• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.503-504
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• 2008

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1753-1754
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• 2006

이 논문에서는 밀폐된 공간 내에서 발생하는 소음을 줄이기 위해 일종의 능동 소음 제어 방법을 발표한다. 제안된 제어방법은 WPFB(Wavelet Packet Filter Bank)를 이용하여 기존의 FXLMS(Filtered-X Least Mean Square) 알고리즘의 단점인, 소음 제어시스템 내에서의 소음전달의 지연으로 인한 불안정성과, 소음의 급작스런 변화에 대한 응답능력부족을 해소하는 방법이다. 이 시스템의 주요 특성은 소음제어 시스템의 이차경로에 WPFB이 삽입되어 FXLMS 알고리즘에 비해 빠른 연산이 수행된다는 것이다. 다른 말로 하면, WPFB는 병렬연산을 수행한다. 그러면, 적응 알고리즘 내에 있는 필터의 웨이트들이 더 빨리 갱신될 것이다. 또한 WPFB는 뛰어난 분해능을 가지고 있어서 아주 미세한 소음까지도 처리해 낼 수가 있다. 이 제어기법의 효율성은 simulation을 통해 증명될 것이다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.260-265
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• 2014

Recently, many active noise control (ANC) systems, which employ the adaptive filter controlling method, have been reported for eliminating unwanted noise. ANC systems based on the filtered-X least mean square (FXLMS) algorithm have a problem with compensating the acoustic feedback of secondary route. It is difficult to apply the real time, because transfer function of secondary route must be measured by off-line method to solve this problem. In this paper, we propose the ANC system that applies a correlation LMS(CLMS) algorithm for improving a problem of transfer function measurement. The proposed algorithm is based on input of road noise. The proposed ANC systems have an advantage of real-time process without degradation of performance, although there are many calculation compared with FXLMS algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.897-905
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• 2006

This study considers an experimental design of disturbance compensation control to improve stabilization performance of main battle tanks. An adaptive non-parametric design technique based on the Filtered-x Least Mean Square(FXLMS) algorithm is applied in the consideration of model uncertainties. The optimal compensator is designed by two-step design procedures: determination of frequency response function of the disturbance compensator which can cancel the disturbance of series of single harmonics by using the FXLMS algorithm and determination of the compensator polynomial which can fit the frequency response function obtained in the first step optimally by using a curve fitting technique. The disturbance compensator is applied to a simple experimental gun-torsion bar-motor system which simulates gun driving servo-system. Along with experimental results, the feasibility of the proposed technique is illustrated. Experimental results demonstrate that the proposed control reduces the standard deviation of stabilization error to 47.6% that by feedback control alone. The directional properties of the FXLMS Algorithm such as the direction of convergence and its convergence speed are also verified experimentally.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.27-31
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• 2012

In this paper, we constructed an array of speaker system with directivity by using FXLMS(Filtered-X LMS) algorithm and confirmed its directivity. The front $0^{\circ}$ characteristics of the controlled speaker was suppressed by interfering it with the control signal produced with filter coefficients optimized with respect to the $180^{\circ}$ characteristics of the rear speakers. The directivity of the array of rear speakers was measured and the damping effect of the signal from the front speaker array was confirmed. The frequency characteristics and directivity was investigated by using the adaptive filter coefficients on damping, the damping on the control point was verified in all the frequency range. In 100Hz, 200Hz, 1000Hz regime, the damping effect was observed in the range of front $60^{\circ}{\sim}100^{\circ}$.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.83-91
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• 2004

This paper illustrates the feasibility and the effectiveness of the disturbance feedforward compensation control proposed in the previous paper. The compensator is designed experimentally by means of the Multiple Filtered-x Least Mean Square algorithm. A 2-DOF active magnetic bearing system subject to base motion is built and the compensation control is applied. The experimental results demonstrate that the compensation control reduces the air-gap responses within 10$%$ of those by the feedback control alone without increasing the control inputs.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.74-82
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• 2004

In this paper, a disturbance feedforward compensator design technique is proposed for an active magnetic bearing system subject to base motion for attenuating disturbance responses. In the consideration of the requirements on the model accuracy in the model based compensator designs, an experimental feedforward compensator design based on adaptive estimation by means of the Multiple Filtered-x least mean square(MFXLMS) algorithm is proposed. The performance and the effectiveness of the proposed technique will be presented in the succeeding paper in which the proposed technique is applied to a 2-DOF active magnetic bearing system subject to base motion.

• Proceedings of the KIEE Conference
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• 2008.04b
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• pp.207-210
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• 2008

변압기에서 발생하는 소음은 근무자의 작업환경을 열악케 하는 직접적인 요인이 될 뿐만 아니라 정신적인 스트레스를 받게 되어 작업능률 저하 및 변전소 인접 주민들의 일상생활 환경을 저해하는 요인이 되고 있다. 본 연구에서는 이러한 문제점을 개선하기 위하여 FXAMS 알고리즘을 적용한 변압기의 능동소음제어에 대한 연구를 수행하였으며, 다중음 다채널 제어가 가능한 시스템을 개발하여 현장에 적용한 결과, 120Hz에서는 9.06[dB]의 능동소음감쇄가 이루어졌으며, 전체적으로 4.55[dB]의 감쇄효과가 얻을 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.447-450
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• 2003

This paper concerns on application of active magnetic bearing(AMB) system to levitate the elevation axis of an electro-optical sight mounted on moving vehicles. In such a system. it is desirable to retain the elevation axis within the predetermined air-gap while the vehicle is moving. A disturbance compensation control is proposed to reduce the base motion response. In the consideration of the uncertainty of the system model, a filtered-x least-mean-square(FXLMS) algorithm is used to estimate adaptively the frequency response function of the feedforward control which cancels disturbance responses. The frequency response function is fitted to an optimal feedforward control. Experimental results demonstrate that the proposed control reduces the air-gap deviation to 27.7% that by feedback control alone.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.379-380
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• 2007

본 연구에서는 대용량변압기의 주 소음원인 120[Hz]와 240{Hz] 및 360[Hz] 주파수에 대한 다중음을 다채널(4채널)의 FXLMS 알고리즘을 적용한 변압기 소음 감쇠시스템을 구축하고 현장실험을 통해 소음이 저감되는 것을 확인하였다.