 사용가능한 이중 공진 PIFA(Planar Inverted F-Antenna)를 제안하였다. 이중 공진을 위해 2.4 GHz 대역에서는 패치, 5 GHz 대역에서는 U-형 슬랏을 이용하여 PIFA를 설계하였다. 단락판과 급전핀의 위치, 단락판의 폭, U-형 슬랏의 두께, U-형 슬랏의 위치를 변경시키며 HFSS(High Frequency Structure Simulation)를 이용하여 안테나의 특성변화를 조사하였다. 실제 시제품을 제작하여 측정한 값과 시뮬레이션 값을 비교 분석한 결과, U-형 슬랏의 위치가 급전핀과 멀어질수록, 그 두께가 얇을수록 안테나의 특성이 좋아지는 것을 알 수 있었다.

• 한국소음진동공학회논문집
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• 제20권12호
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• pp.1128-1138
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• 2010

정밀 방진에서 전형적인 문제로 고하중으로 인한 저주파 공진 특성이 있다. 전자기 에어 스프징은 진동 제어 장치이자 능동형 방진 장치이다. 이 연구에서 전자기 에어 스프링은 반도체 생산을 위한 저주파 공진을 제거하는 것을 목적으로 한다. 능동형 방진 장치로 기계 및 전가 부분은 2.5톤의 하 중에 작동되도록 설계하였다. 전자기 스프링은 탄성 공압 챔버 내에 공기압을 이용하여 띄우고, 전자기 된 시스템에 의하면 공진 주파수 영역에서 제어 시간 및 최고 피크가 상당히 줄어들었고, 그 결과 피동형 시스템 상의 고유 진동에 의해 발생되는 공진을 피할 수 있음을 보였다.

• 대한치과보철학회지
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• 제45권3호
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• pp.339-344
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• 2007

Statement of problem. Various anodic oxidation techniques can be applied to dental implant surfaces. But the condition for optimal anodized surfaces has not been described yet. Purpose. The purpose of this investigation was to compare an implant that was oxidized by another method with $TiUnite^{TM}$ through resonance frequency analysis and histomorphometry. Material and methods. Turned (control), $TiUnite^{TM}$ and another oxidized fixtures, which used $Ca^{2+}$ solution for anodic oxidation, were placed in the tibiae of 5 New Zealand White rabbits. The bone responses were evaluated and compared by consecutive resonance frequency analysis once a week for 6 weeks and histomorphometry after a healing period of 6 weeks. Results. At the first week, both oxidized implants showed significantly higher implant stability quotient (ISQ) values than the control. No significant differences in resonance frequency analysis were found between the two oxidized groups for 6 weeks. The means and standard deviations of bone-to-implant contact (BIC) ratios were $71.0{\pm}4.2$ for $TiUnite^{TM}$, $67.5{\pm}10.3$ for the $Ca^{2+}$-based oxidation fixture, $22.8{\pm}6.5$ for the control. Both oxidized implants were significantly superior in osseointegration to the turned one. There was, however, no statistically significant difference between the two oxidized implants. Conclusion. $TiUnite^{TM}$ and the $Ca^{2+}$-based oxidation fixture showed superior early bone response than the control with respect to resonance frequency analysis and histomorphometry. No significant differences between the oxidized groups, however, were found in this investigation using the rabbit tibia model.

• Journal of Power Electronics
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• 제15권5호
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• pp.1409-1420
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• 2015

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.