Co-FXLMS 알고리듬을 이용한 급가속시 자동차 흡기계의 능등소음제어

오재응(Jae-Eung Oh),이경태(Gyeong-Tae Lee),이해진(Hae-Jin Lee),방승우(Seung-Woo Bang),이정윤(Jung-Youn Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The method of the reduction of the automotive induction noise can be classified by the method of passive control and the method of active control. However, the passive control method has a demerit to reduce the effect of noise reduction at low frequency (below 500㎐) range and to be limited by a space of the engine room. Whereas, the active control method can overcome the demerit of passive control method. The algorithm of active control is mostly used the LMS (Least-Mean-Square) algorithm because the LMS algorithm can easily obtain the complex transfer function in real-time. Especially, When the Filtered-X LMS (FXLMS) algorithm is applied to an ANC system. However, the convergence performance of LMS algorithm goes bad when the FXLMS algorithm is applied to an active control of the induction noise under rapidly accelerated driving conditions. Thus Co-FXLMS algorithm was developed to improve the control performance under the rapid acceleration. 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 is presented in comparison with that of the FXLMS algorithm. Experimental results show that active noise control using Co-FXLMS is effective to reduce automotive induction noise under the rapid acceleration.

차량 능동 소음 제어 시스템에서 제어 위치 선택에 따른 소음 저감 성능에 관한 예비 평가

김성현,M. Ercan Altinsoy,김중관 한국소음진동공학회 2022 한국소음진동공학회 논문집 Vol.32 No.6

This study uses a modified cost function with weighted error signal channels to demonstrate that the vehicle active noise control system can focus control efforts on one specific seat. In a conventional active noise control system for road noise suppression inside a passenger car, the control algorithm targets the attenuation of all seats, hence affecting the maximum performance that can be obtained when applied to a single seat. To address this limitation, we employed weighting factors in the error signal to control the selected seat positions only. A practical active noise control system was implemented in a large sedan to investigate the effect of the weighting factor on the noise attenuation performance. Experimental results showed that the error weighting factor strategy increased attenuation of the target seats by up to 1.15dB more than in the case of the entire seat control.

열린 창문을 통해 유입되는 소음을 저감하는 능동소음제어 창문

권병호(Kwon, Byoung-Ho),박영진(Park, Young-Jin) 한국소음진동공학회 2011 한국소음진동공학회 논문집 Vol.21 No.9

Recently, noise has been regarded as one of the most notorious and frequent environmental pollutions which can be often encountered not only in the living space but also in the industrial site. Studies on physiological and psychological effects of long-term noise exposure to human being have commanded the public interest on noise issues. Since environmental noises such as traffic noise and construction noise is mainly flowed through the open window, it is necessary to develop the active noise control system to reduce it inside the building. Although control speakers and microphones for the noise signal measurement in the control region are essential for the conventional active noise control methods, it is impossible to implement them in the control region in the building environment because the control region is the living quarter and they may hinder activities of the residents. Therefore, we proposed the active window system to reduce the exterior noise flowed through the open window with microphones installed outside the window and control speakers installed at the frame of the window. To confirm the performance of the proposed active window, we carried out the simulation and experiment using active window system with 8 control speakers. Simulation results showed the noticeable noise reduction effect inside the control region within the frequency range without the spatial aliasing. Experimental result showed that the total acoustic potential energy inside the room of the scale model is reduced to about 10dB within the interest of frequency range.

