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Hojjat Adeli - One of the best experts on this subject based on the ideXlab platform.

  • neuro genetic algorithm for non linear active Control of Structures
    International Journal for Numerical Methods in Engineering, 2008
    Co-Authors: Xiaomo Jiang, Hojjat Adeli
    Abstract:

    In a companion paper, a new non-linear Control model was presented for active Control of three-dimensional (3D) building Structures including geometrical and material non-linearities, coupling action between lateral and torsional motions, and actuator dynamics (Int. J. Numer. Meth. Engng; DOI: 10.1002/nme.2195). A dynamic fuzzy wavelet neuroemulator was presented for predicting the structural response in future time steps. In this paper, a new neuro-genetic algorithm or Controller is presented for finding the optimal Control forces. The Control algorithm does not need the pre-training required in a neural network-based Controller, which improves the efficiency of the general Control methodology significantly. Two 3D steel building Structures, a 12-story structure with vertical setbacks and an 8-story structure with plan irregularity, are used to validate the neuro-genetic Control algorithm under three different seismic excitations. Numerical validations demonstrate that the new Control methodology significantly reduces the displacements of buildings subjected to various seismic excitations including Structures with plan and elevation irregularities.

  • dynamic fuzzy wavelet neuroemulator for non linear Control of irregular building Structures
    International Journal for Numerical Methods in Engineering, 2008
    Co-Authors: Xiaomo Jiang, Hojjat Adeli
    Abstract:

    A new non-linear Control model is presented for active Control of three-dimensional (3D) building Structures. Both geometrical and material non-linearities are included in the structural Control formulation. A dynamic fuzzy wavelet neuroemulator is presented for predicting the structural response in future time steps. Two dynamic coupling actions are taken into account simultaneously in the Control model: (a) coupling between lateral and torsional motions of the structure and (b) coupling between the actuator and the structure. The new neuroemulator is validated using two irregular 3D steel building Structures, a 12-story structure with vertical setbacks and an 8-story structure with plan irregularity. Numerical validations in both time and frequency domains demonstrate that the new neuroemulator provides accurate prediction of structural displacement responses, which is required in neural network models for active Control of Structures. In the companion paper, a floating-point genetic algorithm is presented for finding the optimal Control forces needed for active non-linear Control of building Structures using the dynamic fuzzy wavelet neuroemulator presented in this paper. Copyright © 2007 John Wiley & Sons, Ltd.

  • wind induced motion Control of 76 story benchmark building using the hybrid damper tlcd system
    Journal of Structural Engineering-asce, 2005
    Co-Authors: Hojjat Adeli
    Abstract:

    The tuned liquid column damper (TLCD) has recently been advanced for vibration Control of Structures subjected to wind loading. The effectiveness of the semiactive TLCD system and the hybrid viscous fluid damper-TLCD Control system recently proposed by the writers is investigated for Control of wind-induced motion of high-rise buildings. Simulations are performed on a 76-story building benchmark Control problem subjected to wind tunnel test data and stochastic wind loads. It is shown that the semiactive TLCD Control system performs comparably to a sample active tuned mass damper (ATMD) system and thus is an attractive alternative to the ATMD system. More significantly, it is shown that the hybrid viscous fluid damper-TLCD system reduces the response of the building substantially more than the semiactive TLCD system at every natural frequency of the building. Furthermore, the hybrid damper-TLCD system is robust in terms of the stiffness modeling error for Control of both displacement and acceleration responses. The simulation results show that the proposed hybrid viscous fluid damper-TLCD system can perform effectively under various wind loading conditions.

  • wavelet hybrid feedback least mean square algorithm for robust Control of Structures
    Journal of Structural Engineering-asce, 2004
    Co-Authors: Hojjat Adeli, Hongjin Kim
    Abstract:

    In a companion article, the writers presented a hybrid feedback-least mean square (LMS) algorithm for Control of Structures through integration of a feedback Control algorithm such as the linear quadratic regulator and linear quadratic Gaussian algorithms and the filtered-x LMS algorithm. Low-pass filtering of dynamic environmental disturbance signals due to winds and earthquakes is required when the hybrid feedback-LMS algorithm is used for Control of civil Structures, because the frequency bandwidths of such environmental signals are much wider than those of common structural systems. In this paper, it is shown that the wavelet transform can be used as an effective filtering scheme for Control problems. A wavelet-hybrid feedback-LMS algorithm is presented for robust Control of civil Structures. The effectiveness of the proposed Control model is demonstrated by application to an active tuned mass damper system and an active mass driver benchmark problem. Simulation results demonstrate that the proposed model is effective for Control of both steady and transient vibrations without any significant additional computational burden, and can be used readily to enhance the performance of existing feedback Control algorithms.

