The flexible smart structure is broadly applied in various fields. In order to reduce the vibration of smart structures, a dual loop PD control strategy is proposed based on the Lagrangian dynamics mathematical modeli...
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ISBN:
(纸本)9783037858967
The flexible smart structure is broadly applied in various fields. In order to reduce the vibration of smart structures, a dual loop PD control strategy is proposed based on the Lagrangian dynamics mathematical modeling of the flexible system and a revision of the traditional lqr algorithm, the simulation and physical experiments show that the proposed approach is efficient in controlling and damping out the vibration and disturbance in flexible smart structure system.
The sealed,tuned liquid column gas damper （TLCGD） with gas-spring effect extends the frequency range of application and efficiently increases the modal structural *** tuned liquid column gas damper （ATLCGD） is dev...
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The sealed,tuned liquid column gas damper （TLCGD） with gas-spring effect extends the frequency range of application and efficiently increases the modal structural *** tuned liquid column gas damper （ATLCGD） is developed for the vibration control of plane asymmetric buildings subjected to earthquake excitation,improving the performance of the passive control *** active behaviour is obtained by adjusting the pressure at the end of the liquid column using a pressurised *** classical linear quadratic regulator （lqr） design is presented as a straightforward approach to optimal *** simulations indicate a significant vibration reduction of plane asymmetric buildings by active control within the strong motion of the dynamic response.
It is generally accepted that active control systems provide better structural performance when compared to their passive counterparts. On the other hand, the design of active control systems based on linear control t...
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It is generally accepted that active control systems provide better structural performance when compared to their passive counterparts. On the other hand, the design of active control systems based on linear control theory is highly dependent on the structural properties. For this reason, their performance is expected to be affected more severely by variations in structural properties compared to those of passive systems. These variations can occur due to nonlinear structural behavior, or even before that due to uncertainties in the estimation of these properties and in numerical modeling. The present work is an investigation of the dependency of various control systems used for supplemental energy dissipation to the changes in structural properties. For this purpose, the performance degradations of most common control systems are studied for structures entering their nonlinear response range. The considered control systems include active control using linear quadratic regulator algorithm and passive control using viscous fluid dampers and yielding devices. These control systems are optimized separately for linear and nonlinear structures by minimizing performance indices based on inter-story drift and absolute acceleration response. It is shown that among these control systems, viscous dampers are affected the least by the alteration of structural properties, which may further support their utilization contrary to the more costly active control systems. It is also shown that the amount of performance degradation depends on the selected structural performance index, and more importantly, the severity of the earthquake excitation.
In this paper, an attempt is made to examine a new method for designing and applying the active vibration control system to improve building performance under mainshock-aftershock sequences. In this regard, three diff...
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In this paper, an attempt is made to examine a new method for designing and applying the active vibration control system to improve building performance under mainshock-aftershock sequences. In this regard, three different structures are considered;5-, 10-, and 15-story buildings. Seven mainshock-aftershock sequences are selected from the Iranian accelerogram database for analyzing the structures. By implementing an advanced two-step optimization method, buildings equipped with the active vibration control system (linear-quadratic regulator (lqr) algorithm) are designed to withstand all events of mainshock-aftershock sequences. In the first optimization step, a multi-objective optimization with the genetic algorithm is performed and a set of optimal Pareto front results is obtained. In the next step, the life-cycle cost of each optimal design sample of the Pareto front is calculated by considering the cumulative damage and the design sample with the minimum cost is selected as a final optimal property. The results prove that the active vibration control system is capable of reducing structural responses, including acceleration, drift, and residual drift under mainshock-aftershock sequences, and consequently the life-cycle cost of buildings, especially the taller ones. In addition, obtaining the building design variables (story stiffness and yielding force) and active lqr algorithm properties simultaneously leads to a slightly softer final building model than the conventional structure designed by the common building design code. Moreover, it is revealed that, by considering the aftershocks, the building life-cycle cost increases significantly.
Nonstructural damage, usually predominates in buildings subjected to low to moderate seismic intensities and contributes significantly to business interruption and economic losses. It promotes a rapidly growing need f...
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Nonstructural damage, usually predominates in buildings subjected to low to moderate seismic intensities and contributes significantly to business interruption and economic losses. It promotes a rapidly growing need for experimental research and qualification of various types of nonstructural elements in buildings in the recent decades. To provide a novel option of experimentally simulating the realistic boundary conditions for various nonstructural elements in labs, we developed the Nonstructural Element Simulator on Shake Table (NEST), a passively controlled three-layer substructural testbed driven by existing shake tables. This paper presents the first experimental implementation of NEST on a challenging 42-story archetype tall building. The dynamic properties of the substructure were tuned to adapt the archetype building and the required shake table motions were solved as a reverse problem by an open-loop control algorithm. The test results proved the capability of NEST to replicate the history responses of the target floors in the archetype building under either recorded earthquake ground motion or artificial loading protocols for qualification purposes. In all cases, the synthetic relative error in the floor accelerations and the inter-story drift within the frequency range of interest was less than 5% in the numerical domain and less than 30% in the physical realization. The seismic responses of a variety of nonstructural elements to the substructural motions show that, in the mid-story of the archetype tall building, the ceiling sustained minimum damage because of the small floor acceleration while the indoor contents slid significantly and even overturned.