선박 거주성 향상을 위한 선실 소음 저감 시스템 개발에 관한 실험적 연구

서영철,김득봉,김철승 해양환경안전학회 2023 해양환경안전학회지 Vol.29 No.6

선내 소음은 선원의 거주성과 건강을 위한 중요한 요소 중의 하나로, 선내 소음을 줄이기 위한 노력이 활발하게 진행되고 있다. 소음 저감 방법에는 수동소음제어(PNC) 방법과 능동소음제어(ANC) 방법이 있다. 자동차, 항공기와 달리 선박에서는 ANC를 이용한 소음 저감 대책이 미미한 실정이다. 본 연구는 능동소음제어(ANC)와 같이 방음판과 고주파진동원을 이용하여 기관실에 발생한 소음을 줄이고자 하였다. 이를 위해 아크릴 상자를 이용하여 실험 모형을 만들었고, 4가지 조건별로 소음 저감 효과를 측정하였다. 실험 결과는 다음과 같다. 첫째, 방음판은 55dB~85dB까지 모든 범위에서 소음 저감 효과가 있었다. 고주파진동원은 낮은 소음에서 효과가 없었으나, 70.8dB(A)과 85dB(A)와 같은 높은 소음에서는 효과가 있었다. 둘째, 방음판과 고주파진동원을 동시에 사용하는 경우에는 최대 -2.2dB(A) 만큼의 소음 저감 효과가 있었다. 본 실험의 결과는 아크릴판으로 제작한 실험모형에서 얻은 결과로 철판으로 된 실제 선박과 다를 수 있다. 추후 연구에서 실제 선박에서 사용하는 철판(재질과 두께, 구조를 고려)을 이용하여 실험하고자 한다. 이 연구가 선박에 승선하는 선원들의 거주성 향상과 건강 증진에 도움이 되기를 기대한다. Ship noise is one of the important factors for the living and health of seafarers, and efforts to reduce ship noise are actively underway. There are two methods of noise reduction: passive noise Control (PNC) and active noise control (ANC). Unlike cars and airplanes, ANC is not widely used for noise reduction on ships. This study aimed to reduce the noise generated in the engine room by using soundproof panels and high-frequency vibration generators, as well as active noise control (ANC). For this purpose, an experimental model was made using an acrylic box, and the noise reduction effect was measured under four conditions. The experimental results are as follows: First, the soundproof panel had a noise reduction effect in all ranges from 55dB to 85dB. In the case of using a high-frequency vibration generator, there was no effect in the low noise range such as 55dB(A), but there was a noise reduction effect in the high noise range such as 70.8dB(A) and 85dB(A).Second, when the soundproof panel and the high-frequency vibration generator were used simultaneously, the noise reduction effect was up to -2.2dB(A). The results of this experiment were obtained from an experimental model made of acrylic, and they may be different from actual ships made of steel plate. In future studies, we plan to experiment using iron plate (considering the material, thickness, and structure) used in actual ships. We hope that this study will help to improve the living environment and health of seafarers on ships.

능동 탭 로터 모델링 및 BVI 소음 저감 특성 해석

김도형(Do-Hyung Kim),강희정(Hee Jung Kang),위성용(Seong-Yong Wie),김승호(Seung-Ho Kim) 한국항공우주학회 2013 韓國航空宇宙學會誌 Vol.41 No.11

능동 탭은 BVI 소음 저감을 위한 능동제어 기술 중 하나이며, 이를 이용한 소음 저감효과에 대한 해석은 기술 개발에 있어서 매우 중요한 과정의 하나이다. 능동 탭의 소음저감 성능 분석을 위하여 모델 로터시스템에 대한 구조 설계를 수행하고 CFD 해석을 통해 에어포일 공력 데이터를 생성하였으며, 이를 이용하여 통합해석 프로그램인 CAMRAD Ⅱ 모델을 구성하였다. 하강 비행 상태에서 능동 탭을 HHC 방법으로 작동할 경우 로터에서 발생되는 공력 하중을 CAMRAD Ⅱ를 이용하여 계산하고, 이에 따른 BVI 소음 변화를 자체 소음해석 프로그램으로 계산하였다. 능동 탭의 작동 길이 및 제어 위상의 변화에 따른 소음해석 결과 최대 -3.3㏈의 BVI 소음 저감 효과를 얻을 수 있었다. Active tab is one of the promising technology for the BVI (blade-vortex interaction) noise reduction, and analysis of noise reduction performance is very important phase of the technology development. For the purpose of analysing the performance of noise reduction using active tab, CAMRAD Ⅱ model for a model-scale rotor system was constructed utilizing structural design result and airfoil aerodynamic data generated by CFD (computational fluid dynamics) calculation. HHC strategy was applied to descent flight condition and air-load was calculated by CAMRAD Ⅱ then variations of BVI noise was calculated by in-house program. Calculation result with respect to tab length and control phase changes showed BVI noise could be reduced by -3.3㏈.

단일 센서 방식의 적응 능동 소음제어

김영달,장석구 한국소음진동공학회 2000 소음 진동 Vol.10 No.6

Active noise control is an approach to reduce the noise by utilizing a secondary noise source that destructively interferes with the unwanted noise. In general, active noise control systems rely on multiple sensors to measure the unwanted noise field and the effect of the cancellation. This paper develops an approach that utilizes a single sensor. The noise field is modeled as a stochastic process, and an adaptive algorithm is used to adaptively estimate the parameters of the process. Based on these parameter estimates, a canceling signal is generated. Oppenheim assumed that transfer function characteristics from the canceling source to the error sensor is only a propagation delay. This paper proposes a modified Oppenheim algorithm by considering transfer characteristics of speaker-path-sensor This transfer characteristics is adaptively cancelled by the proposed adaptive modeling technique. Feasibility of the proposed method is proved by computer simulations with artificially generated random noises and sine wave noise. The details of the proposed architecture. and theoretical simulation of the noise cancellation system for three dimension enclosure are presented in the Paper.

