• Title/Summary/Keyword: ActiveX control

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Intelligent hybrid controlled structures with soil-structure interaction

  • Zhang, X.Z.;Cheng, F.Y.;Lou, M.L.
    • Structural Engineering and Mechanics
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    • v.17 no.3_4
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    • pp.573-591
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    • 2004
  • A hybrid control system is presented for seismic-resistant building structures with and without soil-structure interaction (SSI). The hybrid control is a damper-actuator-bracing control system composed of passive and active controllers. An intelligent algorithm is developed for the hybrid system, in which the passive damper is designed for minor and moderate earthquakes and the active control is designed to activate when the structural response is greater than a given threshold quantity. Thus, the external energy for active controller can be optimally utilized. In the control of a multistory building, the controller placement is determined by evaluating the optimal location index (OLI) calculated from six earthquake sources. In the study, the soil-structure interaction is considered both in frequency domain and time domain analyses. It is found that the interaction can significantly affect the control effectiveness. In the hybrid control algorithm with intelligent strategy, the working stages of passive and active controllers can be different for a building with and without considering SSI. Thus SSI is essential to be included in predicting the response history of a controlled structure.

Filtered-x LMS Algorithm for noise and vibration control system (잡음 및 진동제어시스템을 위한 Filtered -x LMS 알고리즘)

  • kim, soo-yong;Jee, suk-kun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.697-702
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    • 2009
  • Filtered-x LMS algorithm maybe the most popular control algorithm used in DSP implementations of active noise and vibration control system. The algorithm converges on a timescale comparable to the response time of the system to be controlled, and is found to be very robust. If the pure tone reference signal is synchronously sampled, it is found that the behavior of the adaptive system can be completely described by a matrix of linear, time invariant, transfer functions. This is used to explain the behavior observed in simulations of a simplified single input, single output adaptive system, which retains many of the properties of the multichannel algorithm.

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Improvement of active nose control in vehicle interior using a RLS algorithm (RLS 알고리즘을 이용한 승용차 내 능동소음제어의 개선)

  • 김영욱;이윤희;김기두
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.12
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    • pp.106-113
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    • 1997
  • While driving, the low frequency interior noise below 200Hz causes the main component that irritates the auditory acoustic sense. But these passive control methods bring out increment in cost and weight of the vehicle and result in low efficiency. Recently, various ANC(Active Noise Control) methos to suppress the low frequency noise began to launch into application. In this study, we implemented the active noise control system for passenger vehicle to cancel the engine booming noise using DSP-based control unit, 4 micorphones, and 2 speakers. We used MEFX-LMS (Multiple Error Filtered X-Least Mean Square) algorithm since it can be easily implemented in real time. Also, MEFX-RLS algorithm was taken to enhance the suppression of the harmonic components of the engine booming noise inspite of its computational complexity. The performance of two adaptive algorithms were analyzed with experimental resutls.

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Characteristin Analysis of UPS Fan Noise Reduction by Multiple-Referedce/Multiple-Output FXLMS Algorithm (다중-레퍼런스/다중-출력 FXLMS 알고리즘에 의한 UPS 팬 소음저감 특성해석)

  • 이승요;조준석;최규하
    • The Transactions of the Korean Institute of Power Electronics
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    • v.4 no.6
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    • pp.589-600
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    • 1999
  • Audible noise of UPS(uninterruptible power supply) with small rated [Xlwer is usually generattxl by the c cooling fan‘ For active noise control for radiated noise of UPS, it is adequate to apply multiple-channel F FXLMS algorithm based on Filten어 x LM~longrightarrow algorithm. In this paper, to reduce the audible noise of UPS‘ Its m noise characteristics of UPS are an띠yzed and active noise control by using 이ffiMOClVlultiple- Reference/ M Multiple-Output) FXLMS algorithm is perf‘onned. Also, noise reduction characteristics are shown by computer S simulation and experimental results.

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Active control of a flexible structure with time delay

  • Cai, Guo-Ping;Yang, Simon X.
    • Structural Engineering and Mechanics
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    • v.20 no.2
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    • pp.191-207
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    • 2005
  • Time delay exists inevitably in active control, which may not only degrade the system performance but also render instability to the dynamic system. In this paper, a novel active controller is developed to solve the time delay problem in flexible structures. By using the independent modal space control method, the differential equation of the controlled mode with time delay is obtained from the time-delay system dynamics. Then it is discretized and changed into a first-order difference equation without any explicit time delay by augmenting the state variables. The modal controller is derived based on the augmented system using the discrete variable structure control method. The switching surface is determined by minimizing a discrete quadratic performance index. The modal coordinate is extracted from sensor measurements and the actuator control force is converted from the modal one. Since the time delay is explicitly included throughout the entire controller design without any approximation, the system performance and stability are guaranteed. Numerical simulations show that the proposed controller is feasible and effective in active vibration control of dynamic systems with time delay. If the time delay is not explicitly included in the controller design, instability may occur.

