Application of semi-active control strategies for seismic protection of buildings with MR dampers

Smart structural control is now emerging as an alternative to conventional earthquake resistant design and traditional structural control techniques. Fuzzy logic based control is one of the promising smart control strategies that could be used for this function. Magneto Rheological (MR) dampers are considered one of the promising semi-active control devices that can be used to control the structural response of buildings under earthquake excitation. The properties of MR dampers can be controlled using several smart techniques such as Fuzzy Logic. In this paper, a comparative analysis is conducted to investigate the most optimum location for placing MR dampers, which are controlled by Fuzzy Logic, in a three-degree-of-freedom benchmark problem. The study explores three potential schemes for allocating and operating MR dampers within the system under consideration. Two main structural response parameters are considered in this study, maximum displacement and maximum acceleration. In addition, the study investigates the lowest number of fuzzy-controlled MR dampers that are required in order to produce the required structural behaviour. This is an initial step towards the development of a generic allocation algorithm that is capable of identifying the required number of MR dampers, and their location, for controlling any multi-degree-of-freedom system.

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CONTROL OF WIND-INDUCED RESPONSE OF TRANSMISSION TOWER-LINE SYSTEM BY USING MAGNETORHEOLOGICAL DAMPERS

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455409003235 ◽

2009 ◽

Vol 09 (04) ◽

pp. 661-685 ◽

Cited By ~ 39

Author(s):

BO CHEN ◽

JIN ZHENG ◽

WEILIAN QU

Keyword(s):

Active Control ◽

Passive Control ◽

Control Strategies ◽

Wind Loading ◽

Induced Response ◽

Strong Wind ◽

Transmission Tower ◽

Line System ◽

Control Approach ◽

Mr Dampers

Transmission tower-line system is a high-rise structure with low damping and it is therefore prone to strong wind excitation. In this paper, the control of wind-induced response of transmission tower-line system is carried out by using magnetorheological (MR) dampers. The effects of brace stiffness of damper are introduced and a multi-degree-of-freedom (MDOF) model is developed for both in-plane/out-of-plane vibration of transmission tower-line system. Two semi-active control strategies are proposed for the vibration mitigation of tower-line system. The first one is based on fixed increment of controllable damper force whereas the second one is a clipped-optimal strategy based on fuzzy control principle. The optimal parameters of the MDOF model of transmission line are investigated. A real transmission tower-line system constructed in China is taken as an example to examine the feasibility and reliability of the proposed approach. A parametric study is conducted for the effects of brace stiffness of MR damper, wind loading intensity, and parameters of MR fluids on the control performance. The results demonstrate that the incorporation of MR dampers into the transmission tower-line system can substantially suppress the wind-induced responses of transmission tower if the damper parameters are optimally determined. The performance of the two kinds of semi-active control approaches is better than that of a passive control approach.

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Application of Support Vector Machine-Based Semiactive Control for Seismic Protection of Structures with Magnetorheological Dampers

Mathematical Problems in Engineering ◽

10.1155/2012/268938 ◽

2012 ◽

Vol 2012 ◽

pp. 1-18

Author(s):

Chunxiang Li ◽

Qing Liu ◽

Shengning Lan

Keyword(s):

Support Vector Machine ◽

Control Strategy ◽

Control Strategies ◽

Seismic Protection ◽

Support Vector ◽

Semiactive Control ◽

Mr Dampers ◽

Acceleration Amplification ◽

Switch Control ◽

Lqr Controller

Based on recent research by Li and Liu in 2011, this paper proposes the application of support vector machine- (SVM-) based semiactive control methodology for seismic protection of structures with magnetorheological (MR) dampers. An important and challenging task of designing the MR dampers is to develop an effective semiactive control strategy that can fully exploit the capabilities of MR dampers. However, amplification of the local acceleration response of structures exists in the widely used semiactive control strategies, namely “Switch” control strategies. Then the SVM-based semiactive control strategy has been employed to design MR dampers. Firstly, the LQR controller for the numerical model of a multistory structure formulated using the dynamic dense method is constructed by using the classic LQR control theory. Secondly, an SVM model which comprises the observers and controllers in the control system is designed and trained to emulate the performance of the LQR controller. Finally, an online autofeedback semiactive control strategy is developed by resorting to SVM and then used for designing MR dampers. Simulation results show that the MR dampers utilizing the SVM-based semiactive control algorithm, which eliminates the local acceleration amplification phenomenon, can remarkably reduce the displacement, velocity, and acceleration responses of the structure.

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Active Control of Greenhouse Climate Enhances Papaya Growth and Yield at an Affordable Cost

Agronomy ◽

10.3390/agronomy11020378 ◽

2021 ◽

Vol 11 (2) ◽

pp. 378

Author(s):

Irene Salinas ◽

Juan José Hueso ◽

Julián Cuevas

Keyword(s):

Active Control ◽

Skin Color ◽

Natural Ventilation ◽

Control Strategies ◽

Soluble Solids ◽

Growth And Yield ◽

Climate Control ◽

Tropical Fruit ◽

Greenhouse Climate ◽

Solids Content

Papaya is a tropical fruit crop that in subtropical regions depends on protected cultivation to fulfill its climate requirements and remain productive. The aim of this work was to compare the profitability of different climate control strategies in greenhouses located in subtropical areas of southeast Spain. To do so, we compared papayas growing in a greenhouse equipped with active climate control (ACC), achieved by cooling and heating systems, versus plants growing in another greenhouse equipped with passive climate control (PCC), consisting of only natural ventilation through zenithal and lateral windows. The results showed that ACC favored papaya plant growth; flowering; fruit set; and, consequently, yields, producing more and heavier fruits at an affordable cost. Climate control strategies did not significantly improve fruit quality, specifically fruit skin color, acidity, and total soluble solids content. In conclusion, in the current context of prices, an active control of temperature and humidity inside the greenhouse could be a more profitable strategy in subtropical regions where open-air cultivation is not feasible.

