• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.537-537
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• 2010

이 논문에서는 음향 임피던스를 제어하는 능동형 소음 제어 방법을 연구하였다. 관의 끝단에 스피커를 이용하여 음향 임피던스를 제어하게 된다. 음향 임피던스 제어는 음향의 반사를 최소화 하는 제어 방법을 이용하는 것으로, 닫힌 관의 끝단에 음파의 흡수와 반사를 제어한다. 나아가 음향 임피던스 제어 방법은 관의 중앙에 설치되어 적용된다. 이 경우에는 음향의 반사, 흡수 및 전달이 측정되고, 최소화하기 위한 임피던스가 계산된다. 이를 위해 가진기, 마이크로폰, 진동측정용 레이저 바이브로미터, 그리고 능동 소음 제어 하드웨어로 구성된 시스템을 구축하고 검증하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.49-56
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• 2022

In this study, numerical simulations for reducing noise between floors in an apartment building was carried out using Active Noise Control (ANC) technology. In order to examine the feasibility of using ANC to reduce noise between floors, accelerometers and microphones for noise collection were installed in the inter-floor noise test facility to measure noise and vibration caused by the impact ball drop test. By using the measured data, Filtered-x Least Mean Square (Fx-LMS) algorithm-based ANC simulations were carried out. In the simulations, after deriving optimal simulation conditions including the adaptive control convergence coefficient, the noise reduction effect was analyzed through numerical simulations using the number of installed accelerometers and speakers as variables. Finally, it was confirmed that the noise between floors could be reduced using ANC technology under limited conditions.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.153-163
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• 1999

본 연구에서는 격자패널을 통한 소음전달을 감소시키기 위하여 외부 구조적 가진으로부터 유발된 경량 패널의 진동을 능동 제어하는 기법을 기술한다. 최적 되먹임제어기와 적응 앞먹임제어기가 결합된 혼합형 제어기가 진동제어기로 사용된다. 되먹임제어기는 주파수 영역의 모델규명법에 의해 추출된 다중 입/출력 패널진동계 모델에 대하여 LQG 최적기법을 이용하여 감쇠능을 향상시키도록 설계된다. 앞먹임제어기는 되먹임 궤환의 결합효과를 자동적으로 보정할 수 있는 제안된 학습법칙에 기초하여 패널의 잔류진동이 최소가 되도록 적응된다. 45.7${\times}$45.7${\times}$2.54 ${cm^3}$ 벌집형상의 고강도 패널, 4개의 관성형 구동기 및 이산신호처리장치에 의해 구현된 패널 진동계에 대한 능동제어 실험을 수행해 본 결과 600Hz 주파수대역에 대한 12dB 진동저감이 이루어 질 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.41-46
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• 2005

Acoustic problems in the environment have gained attention due to the noise and vibration contact often in industry as well as life on modem society. Noise is one of safety element in industry, this proves damaging to humans from both a physical and a psychological aspect and so drop working efficiency. Various noises are happened from machines of manufacturing process in PCB industry. This paper present a new approach for subband feedback Active Noise Control (ANC) using Mel scale for headset system in PCB industry. The proposed Mel scale subband algorithm had a performance advantage over the subband algorithm in the noise attenuation and convergence time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1573-1581
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• 1996

This paper present as experimental demonstratio of DSP and a sensory actuator that is used to actively control sound transmission/radiation through a vibrating plate. A plane acoustic wave incident on a clamped, thin circular plate was used as a noise source, and a sensory actuator bounded to the plate was used to control and sense vibration of the plate. The sound transmission reduction problem was tranformed as a structural vibration control problem that actively control the structural vibration modes coupled to acoustic modes. The results show that the first structural vibration mode is controlled with a reduction of 78 percent in the displacement and velocity of the plate. This corresponds to a 13dB reduction in the acoustic response. These experimental results indicate that a sensory actuator bounded to the plate can be employed to attenuate the sound transmitted to radiated from the plate.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.991-995
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• 2002

The engine booming noise heard inside a vehicle's cabin is due to the engine vibration that's transferred to the chassis in the form of structural vibration and it often causes discomfort to the passenger. In an effort to seek out the possible relation between the engine booming noise and the engine vibration of a vehicle, a position on the engine mount was selected and the vibration transmission through the position was attenuated to observe the corresponding change in the noise level inside the cabin. A system consisting of an actuator and a hybrid controller that has both the feed-forward and feed-back capabilities was developed in order to carry out the experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.17-24
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• 1999

This paper presents a method of ANC for transfonrer noise control utilizing a sproker and microphone pair. In this study, the main focus is on identifying the dynamic characteristics of speaker - amplifier microphone path. This study presents a theoretical method to identify the dynamic characteristics of speaker-microphone pairs. The transfer functions of microphone - speaker pair have been estimated utilizing sequential least square(SLS) algorithm. We identified the estimated transfer function has stable JXlles and zeros in z-plane. This paper also propose an architecture far the noise cancellation to which we applied the estimated transfer function.nction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.288-293
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• 2009

This study presents the active noise control of duct noise. The duct was excited by a steady-state harmonic and white noise force and the control was performed by one control speaker attached to surface of the duct. An adaptive controller based on filtered x LMS(FXLMS) algorithm was used and controller was defined by minimizing the square of the response of the error microphone. The assemble controller, which is called a hybrid ANC(active noise control) system, was combined with feedforward and feedback controller. The feedforward ANC attenuates primary noise that is correlated with the reference signal, while the feedback ANC cancels the narrowband components of the primary noise that are not observed by the reference sensor. Furthermore, in many ANC applications, the periodic components of noise are the most intense and the feedback ANC system has the effect of reducing the spectral peaks of the primary noise, thus easing the burden of the feedforward ANC filter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1528-1535
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• 1994

In this paper, a filtered-X LMS algorithm by new error path identification method is proposed for active noise control system. The proposed algorithm identifies accurately the error path transfer function using three microphones and the control of error signal through double loop scheme with on-line. In the computer simulation using the sinusoidal and the practical duct noise, the proposed algorithm reduces noise level about 29.1dB and 10.4dB, respectively. We can observe the improvement of about 0.5dB and 2.5dB in noise level compared with that obtained using the filtered-X LMS algorithm of Eriksson model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.284-292
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• 2008

The active control technique mostly uses the least-mean-square(LMS) algorithm, because the LMS algorithm can easily obtain the complex transfer function in real-time, particularly when the Filtered-X LMS(FXLMS) algorithm is applied to an active noise control(ANC) system. However, FXLMS algorithm has the demerit that stability of the control is decreased when the step size become larger but the convergence speed is faster because the step size of FXLMS algorithm is fixed. As a result, the system has higher probability which the divergence occurs. Thus the Co-FXLMS algorithm was developed to solve this problem. The Co-FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Co-FXLMS algorithm is presented in comparison with the FXLMS algorithm. Simulation and experimental results show that active noise control using Co-FXLMS is effective in reducing the noise in duct system.