  • hybrid feedback least mean square algorithm for structural Control
    Journal of Structural Engineering-asce, 2004
    Co-Authors: Hongjin Kim, Hojjat Adeli
    Abstract:

    Classical Control algorithms such as the linear quadratic regulator ~LQR! and linear quadratic Gaussian ~LQG! algorithms have been used for structural Control problems over the past three decades. These algorithms suffer from a number of fundamental shortcomings. They are susceptible to parameter uncertainty and modeling error. They present optimum solutions in a narrow sense only because the external excitation term is ignored in their formulation and solution. These algorithms achieve a significant level of attenu- ation in the vicinity of the natural frequencies of the structure. But, they fail to suppress the vibrations when frequency of the external disturbance differs even slightly from the natural frequencies of the structure. In this paper, a hybrid feedback-least mean square ~LMS! algorithm is presented for Control of Structures through integration of a feedback Control algorithm such as the LQR or LQG algorithm and the filtered-x LMS algorithm. The algorithm is applied to the active tuned mass damper system. It is shown that the hybrid feedback-LMS algorithm minimizes vibrations over the entire frequency range and thus is less susceptible to modeling error and inherently more stable.

Sameer Vittal - One of the best experts on this subject based on the ideXlab platform.

  • active vibration Control of cantilever beam by using pid based output feedback Controller
    Journal of Vibration and Control, 2012
    Co-Authors: S. M. Khot, Nitesh P Yelve, Rajat Tomar, Sameer Desai, Sameer Vittal
    Abstract:

    Undesired noise and vibrations have a detrimental effect in many areas. Hence the Control of vibrations has become a relevant technological challenge. Active vibration Control of Structures using smart materials is especially in vogue. This involves sensing the motion of the structure using sensors, generating a Control signal using a Controller and applying a Control force on the structure using actuators. To design the Control system of any vibrating structure, the mathematical model of the system is required. However, it is difficult to theoretically construct a model of complex Structures. On the other hand, it is relatively simpler to model such systems in a Finite Element (FE) environment like ANSYS©. This paper deals with the extraction of the full and reduced mathematical models of a cantilever beam into MATLAB© from its FE model. The full model of the beam is reduced by discarding those modes which do not contribute to the overall response. It is found that the frequency and transient responses o...

  • active vibration Control of cantilever beam by using pid based output feedback Controller
    Journal of Vibration and Control, 2012
    Co-Authors: S. M. Khot, Nitesh P Yelve, Rajat Tomar, Sameer Desai, Sameer Vittal
    Abstract:

    Undesired noise and vibrations have a detrimental effect in many areas. Hence the Control of vibrations has become a relevant technological challenge. Active vibration Control of Structures using s...

Hongjin Kim - One of the best experts on this subject based on the ideXlab platform.

  • wavelet hybrid feedback least mean square algorithm for robust Control of Structures
    Journal of Structural Engineering-asce, 2004
    Co-Authors: Hojjat Adeli, Hongjin Kim
    Abstract:

    In a companion article, the writers presented a hybrid feedback-least mean square (LMS) algorithm for Control of Structures through integration of a feedback Control algorithm such as the linear quadratic regulator and linear quadratic Gaussian algorithms and the filtered-x LMS algorithm. Low-pass filtering of dynamic environmental disturbance signals due to winds and earthquakes is required when the hybrid feedback-LMS algorithm is used for Control of civil Structures, because the frequency bandwidths of such environmental signals are much wider than those of common structural systems. In this paper, it is shown that the wavelet transform can be used as an effective filtering scheme for Control problems. A wavelet-hybrid feedback-LMS algorithm is presented for robust Control of civil Structures. The effectiveness of the proposed Control model is demonstrated by application to an active tuned mass damper system and an active mass driver benchmark problem. Simulation results demonstrate that the proposed model is effective for Control of both steady and transient vibrations without any significant additional computational burden, and can be used readily to enhance the performance of existing feedback Control algorithms.

