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김의열,김병현,이상권 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.2
In this paper, an indirect feedback active noise control (ANC) scheme, based on the fundamental frequencyestimation method, is proposed for systems with multiple tonal noises. The engine noise consists of the harmonic components of the rotation of the crankshaft in the engine. When it is difficult to obtain reference signals, which are necessary for a feedforward ANC, conventional ANC algorithms do not work. In this paper, a new method is proposed to generate reference signals with estimated frequencies. The proposed algorithm consists of two parts: the frequency-estimation (FE) algorithm for the estimation of the fundamental frequency of the rotating machinery and then the conventional filtered-x LMS (FX-LMS)algorithm. In the second algorithm, the reference signal is generated using the fundamental frequency as estimated in the first algorithm. The FE algorithm uses a second-order adaptive notch filter, which is insensitive to impulse noise. In addition, the FE algorithm has good tracking capability and a lower variance of frequency-estimation error for a constant sinusoid signal and chirp signal. The performance of the proposed ANC method is verified through simulations and an experiment using a DSP board (DS-1104) inside a short duct.
고속 비행의 Lift-offset 복합형 헬리콥터 기체의 능동 진동 제어 시뮬레이션
홍성부,권영민,김지수,이유빈,박병현,신현철,박재상,Hong, Sung-Boo,Kwon, Young-Min,Kim, Ji-Su,Lee, Yu-Been,Park, Byeong-Hyeon,Shin, Hyun-Cheol,Park, Jae-Sang 한국군사과학기술학회 2021 한국군사과학기술학회지 Vol.24 No.4
This paper studies the simulations of active airframe vibration controls for the Sikorsky X2 helicopter with a lift-offset coaxial rotor. The 4P hub vibratory loads of the X2TD rotor are obtained from the previous work using a rotorcraft comprehensive analysis code, CAMRAD II. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics of the X2TD airframe and to analyze the 4P vibration responses of the airframe. A simulation study using Active Vibration Control System(AVCS) with Fx-LMS algorithm to reduce the airframe vibrations is conducted. The present AVCS is modeled using MATLAB Simulink. When AVCS is applied to the X2TD airframe at 250 knots, the 4P longitudinal and vertical vibration responses at the specified airframe positions, such as the pilot seat, co-pilot seat, engine deck, and prop gearbox, are reduced by 30.65 ~ 94.12 %.
홍성부,이예린,권영민,박재상,김지수,김도형 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.1
A simulation study using an active vibration control system (AVCS) to reduce airframe vibrations of an unmanned compound helicopter is conducted. The present unmanned compound helicopter uses wings, propellers, and a lift-offset coaxial rotor system, with two blades per rotor for high-speed flight. The airframe vibration responses are reduced using the AVCS at 230 knots. The hub vibratory loads of a lift-offset coaxial rotor are calculated using a rotorcraft comprehensive analysis code, CAMRAD II. The obtained rotor vibratory loads excite the airframe structure, represented as a one-dimensional stick (elastic line) model. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics and analyze the vibration response of the airframe. The AVCS in this work uses the Fx-LMS (Filtered-x Least Mean Square) algorithm to determine the vibration cancellation signal produced by the force generators, which has the same amplitude but opposite direction to the airframe vibration signal. Herein, the AVCS consists of four force generators and six accelerometers and the simulation framework is constructed using MATLAB Simulink. Ten AVCS simulations are conducted, considering the different locations and various directions of the vibration cancellation forces from the force generators. When AVCS is applied to the airframe at a flight speed of 230 knots, the 2/rev longitudinal and vertical vibration responses at the specified airframe positions, such as the remote cockpit device, wing root, and wing tip, are reduced by 81.39–99.93%, compared to the baseline results without AVCS application.