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The Use of Damping Based Semi-Active Control Algorithms in the Mechanical Smart-Spring System

Journal of Vibration and Acoustics ◽

10.1115/1.4038034 ◽

2017 ◽

Vol 140 (2) ◽

Cited By ~ 1

Author(s):

Wander Gustavo Rocha Vieira ◽

Fred Nitzsche ◽

Carlos De Marqui

Keyword(s):

Active Control ◽

Control Algorithm ◽

Control Strategies ◽

Vibration Reduction ◽

Flow Analysis ◽

Coupled Systems ◽

Control Technique ◽

Control Algorithms ◽

Control Techniques ◽

Spring Mechanism

In recent decades, semi-active control strategies have been investigated for vibration reduction. In general, these techniques provide enhanced control performance when compared to traditional passive techniques and lower energy consumption if compared to active control techniques. In semi-active concepts, vibration attenuation is achieved by modulating inertial, stiffness, or damping properties of a dynamic system. The smart spring is a mechanical device originally employed for the effective modulation of its stiffness through the use of semi-active control strategies. This device has been successfully tested to damp aeroelastic oscillations of fixed and rotary wings. In this paper, the modeling of the smart spring mechanism is presented and two semi-active control algorithms are employed to promote vibration reduction through enhanced damping effects. The first control technique is the smart-spring resetting (SSR), which resembles resetting control techniques developed for vibration reduction of civil structures as well as the piezoelectric synchronized switch damping on short (SSDS) technique. The second control algorithm is referred to as the smart-spring inversion (SSI), which presents some similarities with the synchronized switch damping (SSD) on inductor technique previously presented in the literature of electromechanically coupled systems. The effects of the SSR and SSI control algorithms on the free and forced responses of the smart-spring are investigated in time and frequency domains. An energy flow analysis is also presented in order to explain the enhanced damping behavior when the SSI control algorithm is employed.

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A comparison of semi-active control strategies for the MR damper

Proceedings Intelligent Information Systems. IIS'97 ◽

10.1109/iis.1997.645424 ◽

2002 ◽

Cited By ~ 38

Author(s):

S.J. Dyke ◽

B.F. Spencer

Keyword(s):

Active Control ◽

Control Strategies ◽

Mr Damper

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On the Efficacy of Magnetorheological Dampers for Seismic Response Reduction

Volume 1B: 16th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc97/vib-3828 ◽

1997 ◽

Author(s):

S. J. Dyke ◽

B. F. Spencer ◽

M. K. Sain ◽

J. D. Carlson

Keyword(s):

Control Systems ◽

Structural Response ◽

Mr Damper ◽

Seismic Protection ◽

Seismic Excitations ◽

One Dimensional ◽

Mr Dampers ◽

Earthquake Motion ◽

Intrinsic Nonlinearity ◽

Series Of Experiments

Abstract In this paper, the efficacy of magnetorheological (MR) dampers for seismic protection of structures is investigated through a series of experiments in which an MR damper is used to control a three story test structure subjected to a one-dimensional earthquake motion. Because of the intrinsic nonlinearity of the MR damper, several earthquake amplitudes are considered to investigate the performance, in terms of both peak and rms responses, of this control systems over a range of loading conditions. The results indicate that the MR damper is quite effective for structural response reduction over a wide class of seismic excitations.

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A shuffled frog-leaping algorithm based mixed-sensitivity H∞ control of a seismically excited structural building using MR dampers

Journal of Vibration and Control ◽

10.1177/1077546317695462 ◽

2017 ◽

Vol 24 (13) ◽

pp. 2832-2852 ◽

Cited By ~ 4

Author(s):

Xiufang Lin ◽

Shumei Chen ◽

Guorong Huang

Keyword(s):

Active Control ◽

Passive Control ◽

Structural Parameters ◽

Mr Damper ◽

Inverse Model ◽

Shuffled Frog Leaping Algorithm ◽

Weighting Functions ◽

Inference System ◽

Mr Dampers ◽

Shuffled Frog Leaping

An intelligent robust controller, which combines a shuffled frog-leaping algorithm (SFLA) and an H∞ control strategy, is designed for a semi-active control system with magnetorheological (MR) dampers to reduce seismic responses of structures. Generally, the performance of mixed-sensitivity H∞ (MSH) control highly depends on expert experience in selecting the parameters of the weighting functions. In this study, as a recently-developed heuristic approach, a multi-objective SFLA with constraints is adopted to search for the optimal weighting functions. In the proposed semi-active control, firstly, based on the Bouc–Wen model, the forward dynamic characteristics of the MR damper are investigated through a series of tensile and compression experiments. Secondly, the MR damper inverse model is developed with an adaptive-network-based fuzzy inference system (ANFIS) technique. Finally, the SFLA-optimized MSH control approach integrated with the ANFIS inverse model is used to suppress the structural vibration. The simulation results for a three-story building model equipped with an MR damper verify that the proposed semi-active control method outperforms fuzzy control and two passive control methods. Besides, with the proposed strategy, the changes in structural parameters and earthquake excitations can be satisfactorily dealt with.

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