기계실 압축기 소음의 능동 제어를 위한 제어기 설계

구정모(Jung-Mo Koo),홍진숙(Chinsuk Hong),정의봉(Weui-Bong Jeong),배승훈,김태훈(Tae-Hoon Kim) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.4

The active control of noise generated by the compressor and transmitted out of the machine room through the windows is implemented based on the FIR filter. The machine room contains most of noise sources of electric home appliances, air-conditioners and refrigerators, for example. To actively reduce the noise from the machinery room. In this paper, the transfer function of the controller for minimization of the acoustic power transmitted through the windows is mathematically formulated. The transfer functions required for implementation of the active controller are the measured. The measurements are conducted in this initial stage under the operation of the compressor with no load. For improvement of the reliability of the transfer function of the compressor to the acoustic power, additional operational measurements are performed. The real time controller is implemented based on the FIR filter using the measured transfer functions and the performance of the active controller is estimated.

능동 탭을 이용한 로터시스템 BVI 소음 저감

김도형,강희정,위성용,김승호 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11

능동 탭은 로터시스템의 소음저감을 위해 적용 가능한 기술 중 하나이다. 이러한 기술의 적용에 따른 로터시스템의 동적 거동 변화와 소음 저감 효과에 대한 해석은 기술 개발 과정에 있어 매우 중요한 업무이다. 통합해석 프로그램을 이용한 능동 탭 로터시스템의 해석을 수행하기 위해서 2차원 CFD 해석으로 탭을 가지는 에어포일에 대한 공력 데이터를 생성하여 이용하였다. BVI 소음이 크게 발생되는 상태에서 능동 탭을 작동할 경우 블레이드의 탄성 변형과 공력하중을 계산하였으며, 이를 이용한 소음해석 결과 최대 -3.3 dB의 BVI 소음저감 효과가 관찰되었다. Active tab is one of the applicable technologies for the noise reduction of helicopter rotor system. The analysis about the changes of dynamic responses and the effects on the noise reduction is very important activity of the technology development. In order to prepare comprehensive analysis of the rotor system with active tab, 2D CFD analysis was performed to generate airfoil aerodynamic data of an airfoil with tab configuration. The blade elastic deformations and air-loads were calculated for flight condition which makes maximum BVI (blade vortex interaction), then noise was calculated using the calculated air-load. It showed that BVI noise could be reduced by -3.3 dB.

FXLMS 알고리듬을 이용한 덕트의 능동소음제어

류경완(Ryu, Kyung-Wan),홍진숙(Hong, Chin-Suk),정의봉(Jeong, Wei-Bong) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.1

This paper investigates active noise control of ducts using filtered-x least mean square(FXLMS) algorithms to reduce noise transmission. Single channel FXLMS(SFXLSM) and multiple channel FXLMS(MFXLMS) algorithms are used to implement the active control systems. The transmission loss is significantly increased by SFXLMS but the sound pressure level(SPL) at the upstream of the error sensor is increased while that of downstream is very low. This increase of the upstream SPL causes the duct wall to vibrate and so to radiate noise. To prevent the wall vibration generated by the sound field upstream, global sound field control is required. To reduce SPL globally along the duct, active noise control using MFXLMS is implemented. We can then be obtained globally reduced SPL. It is found experimentally that the vibration level, and so the radiated noise level, can be reduced by the active noise control using MFXLMS.

음원을 둘러싼 인클로저 개구부를 통해 투과되는 소음의 능동 제어

이한울(Hanwool Lee),홍진숙(Chinsuk Hong),정의봉(Weuibong Jeong) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.4

In this study, we investigates active control technology to reduce the noise transmitted to the outside through the opening of enclosures. A numerical model based on acoustic boundary element method is first established. Using the numerical model, the acoustic transfer functions of the field points over the opening to the primary source at arbitrary locations are estimated. The feedforward control to minimize the acoustic power through the opening is then numerically implemented. The controller generates the secondary source to destructively interfere the noise transmission through the opening. Finally, a parametric study is conducted to evaluate the effects of the location and the number of the microphones on the control performance. Furthermore, the effects of the location of the secondary source on the performance of active noise control are investigated. It is followed that the control system implemented in this study leads to a significant reduction of about 35dB in sound power through the open using only on secondary source located at the optimized position.