  • hybrid feedback least mean square algorithm for structural Control
    Journal of Structural Engineering-asce, 2004
    Co-Authors: Hongjin Kim, Hojjat Adeli
    Abstract:

    Classical Control algorithms such as the linear quadratic regulator ~LQR! and linear quadratic Gaussian ~LQG! algorithms have been used for structural Control problems over the past three decades. These algorithms suffer from a number of fundamental shortcomings. They are susceptible to parameter uncertainty and modeling error. They present optimum solutions in a narrow sense only because the external excitation term is ignored in their formulation and solution. These algorithms achieve a significant level of attenu- ation in the vicinity of the natural frequencies of the structure. But, they fail to suppress the vibrations when frequency of the external disturbance differs even slightly from the natural frequencies of the structure. In this paper, a hybrid feedback-least mean square ~LMS! algorithm is presented for Control of Structures through integration of a feedback Control algorithm such as the LQR or LQG algorithm and the filtered-x LMS algorithm. The algorithm is applied to the active tuned mass damper system. It is shown that the hybrid feedback-LMS algorithm minimizes vibrations over the entire frequency range and thus is less susceptible to modeling error and inherently more stable.

S. M. Khot - One of the best experts on this subject based on the ideXlab platform.

  • active vibration Control of cantilever beam by using pid based output feedback Controller
    Journal of Vibration and Control, 2012
    Co-Authors: S. M. Khot, Nitesh P Yelve, Rajat Tomar, Sameer Desai, Sameer Vittal
    Abstract:

    Undesired noise and vibrations have a detrimental effect in many areas. Hence the Control of vibrations has become a relevant technological challenge. Active vibration Control of Structures using smart materials is especially in vogue. This involves sensing the motion of the structure using sensors, generating a Control signal using a Controller and applying a Control force on the structure using actuators. To design the Control system of any vibrating structure, the mathematical model of the system is required. However, it is difficult to theoretically construct a model of complex Structures. On the other hand, it is relatively simpler to model such systems in a Finite Element (FE) environment like ANSYS©. This paper deals with the extraction of the full and reduced mathematical models of a cantilever beam into MATLAB© from its FE model. The full model of the beam is reduced by discarding those modes which do not contribute to the overall response. It is found that the frequency and transient responses o...

  • active vibration Control of cantilever beam by using pid based output feedback Controller
    Journal of Vibration and Control, 2012
    Co-Authors: S. M. Khot, Nitesh P Yelve, Rajat Tomar, Sameer Desai, Sameer Vittal
    Abstract:

    Undesired noise and vibrations have a detrimental effect in many areas. Hence the Control of vibrations has become a relevant technological challenge. Active vibration Control of Structures using s...

Subrata Chakraborty - One of the best experts on this subject based on the ideXlab platform.

  • robust optimum design of base isolation system in seismic vibration Control of Structures under random system parameters
    Structural Safety, 2015
    Co-Authors: Subrata Chakraborty
    Abstract:

    Abstract The optimum design of base isolation system to Control seismic vibration considering uncertain system parameters are usually performed by minimizing the unconditional expected value of mean square response of a structure without any consideration to the variance of such responses due to system parameter uncertainty. However, the unconditional mean square response based designed may have larger variance of responses due to uncertainty in system parameters and the overall system performance may be sensitive. But, it is desirable that the optimum design should reduce both the mean and variance of dynamic performance measure under system parameter uncertainty. The present study deals with robust design optimization (RDO) of base isolation system considering random system parameters characterizing the structure, isolator and ground motion model. The RDO is performed by minimizing the weighted sum of the expected value of the maximum root mean square acceleration of the structure as well its standard deviation. A numerical study elucidates the importance of the RDO procedure for design of base isolation system by comparing the proposed RDO results with the results obtained by the conventional stochastic structural optimization procedure and the unconditional response based optimization.

  • reliability based optimum design of tuned mass damper in seismic vibration Control of Structures with bounded uncertain parameters
    Probabilistic Engineering Mechanics, 2011
    Co-Authors: Subrata Chakraborty
    Abstract:

    Abstract A reliability based optimization of Tuned Mass Damper (TMD) parameters in seismic vibration Control under bounded uncertain system parameters is presented. The study on TMD with random parameters in a probabilistic framework is noteworthy. But, it cannot be applied when the necessary information about parameters uncertainties is limited. In such cases, the interval method is a viable alternative. Applying matrix perturbation theory through a first order Taylor series expansion about the mean values of the uncertain parameters’ conservative dynamic response bounds are obtained assuming a small degree of parameter uncertainty. The first-passage probability of failure of the system is taken as the performance objective. Using the interval extension of the performance objective, the vibration Control problem under bounded uncertainties is transformed to the appropriate deterministic optimization problems yielding the lower and upper bound solutions. A numerical study is performed to elucidate the effect of parameters’ uncertainties on the TMD parameters’ optimization and the safety of the structure.