A method for fast simulation of seismically excited active controlled MDOF structures

Agranovich, G.; Ribakov, Yuri; Blostotsky, B.

doi:10.1002/stc.52

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…The control system should be realized in a digital form, hence the differential equations (1) are transformed to an equivalent system of finite-differences equations, based on an equivalent transformation technique [14,20,21]:…”

Section: Calibration Of Active Controlled Systemmentioning

confidence: 99%

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A method for efficient placement of active dampers in seismically excited structures

Agranovich

Ribakov

2009

Struct. Control Health Monit.

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Using supplemental active and semi-active dampers is known as an efficient way for improving structural response to earthquakes. An actual problem that should be solved by the engineer is how many dampers should be used and what is their optimal location yielding the desired structural response by minimum cost. The last one usually depends on the price of a damping unit and its connection to the frame, number of damping units and energy required for activation of the control system in order to realize the optimal control algorithm. In this paper, the following heuristic solution of this problem is proposed. This solution is based on the well-known LQG design of active dampers. It is first assumed that the LQG controlled dampers are located at each floor. Energy, dissipated in the dampers at each floor, is obtained and most effective dampers' locations are selected according to maximum contribution to the total energy dissipation. A procedure for realization of this idea is proposed. Effectiveness of the proposed method is demonstrated in a numerical example. It shows a promising way for effective improvement of structural seismic response by a limited set of damping units. researchers have studied the influence of placement of passive dampers on seismic behavior of structures [5,6]. Hahn and Sathiavageeswarm [7] showed that in buildings with uniform storey stiffness distribution dampers should be placed in the lower floors. Gluck et al. [8] have proposed a strategy for optimal selection of viscous dampers' properties based on system response and control gain matrix. A wide literature review in this field is given by Liu [1].A systematic procedure for finding the optimal damper positioning, aimed at minimizing the dynamic compliance of a planar building frame, was proposed by Takewaki [9]. The dynamic compliance was expressed in terms of the transfer function from earthquake acceleration excitation to inter-storey drifts amplitudes, evaluated at the undamped fundamental natural frequency. The dynamic compliance was minimized subject to a constraint on the sum of the damping coefficients of added viscous dampers. Optimality criteria were derived and the optimal damper positioning was determined based on steepest direction search algorithm, allowing finding an optimal damper positioning sequentially for gradually increasing total damper capacity levels.A method for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant structures was developed by Cheng et al. [10]. It includes a statistical criterion, formulation of an optimization problem and establishment of a solution procedure. The method is simple and general, and the optimally applied dampers and actuators are very efficient for seismic response reduction.Another approach is to use genetic algorithm. This approach was used by Singh and Moreschi [5] for investigating placement of passive energy dissipation devices in a multistorey building for seismic protection. Wongprasert and Symans [11] have used this approa...

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Section: Calibration Of Active Controlled Systemmentioning

confidence: 99%

“…The results of such calculation are presented in Tables II, IV and V for uncontrolled and controlled structure. Optimal choice of diagonal elements of matrix Q was performed using a method, proposed by Agranovich et al [20,21]. The global performance index W 1 (Q) is assigned as…”

Section: Calibration Of Active Controlled Systemmentioning

confidence: 99%

A method for efficient placement of active dampers in seismically excited structures

Agranovich

Ribakov

2009

Struct. Control Health Monit.

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“…Generally, the performance of a digital controller improves with increasing sampling rate, but costs may also increase with faster sampling; conversely, a slower sampling entails more time for control calculations and so slower computers with smaller word sizes and cheap A/D converters can be used. Thus generally, the slowest sample rate that meets all performance specifications is sought.Though numerous studies have dealt with the stability and robustness properties of adaptive controllers [17,18], there is still a paucity of publications devoted to the clarification of specific computational issues, such as accuracy, stability, frequency behaviour, optimal choice of the sampling period and computational efficiency [19,20]. In detail, none of these aspects was considered yet for the MCS algorithm.…”

mentioning

confidence: 99%

“…Though numerous studies have dealt with the stability and robustness properties of adaptive controllers [17,18], there is still a paucity of publications devoted to the clarification of specific computational issues, such as accuracy, stability, frequency behaviour, optimal choice of the sampling period and computational efficiency [19,20]. In detail, none of these aspects was considered yet for the MCS algorithm.…”

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confidence: 99%

Convergence and frequency-domain analysis of a discrete first-order model reference adaptive controller

Bursi

Stoten

Vulcan

2007

Struct. Control Health Monit.