능동형 도로 소음 저감 기술의 Fx LMS 알고리즘 현장 적용 분석
강원평,문학룡,김솔람,이석기 한국도로학회 2016 한국도로학회 학술발표회 논문집 Vol.2016 No.06
도로교통 소음을 저감시키고자 하는 방안으로 가장 보편적인 방안으로 방음벽이 사용되어오고 있다. 하지만, 건물의 높이가 증가하여 방음벽의 높이도 높아지며, 이를 통한 주변경관을 저하가 되고 있다. 또 한, 방음벽의 높은 설치 및 유지비용도 방음벽의 한계로 작용하고 있다. 본 연구는 이러한 방음시설의 한 계를 극복하고자 능동형 소음 저감 기술(Active Noise Cancellation, 이하 ANC)이 대안으로 제시하였고, ANC 알고리즘 개발 및 현장 적용 분석을 진행하였다. ANC기술은 주로 음향장비, 차량내부 등 주로 내부 공간의 소음을 저감시키는데 사용된 기술이며, 도로 분야에 대한 적용은 기초적인 단계에 있다. 본 연구 에서는 가장 범용적인 ANC 알고리즘은 Fx LMS 알고리즘을 본 연구에서 개발한 ANC 제어기에 적용하여 현장 적용 분석을 수행하였다. 현장 적용은 경기도 광주 여주 IC 부근의 국도 구간과 중부내륙고속도로에 위치한 한국도로공사 시험도로에서 진행하였다. 현장 적용 결과 일반 국도에서는 일부 주파수 대역에서의 근소한 소음 저감 효과를 보였고, 고속도로의 경우 부분 주파수 대역에서 최대 3dB의 소음 저감을 보였다. 본 연구는 가장 범용적인 ANC 알고리즘은 Fx LMS 알고리즘을 통해 현장 적용 가능성을 입증 하였고, 향후, 다양한 ANC 알고리즘을 적용하여 현장적용에 적합한 알고리즘을 도출할 예정이다.
능동 진동 제어 시스템을 이용한 UH-60A 헬리콥터 기체의 진동 감소 시뮬레이션
이예린(Ye-Lin Lee),김도영(Do-Young Kim),김도형(Do-Hyung Kim),홍성부(Sung-Boo Hong),박재상(Jae-Sang Park) 한국항공우주학회 2020 韓國航空宇宙學會誌 Vol.48 No.6
대표적인 기동 헬리콥터인 UH-60A의 기체 진동응답을 감소시키고자 능동 진동 제어 시스템 (Active Vibration Control System, AVCS)을 이용한 시뮬레이션 연구를 수행하였다. 로터 진동 하중, 기체 구조 동역학 모델링, 진동응답 해석 및 진동 제어 시뮬레이션 연구를 수행하기 위하여 DYMORE II, NDARC, MSC.NASTRAN 및 MATLAB Simulink 등의 다양한 해석, 설계 및 제어 프로그램들을 함께 사용하였다. 5개의 CRFG와 7개의 가속도계로 이루어진 Multi Input Multi Output (MIMO) 모델을 AVCS 시뮬레이션 연구에 이용하였다. 본 시뮬레이션 연구를 통하여 진동이 극심한 158knots의 비행속도에서 UH-60A의 주요 위치(조종석, 로터와 기체의 접합부, 중앙 승객실 및 후방승객실) 위치에서 AVCS의 사용으로 인하여 4/rev 기체 진동응답이 25.14~96.05%만큼 감소될 수 있었다. This study using the active vibration control technique attempts to alleviate numerically the airframe vibration of a UH-60A helicopter. The AVCS(Active Vibration Control System) is applied to reduce the 4/rev vibration responses at the specified locations of the UH-60A airframe. The 4/rev hub vibratory loads of the UH-60A rotor is predicted using the nonlinear flexible dynamics analysis code, DYMORE II. Various tools such as NDARC, MSC.NASTRAN, and MATLAB Simulink are used for the AVCS simulation with five CRFGs and seven accelerometers. At a flight speed of 158knots, the predicted 4/rev hub vibratory loads of UH-60A rotor excite the airframe, and then the 4/rev vibration responses at the specified airframe positions such as the pilot seat, rotor-fuselage joint, mid-cabin, and aft-cabin are calculated without and with AVCS. The 4/rev vibration responses at all the locations and directions are reduced by from 25.14 to 96.05% when AVCS is used, as compared to the baseline results without AVCS.
Weijin Gao,Liang Wang,Yongguang Liu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.11
We determined the actuator location based on the dynamic modal of gear shaft, and analyzed the feasibility of a modified filtered-x least mean square algorithm with online secondary path identification. The proposed adaptive controller is designed to drive the actuators for preventing the vibration caused by gear backlash from a gear pair passing to the external gear housing structure. For the vital identification system, a changed identification input with error energy is presented to reduce the impact of additive random noise on the whole system. To ensure a realistic assessment of the proposed control strategy, numerical studies were implemented for a gearbox used by NASA-GRC. The simulation results validate the efficiency of the proposed approach through promising vibration control results that will guide future experimental work.