• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.21-29
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• 2006

It is impractical to install sensors on every floor of a tall building to measure the full state vector because of the large number of degrees of freedom. This makes it necessary to introduce reduced order control. A kind of system reduction scheme (dynamic condensation method) is proposed in this paper. This method is iterative and Guyan condensation is looked upon as an initial approximation of the iteration. Since the reduced order system is updated repeatedly until a desired one is obtained, the accuracy of the reduced order system resulting from the proposed method is much higher than that obtained from the Guyan condensation method. An eigenvalue shilling technique is applied to accelerate the convergence of Iteration. Two schemes to establish the reduced order system by using the proposed method are also presented and discussed in this paper. The results for a tail building with active tuned mass damper show that the proposed method is efficient for the reduced order modelling and the accuracy is very close to exact only after two iterations.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.1
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• pp.53-61
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• 2001

구조물이 과동한 기진력을 받을 때에 구조물의 진동 제어를 위하여 적응형 뱅뱅 제어 알고리듬이 저자들에 의해서 제안된 바 있으며, 이 제어 알고리듬을 1자유도계의 시험 구조물에 적용하여 제어 성능을 실험적으로 확인하였다. 본 논문은 이의 연장으로서 제안된 적응형 뱅뱅 제어 알고리듬을 최상층에 유압식 농동질량 감쇠기가 설치된 다자유도계의 시험 구조물에 적용하여 이의 유용성을 확인하였다. 이를 통하여 제안된 적응형 뱅뱅 제어 알고리듬은 제어 및 전체 구조계의 안전성이 보장되는 가운데 과도항 외부의 기진력을 받는 다자유도계의 구조물의 진동을 제어함에 효과적임을 확인할 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.388-391
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• 2010

본 논문에서는 풍하중을 받는 구조물의 응답을 보다 적극적으로 저감시킴으로써 구조물의 안정성과 사용성을 개선하기위한 능동제어 알고리즘을 송도 자유무역 지구에 건설중인 포스코건설 사옥에 수치해석을 통해 적용하여 그 효과를 검증하였다. 수치해석에 의한 시뮬레이션 결과를 보면 최대 제어력이 제한이 된 비선형 제어기가 LQR 제어기와 등등한 제어효과를 가지고 있는 것으로 나타났으며, 제어력의 측면에서 본다면 비선형 제어기법이 더욱 유리한 것을 알 수 있다. 또한, 본 연구에서는 구조물과 질량형 제진장치의 상호작용을 고려하여 통합적으로 제진효과를 해석하고, 이를 바탕으로 제진장치를 설계할 수 있는 소프트웨어를 개발하였다. 구조물의 모드정보에 기초한 축소모델을 구축하고 제진장치의 설계 및 제진성능 평가를 수행하고 사용성을 평가하게 된다. 전체 소프트웨어는 질량형 제진장치의 설계프로그램과 질량형 제진장치의 종류별 대안설계결과를 등가감쇠비로 표현하여 비교평가하는 두 개의 모듈로 이루어져 있으며 전자는 비제어구조물 해석 모듈 및 TMD, TLD, TLCD, AMD를 대상으로 해석 및 설계를 수행하는 총 5개의 하부 모듈로 구성된다. 본 소프트웨어를 현재 TLCD가 설치되어 있는 인천 송도 국제업무지구의 주상복합건물에 적용하여 TMD, TLD, TLCD, AMD의 대안설계를 실시하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.161-169
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• 2004

This paper deals with system identification of a three-story building model with active mass damper (MID) for the controller design. Observer Kalman filter identification (OKID) technique is applied to find the relationship between the experimental results of the input and output. The inputs to the building model with MID are ground accelerations and motor command signal, which are, respectively, simulated earthquake and equivalent control force. The outputs are each floor acceleration and MID acceleration. The MID controller is designed based on the experimentally identified building system. Finally it is shown that experimental results agree accurately with simulated results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.196-201
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• 1999

In active control of structures the stroke of a Hybrid Mass Damper is the one of he main constraints of the system because there is limited installation space available in the structure. To design an optimal controller for a HMD system control objective are defined considering these constraints and effectiveness of H-infinity control method with bilinear transform that satisfies the defined objective is examined for the optimum efficiency. Numerical results show that the proposed H-infinity controller satisfies the constraints and provides optimal performance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.6
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• pp.769-778
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• 2007