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We study the convergence properties of a direct model reference adaptive control system by applying techniques from numerical analysis. In particular, a first-order discrete system coupled to a minimal control synthesis algorithm discretized by the one-step one-stage zero-order-hold sampling is studied. This results in a strongly non-linear dynamic system owing to the adaptive mechanism where stability at steady state, i.e. at the operating point, equates to successful control. This paper focuses on the convergence analysis of the overall dynamical system for understanding accuracy, stability and performance at steadystate. The local stability of the steady state solution is considered by linearizing the system in the neighbourhood of an operating point when the input is a step function. This analysis allows us to specify two gain space domains which define the region of local stability. Moreover, both the accuracy and the frequency-domain analyses give insight into the range of adaptive control weightings that results in optimal performance of the minimal control synthesis algorithm and also highlights a possible approach to a priori selection of the time step and adaptive weighting values.The effectiveness of the proposed analysis is further demonstrated by simulations and experiments on a first-order plant.Adaptive control methods are generally divided into (i) direct and (ii) indirect methods. In the first case the adjustment rules provide directly how to update the controller parameters; in the indirect methods, the parameters of the unknown plant are estimated on-line, and the controller parameters are calculated on the base of these estimates. In the context of control theory some recent books and papers relevant to direct methods can be found [2,3]. In the context of structural control several applications have been made by several researches as well [4][5][6].When a direct reference model controller is used, it can be also applied to systems where the details of the plant cannot be fully known a priori or are varying with time. Using this type of algorithms without the knowledge of plant parameters, such that we assume zero initial conditions for the controller gains, has become known as the minimal control synthesis (MCS) approach [7]. Basing adaptive control schemes on a reference model enables the system to be controlled to behave like the model itself. This type of approach [8,9] has been applied to a wide range of systems including non-linear and chaotic systems [3,10]. As the approach is based primarily on linear control theory being the reference model usually a linear one, the effect of non-linearities and/or disturbances in non-linear systems is compensated for by the adaptive nature of the controller. Very recently in the field of dynamic and seismic testing [11], the MCS method was used in real-time substructuring, in order to minimize the error between displacements imposed by the actuators on the substructure and displacements at the interfaces of the numerical model [12,13]; and it was adop...

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Using viscous and variable friction dampers for improving structural seismic response

Ribakov

2010

Structural Design Tall Build

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Using supplemental dampers is known as an efficient way for improving structural seismic response. Viscous, friction, yielding steel and other types of dampers were developed in the last few decades for this reason and are produced by the industry and used in modern structures and in retrofitted buildings all over the world. This paper is focused on investigating a damping system including viscous and variable friction dampers. Numerical analysis of a multi‐storey structure was carried out. At the first stage, the structure was provided by optimal viscous dampers and its response to a white noise was obtained. According to this response, appropriate parameters of variable friction dampers were obtained using an equivalent energy dissipation hypothesis. At the second stage, dynamic response of the structure under real seismic motions was studied. It was shown that using a hybrid damping system including viscous and variable friction dampers yields essential improvement in structural response and looks attractive for practical implementations. Copyright © 2010 John Wiley & Sons, Ltd.

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A method for fast simulation of seismically excited active controlled MDOF structures

Cited by 3 publications

References 6 publications

A method for efficient placement of active dampers in seismically excited structures

A method for efficient placement of active dampers in seismically excited structures

Convergence and frequency-domain analysis of a discrete first-order model reference adaptive controller

Using viscous and variable friction dampers for improving structural seismic response

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