Active Structural Control Based on the Prediction and Degree of Stability

Aldemir, Ünal; Bakioglu, M.

doi:10.1006/jsvi.2001.3689

Cited by 32 publications

(17 citation statements)

References 9 publications

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“…() developed an approximately optimal closed‐open‐loop control based on the prediction of near‐future excitations provided that a given norm criteria is satisfied. Aldemir and Bakioglu () analytically solved the modified linear quadratic regulator (MLQR) problem including a parameter representing system stability order in the presence of unknown seismic excitations. Mei et al.…”

Section: Introductionmentioning

confidence: 99%

Active Tendon Control of Torsionally Irregular Structures under Near‐Fault Ground Motion Excitation

Niğdeli

Boduroğlu

2013

Computer aided Civil Eng

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Section: Introductionmentioning

confidence: 99%

Active Tendon Control of Torsionally Irregular Structures under Near‐Fault Ground Motion Excitation

Niğdeli

Boduroğlu

2013

Computer aided Civil Eng

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“…Owing to recent developments of digital control and measurement techniques, semiactive and active control techniques in the structural technology have received much attention (Bakioglu and Aldemir, 2001; Aldemir and Bakioglu, 2001; Aldemir, 2003, 2009; Saleh and Adeli, 1998b; Adeli and Saleh, 1998; Aldemir and Gavin, 2006; Alhan et al, 2006; Gavin and Aldemir, 2005). Active control methods are effective for a wide frequency range as well as for transient vibrations.…”

Section: Introductionmentioning

confidence: 99%

A Simple Active Control Algorithm for Earthquake Excited Structures

Aldemir

2010

Computer aided Civil Eng

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A simple integral type quadratic functional is proposed as the performance index so that the optimal control policy is derived based on the minimization of the proposed performance index between the successive control instants by using the method of calculus of variations. The resulting optimal control law is applied to seismically excited linear buildings modeled as lumped mass shear frame structures. Active tendon actuators are considered as control devices. The performance of the proposed control (PC) is investigated when the example structure is subjected to three different seismic inputs and compared to the uncontrolled case and the classical linear optimal control (CLOC), which requires the solution of nonlinear matrix Riccati equation. It is shown by numerical simulation results that the PC is capable of suppressing the uncontrolled seismic vibrations of the linear structures and performs better than the CLOC.

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“…Because of the Heaviside step function in (2), analytical expressions for the frequency response function cannot be obtained. Frequency response functions for semiactively controlled structures can however be constructed by numerically integrating the system equations until a harmonic steady state is reached, and plotting the ratio of the response amplitude to the excitation amplitude as a function of the frequency ratio.…”

mentioning

confidence: 98%

“…The graphical representation of the continuous pseudo-skyhook control force (2) is also given in Fig. 1.…”

mentioning

confidence: 99%

“…Civil engineering structures incorporating semiactive devices exhibit nonlinear behavior and this motivates the development of nonlinear control strategies that can be practically implemented, which is a challenging task. As is well known, optimal control problem of a linear system with respect to a quadratic performance index has a flexible solution, which leads to the construction of a linear state regulator when there are no constraints on admissible controls [1][2][3]. It is known to the control community that except for relatively few special cases, the mathematical theory of nonlinear oscillations provides little help for practical nonlinear vibration control problems [6].…”

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Optimal semiactive control of structures with isolated base

Aldemir

Gavin

2006

Int Appl Mech

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The paper investigates the benefits of implementing the semiactive control systems in relation to passive viscous damping in the context of seismically isolated structures. Frequency response functions are compiled from the computed time history response to pulse-like seismic excitation. A simple semiactive control policy is evaluated in regard to passive linear viscous damping and an optimal non-causal semiactive control strategy. The optimal control strategy minimizes the integral of the squared absolute accelerations subject to the constraint that the nonlinear equations of motion are satisfied. The optimization procedure involves a numerical solution to the Euler-Lagrange equations Keywords: optimal control, Euler-Lagrange equations, nonlinear systems Introduction. Passive and active control techniques have been studied in various engineering fields [4, 5, 8, 9, 11-13, 15, 17]. Application of various techniques to civil engineering has been the subject of considerable research since the pioneer work of Yao [16]. Now, the trend in practice for passive isolation systems is toward very large isolators incorporating large viscous dampers. Recent studies show that the use of supplemental dampers in seismic isolation to increase the isolation damping reduce displacements, but at the expense of increases in interstory displacements and accelerations at high frequencies in the superstructure [7]. An increase in the interstory drifts and superstructure accelerations is counter to the primary goal of isolation systems: to protect the sensitive internal equipment and non-structural elements.Semiactive control systems, on the other hand, are a class of control systems in which the control actions are applied by changing the mechanical properties (i.e., stiffness and damping) of the control device [10]. Civil engineering structures incorporating semiactive devices exhibit nonlinear behavior and this motivates the development of nonlinear control strategies that can be practically implemented, which is a challenging task. As is well known, optimal control problem of a linear system with respect to a quadratic performance index has a flexible solution, which leads to the construction of a linear state regulator when there are no constraints on admissible controls [1][2][3]. It is known to the control community that except for relatively few special cases, the mathematical theory of nonlinear oscillations provides little help for practical nonlinear vibration control problems [6]. Therefore, the difficulties in synthesizing optimal feedback controls for nonlinear non-autonomous dynamical systems have motivated many researchers to use the formalism of optimal control theory to derive sub-optimal feedback controllers by obtaining approximate solutions to either the two-point boundary-value problem or to the Hamilton-JacobiBellman equations. Numerical solution to the two-point boundary-value problem for nonlinear non-autonomous dynamical systems can also be found using numerical optimization techniques. The resulting optimal c...

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Active Structural Control Based on the Prediction and Degree of Stability

Cited by 32 publications

References 9 publications

Active Tendon Control of Torsionally Irregular Structures under Near‐Fault Ground Motion Excitation

Active Tendon Control of Torsionally Irregular Structures under Near‐Fault Ground Motion Excitation

A Simple Active Control Algorithm for Earthquake Excited Structures

Optimal semiactive control of structures with isolated base

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