• International Journal of Precision Engineering and Manufacturing
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• 제6권4호
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• pp.37-43
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• 2005

This paper presents a hybrid control algorithm for the active noise control in the rectangular enclosure using an active/passive foam actuator. The hybrid control composes of the adaptive feedforward with feedback loop in which the adaptive feedforward control uses the well-known filtered-x LMS(least mean square) algorithm and the feedback loop consists of the sliding mode controller and observer. The hybrid control has its robustness for both transient and persistent external disturbances and increases the convergence speed due to the reduced variance of the jiltered-x signal by adding the feedback loop. The sliding mode control (SMC) is used to incorporate insensitivity to parameter variations and rejection of disturbances and the observer is used to get the state information in the controller deign. An active/passive smart foam actuator is used to minimize noise actively using an embedded PVDF film driven by an electrical input and passively using an absorption-foam. The error path dynamics is experimentally identified in the form of the auto-regressive and moving-average using the frequency domain identification technique. Experimental results demonstrate the effectiveness of the hybrid control and the feasibility of the smart foam actuator.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.255-260
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• 1988

A robust adaptive control method for a stable nonminimum phase SISO system with unmodelled dynamics is proposed. The robust parameter estimation method of the system with bounded output noise and unmodelled dynamics is employed and a parallel structure is proposed to improve the robustness of adaptive control system. The local stability of the proposed system is shown. Computer simulations are done in order to compare the performance of the proposed structure with the basic structure on various circumstance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.283-287
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• 1996

The exhaust noise reduction of automobile with the active muffler is experimentally investigated. The control algorithm is the filtered-x LMS algorithm and the inverse algorithm with the adaptive line enhancer. Also, the control efficiency is increased with synthesized second harmonic engine frequency. In the experiment, the active muffler is applied to the end of exhaust system in automobile and the control with on-line secondary path modeling method(inverse algorithm) is compared the control of off-line secondary path modeling method. As secondary path transfer functions are changed, the experimental results show that the control performance with on-line method is more efficient than that with off-line method in the exhaust noise reduction of automobile.

• The Journal of the Acoustical Society of Korea
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• 제11권1E호
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• pp.56-63
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• 1992

The poblem of active oise control has been analysed using a adaptive signal processing technique. In this methods, the adaptive signal processor or model predicts the primary sound wave travelling along the acoustic plant and generates the secondary source 180° out of phase which attempts to attempts to attenuate the undesired noise by destructive interference. In the solutions presented here, acoustic propagation delay is considered as a part of the model which used the FIR filter. The effects of error path and auxiliary path transfer functioin are anayzed and a new on=-line technique for error path modeling, adaptive delayed inverse modeling is presented. In this study, using these new concepts, our system can more reduce the noise level in duct to 5dB-15dB than only using LMS algorithm system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.238-239
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• 2008

In this paper, active noise control (ANC) of a Volterra system with a nonlinear secondary path is proposed in the presence of a linear acoustic feedback, whereby the conventional ANC of a linear system with online acoustic feedback-path modeling is further extended to ANC of a Volterra system with a linear acoustic feedback path. In particular, the proposed ANC system consists of two adaptive Volterra filters (for nonlinear noise control and nonlinear adaptive noise cancellation) and one feedback-path modeling filter. Simulation results show that the proposed approach yields more effective reduction of disturbances arising from the acoustic feedback, in addition to high nonlinear ANC performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.489-496
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• 2008

This paper investigates active noise control of ducts using Filtered-x Least Mean Square (FXLMS) algorithms to reduce noise transmission. Single channel FXLMS (MFXLSM) 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 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.

• 한국소음진동공학회논문집
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• 제19권1호
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• pp.24-34
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• 2009

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.

• 조명전기설비학회논문지
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• 제14권1호
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• pp.94-101
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• 2000

본 논문에서는 서브밴드 기법을 이용한 다중채널 능동소음제어 알고리즘을 제안하였다. 제안된 서브밴드 제어 기법은 3차원 폐공간에서의 능동소음제어서 가장 문제가 되는 계산량을 줄이고 성능올 향상시키기 위한 방법으로, 소음신호를 여러 개의 주파수 밴드로 분할하여 병렬 처리함으로서 원하는 주파수 범위의 소음을 효과적으로 제거할 수 있어 기존의 알고리즘 보다 낮은 차수의 적웅필터를 사용할 수 있다. 적용필터 알고리즘으로 서브밴드로 나펀 기준입력 대신에 오차신호를 perfiltering하는 adjoint LMS 알고리즘을 적용하여 전체적인 계산량의 감소를 이룰 수 있었으며, 성능 향상올 위하여 기존의 하이브리드 제어기법을 변형하여 전향제어기와 궤환제어기의 특성을 가중적으로 갖는 하이브리드 제어기법올 광대역 소음제어 시스템에 적용하여 우수한 소음제거특성과 시스템의 높은 안정성올 얻었다. 제안된 알고리즘의 성능을 평가하기 위해서 컴퓨터 시뮬레이션을 통해 기존의 알고리즘과 비교하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.667-673
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• 2000

A number of issues related with the vibrational behavior of pretwisted rotating beams featuring anisotropic properties and incorporating adaptive capabilities are considered in this paper. The adaptive capabilities are provided by a system of piezoactuators bonded or embedded into the structure. Based on the converse piezoelectric effect and on the out of phase activation, boundary control moments are pizoelectrically induced at the beam tip. A feedback control law relating the induced bending moments with the kinematical response quantities appropriately selected is used, and its beneficial effects, considered in conjunction with that of the beam anisotropy and structural pretwist upon the eigenvibration characteristics are highlighted

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1992년도 추계학술발표회논문집
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• pp.56-59
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• 1992

Adaptive active attenuation of noise in a duct is considered. A duct is modelled when the acoustic feedback exists. The secondary path transfer function is estimated using multiple model approaches. An IIR structure is assumed for the control filter, and the recursive least mean squares algorithm is used to adjust the filter coefficients.