In this paper, excitation systems using linear mass shaker (LMS) and active tuned mass damper (ATMD) are presented in order to simulate the wind induced responses of a building structure. The actuator force for the excitation systems is calculated by using the inverse transfer function of a target structural response to the actuator. Filter and envelop function are used such that the error between the wind and actuator induced responses is minimized by preventing the actuator from exciting unexpected modal response and initial transient response. The analyses results from a 76-story benchmark building problem in which wind load obtained by wind tunnel test is given, indicate that the excitation system installed at a specific floor can approximately embody the structural responses induced by the wind load applied to each floor of the structure. The excitation system designed by the proposed method can be effectively used for evaluating the wind response characteristics of a practical building structure and for obtaining an accurate analytical model of the building under wind load.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.57-68
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• 2007

The mega frame system is becoming popular for the design and construction of skyscrapers because this system exhibits structural efficiency by allowing high rigidity of the structure while minimizing the amount of structural materials to be used. Since the mega frame system is usually adopted for super high-rise buildings, the comfort of occupants may be main concerns in the practical application of this system. For the enhancement of the serviceability of mega frame structures, a semi-active tuned mass damper (STMD) is developed in this study. To this end, a Magnetorheological (MR) damper is employed replacing passive damper as a semi-active damper to improve the control effect of a conventional TMD. Since a conventional finite element model of mega frame structures has significant numbers of DOFs, numerical simulation for investigation of control performances of a STMD is impossible by using the full-order model. Therefore, a reduced-order system using minimal DOFs, which can accurately represent the dynamic behavior of a mega frame structure, is proposed in this study through the matrix condensation technique To improve the efficiency of the matrix condensation technique, multi-level matrix condensation technique is proposed using the structural characteristics of mega frame structures. The efficiency and accuracy of the reduced-order control proposed in this study and the control performance of a STMD were verified using example structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.93-102
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• 2006

Control input's saturation of active control devices for large structures under large external disturbances are often occurred. It is more difficult to obtain the exact values of mass and stiffness as structures are higher. The modelling errors between mathematical models and real structures must be also included as parameter uncertainties. Therefore, in active vibration control of civil engineering structures like buildings and bridges, the robust saturation controller design method considering both control input's saturation and parameter uncertainties of system is needed. In this paper, stabilities of linear optimal controller LQR, modified bang-bang controller, saturated sliding mode controller, and robust saturation controller among various controllers which have been studied and applied to active vibration control of buildings are investigated. Especially, unstable phenomena of the LQR, the modified bang-bang controller and the saturated sliding mode controller when the control input is saturated or parameter uncertainties exist are presented to show the necessity of the robust saturation controller. The robust stability of the robust saturation controller are shown through a numerical example of a 2DOF linear vibrating system and an experimental test of the two-story structure with an active mass damper (AMD).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.286-290
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• 2000

Optimal neuro-control algorithm is extended to the control of a multi-degree-of-freedom structure. An active mass driver(AMD) system on the top roof is used as an exciter. The control signals are made by a multi-layer perceptron(MLP) which is trained by minimizing a sub-optimal performance index. The performance index is a function of both the output responses and the control signals. Structure having nonlinear hysteretic behavior is also trained and controlled by using proposed control algorithm. In training neuro-controller, emulator neural network is not used. Instead, sensitivity-test data are used. Therefore, only one neural network is used for the control system. Both the time delay effect and the dynamics of hydraulic actuator are included in the simulation. Example shows that optimal neuro-control algorithm can be applicable to the multi-degree of freedom structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.235-242
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• 2011

The control performance in active structural control system can be drastically deteriorated when the modeling errors and the uncertainties existing in the disturbances are disregarded in the designing stage. It can even throw the control system into an unstable phase, resulting in out of control against the seismic excitations. The purpose of the study is to investigate the control effectiveness of a non-linear control system called sliding mode controller(SMC) in cooperation with a Tuned Mass Damper subjected to the three seismic excitations selected from the FFT analysis. Even though the transient performance such as settling time and overshoot were deteriorated, the robustness against the system stability was appeared from SMC when the structural masses and stiffness perturbed within the range of ${\pm}30%$. SMC is a feasible technique for active structural control in cooperation with TMD against seismic disturbances, exhibiting robustness in perturbation of system stiffness and mass as well as uncertainties of the disturbances.