Optimal Preview Control of Structural Vibrations Under Earthquake Excitations

Author(s):  
A. F. Shahrabi ◽  
G. Ahmadi

Active vibration control of structures under earthquake excitation has attracted considerable attention in the recent years. In this study, attention was given to optimal preview control methodology for protection of building with and without base isolation systems against earthquakes. A three-story building model was used and several earthquake records including El Centro, Mexico City and Tabas earthquake records were used as excitation. Acceleration and displacement responses of the structure with active preview control were evaluated and the results are compared with those for the unprotected buildings. It was shown that using properly designed active preview control systems can effectively reduce the acceleration transmitted to structures during a major earthquake. The study was repeated for a base isolated structure. It was shown that that the using the information obtain from the preview sensors in the active control strategy would improve the system performance significantly. The influence of the preview time on the system performance was also studied. It was found that the range of preview time needed for improved performance is quite small but depends on the frequency contend of the earthquake excitation.

Actuators ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 43 ◽  
Author(s):  
Manuel Braz César ◽  
João Paulo Coelho ◽  
José Gonçalves

A buildings resilience to seismic activity can be increased by providing ways for the structure to dynamically counteract the effect of the Earth’s crust movements. This ability is fundamental in certain regions of the globe, where earthquakes are more frequent, and can be achieved using different strategies. State-of-the-art anti-seismic buildings have, embedded on their structure, mostly passive actuators such as base isolation, Tuned Mass Dampers (TMD) and viscous dampers that can be used to reduce the effect of seismic or even wind induced vibrations. The main disadvantage of this type of building vibration reduction strategies concerns their inability to adapt their properties in accordance to both the excitation signal or structural behaviour. This adaption capability can be promoted by adding to the building active type actuators operating under a closed-loop. However, these systems are substantially larger than passive type solutions and require a considerable amount of energy that may not be available during a severe earthquake due to power grid failure. An intermediate solution between these two extremes is the introduction of semi-active actuators such as magneto–rheological dampers. The inclusion of magneto–rheological actuators is among one of the most promising semi-active techniques. However, the overall performance of this strategy depends on several aspects such as the actuators number and location within the structure and the vibration sensors network. It can be the case where the installation leads to a non-collocated system which presents additional challenges to control. This paper proposes to tackle the problem of controlling the vibration of a non-collocated three-storey building by means of a brain–emotional controller tuned using an evolutionary algorithm. This controller will be used to adjust the stiffness coefficient of a magneto–rheological actuator such that the building’s frame oscillation under earthquake excitation, is mitigated. The obtained results suggest that, using this control strategy, it is possible to reduce the building vibration to secure levels.


Author(s):  
Keigo Nakamura ◽  
Nanako Miura ◽  
Akira Sone

In this research, the focus is on the energy problem in active vibration control of a seismic isolation device using self-powered active control that regenerates electric power from kinetic energy of vibration system and uses it as control power. In recent years, it is proposed to install semi-active control or active control in an isolated structure to deal with seismic waves of various periods. However, since energy is required for control, there is a problem that the desired response reduction performance cannot be achieved when energy supply is interrupted at the time of a power outage. In our previous device, power is always given to the motor to control, thus power consumption is high. Therefore, the purpose of this research is to propose input method of control force that can reduce control power while keeping base isolation performance by classifying the role of the control force for each control phase and considering various combinations of input control force.


2018 ◽  
Vol 24 (22) ◽  
pp. 5391-5400 ◽  
Author(s):  
Yanping Yang ◽  
Dawei Zhang ◽  
Qing-Long Han

This paper investigates the networked active vibration control for a multi-degree-of-freedom structural system subject to modeling uncertainties, stochastic sensor faults, and earthquake excitations. By adopting a positive velocity feedback controller and introducing a communication network that produces proper network-induced delays and packet dropouts in the feedback control loop, the closed-loop system is first modeled by an uncertain stochastic system with a nonsmall interval time-varying input delay. Then a delay-dependent criterion is derived by employing a complete Lyapunov–Krasovskii functional such that the stochastic system with the proper nonzero input delay is stochastically stable with L2-gain performance, but unstable without delay. An iterative algorithm is presented to design the networked controller. A three-storey shear-beam building model subject to the El Centro 1940 earthquake is given to validate the proposed approach.


2018 ◽  
Vol 37 (1) ◽  
pp. 107-127 ◽  
Author(s):  
Muhammed Arif Şen ◽  
Mustafa Tinkir ◽  
Mete Kalyoncu

The control of vibration and displacement in structures under seismic excitation is very challenging, and designing a structural control system against disturbances has drawn great attention. This paper concentrates on implementing the bees algorithm to tune gains of traditional PID controller for active vibration control of a building-like structure with two floors under Northridge Earthquake excitation. Bees algorithm is a diverse method to ensure an efficient solution for optimisation of a controller according to customary trial-error design methods. The main aim of this study is optimisation of KP, KI and KD gains with bees algorithm in order to obtain a more effective PID controller to suppress vibrations of the floors during the earthquake excitation. After definition of the system and bees algorithm, PID controller offline tuned with bees algorithm using mathematical model of system. Moreover, the aim is to compare the performances of the BA with an existing optimisation method, genetic algorithm (GA), implemented on the system. The paper presents the experimental results that were obtained from the structure system to show the efficiency of the tuned PID controller. As a result, the performance and effectiveness of the tuned PID controller are investigated and verified experimentally. The displacements and accelerations of the floors and the cart are decreased considerably. The experimental responses of the system are given in graphical form.


2016 ◽  
Vol 84 ◽  
pp. 120-133 ◽  
Author(s):  
Athanasios A. Markou ◽  
Giuseppe Oliveto ◽  
Anastasia Athanasiou

1998 ◽  
Vol 120 (1) ◽  
pp. 104-110 ◽  
Author(s):  
D. Margolis

Active vibration control uses sensing and power actuators to attenuate vibrational energy due to external disturbances. Many of these systems are retrofitted into already existing passive ones. As a result allowable relative motions are prescribed, and this influences the performance of the active system. This paper exposes these limitations and shows realistic expectations for two excellent control strategies.


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