Experiments on Active Control of Seismic Structures

Chung, Lap-Loi; Reinhorn, A. M.; Soong, T. T.

doi:10.1061/(asce)0733-9399(1988)114:2(241)

Cited by 180 publications

(64 citation statements)

References 2 publications

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“…In the studies mentioned previously, the active control strategies encountered many difficulties including the time delay in the interface of the sensor measurements and the digital controller (Chung et al 1988;Soong and Reinhorn 1993;Quast et al 1995), understanding and modeling of the dynamic behavior of active control devices , feedback control with a robust algorithm and available measurements of structural responses (Spencer et al 1994;Dyke et al 1994a and1994b), control law realization by the digital controller (Dyke et al 1994b;Quast et al 1995). As for the planar motions of isolation bearings attached to the structures, only few experimental studies have considered the multi-directional excitations applying to the base isolated structures (Shook et al 2007); therefore, further studies with consideration of the out-ofplane motions should be investigated.…”

Section: Active Base Isolationmentioning

confidence: 99%

“…In order to represent the structural behavior and the experimental data of these tests accurately, the similitude technique should be applied to this type of problem (Chung et al 1988). Accordingly, since the laboratory instruments might already exist (i.e., the shake table), the structural model should be designed based on the capacity of these instruments.…”

Section: Experimental Researchmentioning

confidence: 99%

“…The active structural systems need to be reliable and workable, and the control algorithms need to include stabilizing characteristics (Fu 1971;Suhardjo et al 1992;Rofooei and Tadjbakhsh 1993;Spencer et al 1994;Kaufman et al 1994;Casciati and Yao 1994;Meirovitch and Stemple 1997;Datta 2003). Numerous experiments have been conducted by researchers (Higashino and Aizawa 1993;Dyke et al 1994a and1994b;Chung et al 1988 and1998) and many real-world implementations have been applied to structures to protect against either wind or earthquakes (Kobori et al 1998 and1991;Soong and Constantinou 1994;Housner et al 1997). Although many successful experiments and implementations prove the active control technology as a practical technique, some potential risks still exist in this real-time implementation; for example, the external energy injection from the active control devices might destabilize the system if the measurements of structural responses have been perturbed, the control laws are developed from a system model that misrepresents the true behavior of systems, the interaction between the structure and the control devices has been exclusively considered in the development of control laws, and so on.…”

Section: Structural Control Technology and Implementationmentioning

confidence: 99%

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Multiaxial active isolation for seismic protection of buildings

Chang

Spencer

Shi

2013

Struct. Control Health Monit.

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Structural control technology has been widely accepted as an effective means for the protection of structures against seismic hazards. Passive base isolation is one of the common structural control techniques used to enhance the performance of structures subjected to severe earthquake excitations. Isolation bearings employed at the base of a structure naturally increase its flexibility, but concurrently result in large base displacements. The combination of base isolation with active control, i.e., active base isolation, creates the possibility of achieving a balanced level of control performance, reducing both floor accelerations as well as base displacements. Many theoretical papers have been written by researchers regarding active base isolation, and a few experiments have been performed to verify these theories; however, challenges in appropriately scaling the structural system and modeling the complex nature of control-structure interaction have limited the applicability of these results. Moreover, most experiments only focus on the implementation of active base isolation under unidirectional excitations. Earthquakes are intrinsically multi-dimensional, resulting in out-of-plane responses, including torsional responses.Therefore, an active isolation system for buildings using multi-axial active control devices against multi-directional excitations must be considered.The focus of this dissertation is the development and experimental verification of active isolation strategies for multi-story buildings subjected to bi-directional earthquake loadings. First, a model building is designed to match the characteristics of a representative full-scale structure.The selected isolation bearings feature low friction and high vertical stiffness, providing stable behavior. In the context of the multi-dimensional response control, three, custom-manufactured actuators are employed to mitigate both in-plane and out-of-plane responses. To obtain a highiii fidelity model of the active isolation systems, a hybrid identification approach is used which combines the advantages of the lumped mass model and nonparametric methods. Controlstructure interaction (CSI) is also included in the identified model to further enhance the control authority. By employing the H 2 /LQG control algorithm, the controllers for the hydraulic actuators promise high performance and good robustness. The active isolation is found to possess the ability to reduce base displacements, as well as producing comparable accelerations over the passive isolation. The proposed active isolation strategies are validated experimentally for a sixstory building tested on the six degree-of-freedom shake table in the Smart Structures Technology Laboratory at the University of Illinois at Urbana-Champaign.iv ACKNOWLEDGMENTS

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Section: Active Base Isolationmentioning

confidence: 99%

Section: Experimental Researchmentioning

confidence: 99%

Section: Structural Control Technology and Implementationmentioning

confidence: 99%

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Multiaxial active isolation for seismic protection of buildings

Chang

Spencer

Shi

2013

Struct. Control Health Monit.

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“…So there have been many studies on control systems with time delay in various research fields such as aeronautical, astronautical, mechanical, chemical and electrical engineering, and many methodologies have been proposed to deal with the control problem of systems with time delay [4][5][6][7]. In vibration control, the technique of time-delay compensation [8][9][10][11] is commonly used to eliminate or reduce the effect of time delay. In the time-delay compensation control method, the controller is first designed by assuming that no time delay exists, and then the feedback gain is modified with time compensation.…”

Section: Introductionmentioning

confidence: 99%

An optimal control method for linear systems with time delay

Cai

Huang

Yang

2003

Computers & Structures

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“…Some of the widely used structural control methods are explained in references [2][3][4]. Among these methods, the classical linear-quadratic-regulator (LQR) optimal control is a simple and effective approach in producing excellent response reduction [5][6][7][8][9]. Moreover, the LQR optimal control method has impressive properties of robustness, including guaranteed classical gain margins of -6dB to +¥dB and phase margins of ±60º in all channels [10].…”

Section: Introductionmentioning

confidence: 99%

Modified LQG/LTR Control Methodology in Active Structural Control

Yan

Wang

Pan

et al. 2003

Journal of Low Frequency Noise, Vibration and Active Control

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This paper presents a new active structural control design methodology comparing the conventional linear-quadratic-Gaussian synthesis with a looptransfer-recovery (LQG/LTR) control approach for structures subjected to ground excitations. It results in an open-loop stable controller. Also the closedloop stability can be guaranteed. More importantly, the value of the controller's gain required for a given degree of LTR is orders of magnitude less than what is required in the conventional LQG/LTR approach. Additionally, for the same value of gain, the proposed controller achieves a much better degree of recovery than the LQG/LTR-based controller. Once this controller is obtained, the problems of control force saturation are either eliminated or at least dampened, and the controller band-width is reduced and consequently the control signal to noise ratio at the input point of the dynamic system is increased. Finally, numerical examples illustrate the above advantages.

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Experiments on Active Control of Seismic Structures

Cited by 180 publications

References 2 publications

Multiaxial active isolation for seismic protection of buildings

Multiaxial active isolation for seismic protection of buildings

An optimal control method for linear systems with time delay

Modified LQG/LTR Control Methodology in Active Structural Control

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