A new active tuned liquid column damper is developed for seismic vibration control of structures by employing the configuration of the compliant liquid column damper (CLCD). This control system is referred to as the a...
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A new active tuned liquid column damper is developed for seismic vibration control of structures by employing the configuration of the compliant liquid column damper (CLCD). This control system is referred to as the active CLCD or ACLCD. The theoretical model of the proposed ACLCD is presented, in which the controller is designed first by the linear quadratic regulator (lqr) algorithm. The design procedure developed for the ACLCD is illustrated both for an example flexible structure and for an example stiff structure, subjected to a recorded accelerogram input. The optimal design of the passive CLCDs is also presented, to provide the basis for the choice of the damper parameters of the ACLCD. The optimum control parameters of the ACLCD are evaluated with the objective of minimizing the displacement response of the structure while maintaining the stability of response reduction and satisfying the constraints on peak liquid and whole damper displacements. A multiresolution-based wavelet controller (Wlqr) is also designed for the ACLCD, achieving structural displacement response reductions comparable to that obtained from the conventional lqr controller but with the application of comparatively lower control forces. The enhanced effectiveness of the ACLCD over that of the passive CLCD is demonstrated through a time domain study. The performances of the lqr- and Wlqr-based control strategies are compared, in terms of both structural response reduction and requirement of peak control force magnitudes, for the design input as well as under excitation variability.
An experimental analysis of the influence of a creep phenomenon on the performance of a control system of a piezoelectric cantilever actuator is the subject of the paper. The controlled piezoelectric actuator was comp...
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ISBN:
(纸本)9798350350708;9798350350715
An experimental analysis of the influence of a creep phenomenon on the performance of a control system of a piezoelectric cantilever actuator is the subject of the paper. The controlled piezoelectric actuator was composed of three layers: one carrier layer made of aluminum type 1050 and two piezoelectric layers made of macro fiber composites (MFC) patches. A linear lqr algorithm with integral action was used in the control system. Based on laboratory experiments, it was noticed that the selection of weights in the Q matrix has a significant impact on avoiding the creep effects in the control system.
The High-Order Flexible Rectilinear Plant can verify advanced control theory, such as Optimal Control, Fuzzy Control, Adaptive Control, Robust control, Neural Network Control and so on. The biggest advantage of the pl...
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ISBN:
(纸本)9789881563897
The High-Order Flexible Rectilinear Plant can verify advanced control theory, such as Optimal Control, Fuzzy Control, Adaptive Control, Robust control, Neural Network Control and so on. The biggest advantage of the plant is that it can implement real-time control for the system through two kinds of operating environment. One is that establishing model in the Simulink environment, because the system provides a module which can communicate with the device, lots of algorithms can be implemented by using this module. The other is that programming C code in the ECP environment which is provided by ECP company of the United States. Under the two environments, comparing the control effect of PID algorithm and lqr algorithm by means of simulation and experiment. The result displays that the lqr optimal control is better than PID control obviously here.
This paper examines the effectiveness of the Active Tuned Liquid Column Gas Damper (ATLCGD) when equipped on the plan-asymmetric structures subjected to earthquake excitation. The active behaviour is obtained by adjus...
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ISBN:
(纸本)9780878492060
This paper examines the effectiveness of the Active Tuned Liquid Column Gas Damper (ATLCGD) when equipped on the plan-asymmetric structures subjected to earthquake excitation. The active behaviour is obtained by adjusting the pressure at the end of the liquid column using a pressurised reservoir. The classical linear quadratic regulator (lqr) control strategy is applied to determine optimal control force of the ATLCGDs. A case study of a four-storey asymmetric structure is conducted to illustate excellent control efficacy of the proposed active TLCGD control system.
In view of the nonlinear characteristic of the pendulum system, the paper applies the lqr algorithm to control the cart position and the pendulum pole angle simultaneously. In order to show the control effect lively, ...
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ISBN:
(纸本)9783037852491
In view of the nonlinear characteristic of the pendulum system, the paper applies the lqr algorithm to control the cart position and the pendulum pole angle simultaneously. In order to show the control effect lively, the paper proposes the realization plan which constructing the dynamic and observed pendulum control system by configuration software. The results of simulation computation and configuration design demonstrate that the plan can proves the application value of the lqr algorithm in the pendulum control system and achieves fine teaching effect in the actual teaching process.
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