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이충휘(Choong-Hwi Lee),조용구(Joe Yong-Goo),이유엽(You-Yub Lee),오재응(Jae-Eung Oh),이정윤(Jung Youn Lee) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The method of the reduction of the 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 500Hz) 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, 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. So, this study demonstrates the modified FXLMS algorithm and improves the control performance to reduce the automotive induction noise under the rapidly accelerated driving conditions.
능동제어방식을 이용한 자동차의 흡기소음 제어성능 향상에 관한 연구
오재응(Jae-Eung Oh),이충휘(Choong-Hwi Lee),이정윤(Jung Youn Lee) 한국자동차공학회 2002 한국자동차공학회 Symposium Vol.2002 No.11
The one of the conventional method to reduce the automotive intake noise is the addition of the resonator to the<br/> intake system. However, the Active Noise Control (ANC) method was proposed as a new method to reduce the<br/> intake noise because it is difficult to install many resonators in the engine room. ANC method uses the interference<br/> between the sound generated by the primary source and the sound due to the secondary source of the same<br/> frequency and amplitude but opposite phase. A Filtered-x LMS algorithm, one of the forms of the least mean square<br/> (LMS) algorithm which is mostly used in the adaptive noise control systems, was used as control algorithm.<br/> However, under condition of rapid and sudden acceleration, the intake noise reduction by Filtered-x LMS algorithm<br/> is not effective. So, this study demonstrates the modified Filtered-x LMS algorithm and improves the control<br/> performance to reduce the automotive intake noise under the rapid and sudden acceleration.
2 자유도계 모델을 이용한 디스크 브레이크의 면외방향 운동에 대한 접촉강성의 영향
조용구(Yong-Goo),신기흥(Ki-Hong Shin),차병규(Byung-Gyu Cha),이충휘(Choong-Hwi Lee),이정윤(Jung-Yoon Lee),오재웅(Jae-Eung Oh) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A two degree-of-freedom mathematical model is presented to investigate the friction mechanism of a disc brake system. A contact parameter is introduced to describe the coupling between the in-plane and the out-of-plane motions. In order to describe the relationship between the in-plane motion and the out-of plane motion, the contact friction coefficient is considered as a function of both relative velocity and normal force. The out-of-plane motion is then investigated by numerical analysis for various parametric conditions. The results of numerical analysis show the existence of limit cycle of an out-of-plane motion caused by the effect of intermittent contact stiffness. Also Frequency analysis shows that the motion due to the contact nonlinearity produces frequency unification and frequency modulation.