A Study on Enforcement Effects of Radiation Safety Control Regulations for Diagnostic X-ray Equipments (진단용 방사선안전관리 현황에 관한 연구)

  • Sung, Mo-Il;Park, Myeong-Hwan;Kwon, Duk-Moon;Lee, Joon-Il
    • Journal of radiological science and technology
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    • v.22 no.1
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    • pp.73-78
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    • 1999
  • The purposes of this study are to analyze the realities after enforcements of safety control regulations for diagnostic X-ray equipments and to suggest means for an improvement of low radiation safety control. A questionnaire survey for medical radiologic technologists was carried out to determine enforcement effects of the safety control regulations. The results of analysis from the survey are as follows. That is, most of the respondents realized the importance of the radiation safety control system, but about a half of them revealed that the regulations were not well observed in accordance with their purposes. Only 43.9% of the respondents took an active part in quality control and safety control of radiation. And respondents responsibility, sex, age, and knowledge for safety control were important indicators for observations of the regulations. Trainings for the safety control regulations are needed to ensure safety control and proper usage of diagnostic X-ray equipments. And management of organizations using diagnostic X-ray equipments have to understand and stress the importance of radiation safety control system.

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Exhaust Noise Control with the Active Muffler in Exhaust System of Vehicle (상용차 배기계에서 액티브 머플러를 이용한 배기 소음 제어)

  • 김홍섭;홍진석;오재응;송진호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.36-42
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    • 1998
  • In this study, active muffler was designed and was manufactured for exhaust noise reduction of commercial vehicle, then experiment of real vehicle was conducted. In a manufactured active muffler, because the flow of exhaust noise in tail pope outlet are become a plane wave, the global reduction if radiation noise from outlet and the placement of error microphone to avoid the exhaust gas of high temperature could be implemented. In control algorithm, reduction of noise of engine driving frequency and harmonic frequency can be archieved using proposed reference signal including a fixed speed state(2,000rpm, 3,000rpm, 4,000rpm) and a run-up speed state(2,000rpm$\rightarrow$4,000rpm) is accomplished with the active muffler installed in vehicle.

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A Study on the Active Noise Cancellation System in a Vehicle Cabin Using the Weighting Factors of Control Error Path (제어오차계의 가중치를 이용한 차실내 능동소음제어 시스템 연구)

  • 홍석윤;허현무
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.851-856
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    • 1996
  • The active noise cancellation system showing the effective convergence and stability has been studied by simplifying the controller structures using the weighting factors of control error path to the multi-channel filtered-x LMS algorithm which needs a lot of calculations and the performance has been verified experimentally. Besides, to implement the system performance in a vehicle cabin, experimental work for selecting the suitable numbers and positions of the microphones and speakers was accomplished. Effectively combining a TMS 320C 31 main processor conducting real number calculations and having various functions with other components, the purpose-built system board for active noise cancellation has been designed and with this board, car active noise cancellation system showing maximum stable 10dB noise reduction has been obtained at the car idling conditions above 3000rpm range.

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Performance Improvement of the Active Noise Control System Using RCMAC and PSO Method (RCMAC 및 PSO 기법을 이용한 능동 소음제어 시스템 성능 개선)

  • Han, Seong-Ik;Shin, Jong-Min;Kim, Sae-Han;Lee, Kwon-Soon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1900-1907
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    • 2010
  • In this paper, a recurrent cerebellar modulation articulation control with praticle swarm optimization (PSO) method has been investigated for improvement of noise attenuation performance in active noise control system. For narrow band noise, FXLMS and RCMAC has a partial satisfactory noise attenuation. However, noise attenuation performance is poor for broad band noise and nonlinear path since it has linear filter structure. To improve this problem, a RCMAC with PSO is proposed and it is shown that satisfactory noise attenuation performance is obtained by some simulations in duct system using harmonic motor noise and KTX cabin noise as a noise source.

Acitve Noise Control via Walsh Transform Domain Genetic Algorithm (월쉬변환영역 유전자 알고리즘에 의한 능동소음제어)

  • Yim, Kook-Hyun;Kim, Jong-Boo;Ahn, Doo-Soo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.11
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    • pp.610-616
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    • 2000
  • This paper presents an active noise control algorithm via Walsh transform domain controller learned by genetic algorithm. Typical active noise control algorithms such as the filtered-x lms algorithm are based on the gradient algorithm. Gradient algorithm have two major problems; local minima and eigenvalue ratio. To solve these problems, we propose a combined algorithm which consist of genetic learning algorithm and discrete Walsh transform called Walsh Transform Domain Genetic Algorithm(WTDGA). Analyses and computer simulations on the effect of Walsh transform to the genetic algorithm are performed. The results show that WTDGA increase convergence speed and reduce steady state errors.

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