• Title, Summary, Keyword: semiactive control

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Cable vibration control with a semiactive MR damper-numerical simulation and experimental verification

  • Wu, W.J.;Cai, C.S.
    • Structural Engineering and Mechanics
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    • v.34 no.5
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    • pp.611-623
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    • 2010
  • Excessive stay cable vibrations can cause severe problems for cable-stayed bridges. In this paper a semiactive Magnetorheological (MR) damper is investigated to reduce cable vibrations. The control-oriented cable-damper model is first established; a computer simulation for the cable-damper system is carried out; and finally a MR damper is experimentally used to reduce the cable vibration in a laboratory environment using a semiactive control algorithm. Both the simulation and experimental results show that the semiactive MR damper achieves better control results than the corresponding passive damper.

State-of-the-art of semiactive control systems using MR fluid dampers in civil engineering applications

  • Jung, H.J.;Spencer, B.F. Jr.;Ni, Y.Q.;Lee, I.W.
    • Structural Engineering and Mechanics
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    • v.17 no.3_4
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    • pp.493-526
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    • 2004
  • Semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds, because they not only offer the reliability of passive control systems but also maintain the versatility and adaptability of fully active control systems. Among the many semiactive control devices, magnetorheological (MR) fluid dampers comprise one particularly promising class. In the field of civil engineering, much research and development on MR fluid damper-based control systems has been conducted since this unique semiactive device was first introduced to civil engineering applications in mid 1990s. In 2001, MR fluid dampers were applied to the full-scale in-service civil engineering structures for the first time. This state-of-the-art paper includes a detailed literature review of dynamic models of MR fluid dampers for describing their complex dynamic behavior and control algorithms considering the characteristics of MR fluid dampers. This extensive review provides references to semiactive control systems using MR fluid dampers. The MR fluid damper-based semiactive control systems are shown to have the potential for mitigating the responses of full-scale civil engineering structures under natural hazards.

Structural Vibration Control Using Semiactive Tuned Mass Damper (건물의 내진성능을 향상시키기 위한 반능동 동조질량감쇠 시스템)

  • Moon, Yeong-Jong;Ji, Han-Rok;Jung, Hyung-Jo;Lee, In-Won
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.645-650
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    • 2006
  • This paper presents the results of a study to verify the sufficient control performance of semiactive tuned mass damper and to identify suitable control methods for semiactive tuned mass damper in structural vibration control. In this study, four control algorithms are considered: on-off displacement based groundhook, on-off velocity based groundhook, clipped optimal and maximum energy dissipation algorithm. For semiactive tuned mass damper, MR damper is considered as a controllable damping device and the command voltage is calculated by the control algorithms. Each of the control theory is applied to the three story shear building excited by three earthquakes. The performance of each algorithm is compared with that of conventional tuned mass damper system using evaluation criteria. The simulation results indicate that semiactive tuned mass damper has control efficiency. Among the control algorithms, on-off displacement based control theory shows the best efficacy and robustness.

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Semiactive Control Systems Using MR Fluid Dampers in Civil Engineering Applications: a State-of-the Art Review (토목공학에서의 자기유변 유체 감쇠기를 이용한 반능동 제어 시스템: 최신 연구 동향)

  • 정형조;박규식;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.467-474
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    • 2002
  • Semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds, because they not only offer the reliability of passive control systems but also maintain the versatility and adaptability of fully active control systems. Among the many semiactive control devices, magnetorheological (MR) fluid dampers comprise one particularly promising class. In the field of civil engineering, much research and development on MR fluid damper-based control systems has been conducted since B. F. Spencer first introduced this unique semiactive device to civil engineering applications in mid 1990s. In 2001, MR fluid dampers were applied to the full-scale in-service civil engineering structures for the first time. This state-of-the-art paper includes a detailed literature review of control algorithms considering the characteristics of fm fluid dampers. This review provides references to semiactive control systems using MR fluid dampers. The MR fluid damper-based semiactive control systems are shown to have the potential for mitigating the responses of full-scale civil engineering structures under natural hazards.

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Modeling and Control of a Hydraulic Semiactive Vibration Absorber (유압식 반능동 진동 흡수기의 모델링과 제어)

  • 모창기
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.700-705
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    • 1998
  • Recent past work has demonstrated that hydraulic semiactive vibration absorbers hold the promise of providing an ideal means of mitigating structural vibration. This paper examines a factor that must be treated when designing a hydraulic semiactive vibration absorber for application to a full scale structure; fluid compressibility. An expanded and consistent dynamic model of the flow process is first established. A simple feedback control is then tested on a single degree of freedom laboratory structure to verify the findings.

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Vibration Control of Stay Cables Using Semiactive Control System (반능동 제어 시스템을 이용한 사장케이블의 진동제어)

  • 장지은;정형조;윤우현;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.57-64
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    • 2004
  • Stay cables, such as are used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. Several methods have been proposed and implemented to mitigate this problem, though each has its limitations. Recently some studies have shown that semiactive dampers can potentially achieve performance levels nearly the same as comparable active devices with few of the detractions. This paper presents the results of a study to evaluate the performance of semiactive dampers for mitigating the vibration of stay cables. Moreover, a number of recently proposed semiactive control algorithms are formulated for use with shear mode MR damper to compare the efficiency of each algorithm through numerical simulation. Numerical simulation considers a stay cable excited by shaker and controlled by shear mode MR dampers. In simulation, the response with a semiactive damper is found to be dramatically reduced compared to the uncontrolled case. Furthermore, it is verified that the algorithm based on Lyapunov control theory is very efficient in mitigating the cable vibration.

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Semiactive Neuro-control for Seismically Excited Structure considering Dynamics of MR Damper (자기유변유체감쇠기의 동특성을 고려한 지진하중을 받는 구조물의 반능동 신경망제어)

  • 이헌재;정형조;오주원;이인원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.473-480
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    • 2003
  • A new semiactive control strategy for seismic response reduction using a neuro-controller and a magnetorheological (MR) fluid damper is proposed. The proposed control system adopts a clipped algorithm which induces the MR damper to generate approximately the desired force. The improved neuro-controller, which was developed by employing the training algorithm based on a cost function and the sensitivity evaluation algorithm replacing an emulator neural network, produces the desired active control force, and then by using the clipped algorithm the appropriate command voltage is selected in order to cause the MR damper to generate the desired control force. The simulation results show that the proposed semiactive neuro-control algorithm is quite effective to reduce seismic responses. In addition, the semiactive control system using MR fluid dampers has many attractive features, such as bounded-input, bounded-output stability and small energy requirements. The results of this investigation, therefore, indicate that the proposed semiactive neuro-control strategy using MR fluid dampers could be effective used for control seismically excited structures.

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Semiactive Control for Structural Vibration Mitigation (구조물 진동 저감을 위한 반능동 제어)

  • Changki Mo;Jaesoo Lee
    • Journal of KSNVE
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    • v.11 no.1
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    • pp.96-103
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    • 2001
  • Past research has repeatedly demonstrated the fact that hydraulic semiactive systems, if operated Properly, can provide levels of control authority in structural vibration control systems that are comparable to a fully active hydraulic damper. The performance of the semiactive system when used to provide vibration mitigation for a laboratory test structure is described in this paper Numerical and experimental verification of the effectiveness of the proposed bistate controller which relies on a Lyapunov approach that seeks to dissipate the energy of the system is also presented. The results based on the bistate control are compared with those of two different control strategies. The work indicates that hydraulic semiactive actuator provides a reliable, and inexpensive means of achieving structural control.

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Practical Semiactive Control of Hydropnematic Suspension Units (유기압 현수장치의 반능동 제어 구현에 관한 연구)

  • 이윤복;송오섭
    • Journal of the Korea Institute of Military Science and Technology
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    • v.6 no.4
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    • pp.9-21
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    • 2003
  • This paper describes the practical implementation of a semiactive hydropneumatic suspension system to provide the high off-road performance of military tracked vehicles. Real gas behavior of a spring system, frictional forces of joints, and the dynamics of a continuously variable damper are considered. The control system is consisted of two control loops, an outer loop calculates a target spool position which can deliver the required damping force and an inner loop tracks the required spool position. Dynamic tests of the one axis model show that the semiactive suspension system considerably reduces the acceleration as well as velocity and displacement of the sprung mass than the passive one.

Application of Some Semiactive Control Algorithms to a Smart Base Isolated Building Employing MR Dampers (MR감쇠기가 설치된 지진격리 건물의 스마트 진동제어)

  • Jung, Hyung-Jo;Choi, Kang-Min;Jang, Ji-Eun;Lee, In-Won
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.544-551
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    • 2005
  • This paper investigates the effectiveness of the MR damper-based control systems for seismic protection of base isolated building sturcutres employing some semiactive control algorithms, such as the modified clipped-optimal control, the maximum energy dissipation, and the modulated homogeneous friction, by examining the Phase I smart base isolated benchmark building problem. The results of the numerical simulations showed that most of the control systems considered herein could be beneficial in reducing seismic responses, especially base displacement or isolator deformation, of base isolated building structures. It is also verified that another version of the modified clipped-optimal control algorithm proposed in this study and the modulated homogeneous friction algorithm are more effective than other semiactive control algorithms.

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