scholarly journals Optimum Allocation of MR Dampers within Semi-Active Control Strategies of Three-Degree-of-Freedom Systems

2016 ◽  
Vol 4 (4) ◽  
pp. 45
Author(s):  
Omar Mahmoud Elmeligy ◽  
M. H. M. Hassan
Keyword(s):  
Fuzzy Logic ◽  
Active Control ◽  
Structural Control ◽  
Control Strategies ◽  
Structural Response ◽  
Degree Of Freedom ◽  
Maximum Displacement ◽  
Maximum Acceleration ◽  
Mr Dampers ◽  
Three Degree Of Freedom

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.

Semiactive Control of Structural Vibrations

1993 ◽  
Author(s):  
W. N. Patten ◽  
H. C. Wu ◽  
W. Yan ◽  
R. L. Sack ◽  
C. C. Kuo ◽  
...  
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Control Strategies ◽  
Structural Response ◽  
Semiactive Control ◽  
Hydraulic Actuator ◽  
Limit States ◽  
Loop Control ◽  
Mechanical Devices ◽  
Control Forces

Abstract Structural control can be used to mitigate dynamic structural response and prevent structures from reaching their limit states. Typical active vibration systems utilize large electric motors, and expensive hydraulic pumping equipment to provide force inputs to a structure during a dynamic event. The work here explores the effectiveness of low power, inexpensive semi-active control hardware to provide vibration attenuation, for structures. While there are a number of electro-mechanical devices that might provide semi-active control forces, the investigation here analyzed the use of an automatically adjustable hydraulic actuator (i.e., a shock absorber). The variation in damping characteristics is accomplished by using variable orificing. While semi-active hydraulic actuators are a relatively cheap means of providing smart damping for a structure, the development of effective closed loop control strategies for these devices is not a completely resolved issue. The paper develops a dynamic model of a semi-active actuator. Two inner loop controllers are then suggested, for the operation of the actuator. The control of a simple structure is then simulated. The paper closes with a comparison of the performances between a semi-active (clipped optimal) control and active control of a three story structure that is subject to an earthquake.

Structural Control Considering Time Delay Effect

1985 ◽  
Vol 9 (4) ◽  
pp. 224-227 ◽  
Author(s):  
Mohamed Abdel-Rohman
Keyword(s):  
Time Delay ◽  
Active Control ◽  
Theoretical Consideration ◽  
Structural Control ◽  
Control Mechanism ◽  
Structural Response ◽  
Delay Effect ◽  
Numerical Example ◽  
Control Forces ◽  
Time Delay Effect

The time delay between measuring the structural response, and applying the designed active control forces may affect the controlled response of the structure if not taken into consideration. In this paper it is shown how to design the control forces to compensate for the delay effect. It is also shown that the time delay effect can be used as a criterion to judge the effectiveness of the proposed control mechanism. As an illustration of the theoretical consideration, a numerical example in which a tall building is controlled by means of active tendons is presented.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

A 3-ṞPR Parallel Mechanism With Singularities That are Self-Motions

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
Novona Rakotomanga ◽  
Ilian A. Bonev
Keyword(s):  
Parallel Mechanism ◽  
Control Strategies ◽  
Joint Space ◽  
Degree Of Freedom ◽  
Parallel Mechanisms ◽  
Active Joint ◽  
Cartesian Space ◽  
Three Degree Of Freedom

The Cartesian workspace of most three-degree-of-freedom parallel mechanisms is divided by Type 2 (also called parallel) singularity surfaces into several regions. Accessing more than one such region requires crossing a Type 2 singularity, which is risky and calls for sophisticated control strategies. Some mechanisms can still cross these Type 2 singularity surfaces through “holes” that represent Type 1 (also called serial) singularities only. However, what is even more desirable is if these Type 2 singularity surfaces were curves instead. Indeed, there exists at least one such parallel mechanism (the agile eye) and all of its singularities are self-motions. This paper presents another parallel mechanism, a planar one, whose singularities are self-motions. The singularities of this novel mechanism are studied in detail. While the Type 2 singularities in the Cartesian space still constitute a surface, they degenerate into lines in the active-joint space, which is the main result of this paper.

Nonlinear Structural Control Using Magnetorheological Damper

2015 ◽  
pp. 211-244
Author(s):  
Shaikh Faruque Ali ◽  
Ananth Ramaswamy
Keyword(s):  
Structural Control ◽  
Structural Response ◽  
Geometric Approach ◽  
Magnetorheological Damper ◽  
Control Algorithms ◽  
Rule Base ◽  
Numerical Comparison ◽  
Mr Dampers ◽  
Logic Control ◽  
Numerical Studies

This chapter provides an introduction to semi active control of base isolated buildings using magnetorheological (MR) dampers. Recently developed nonlinear control algorithms are discussed. First a fuzzy logic control (FLC) is designed to decide how much voltage is required to be supplied to the MR damper for a desired structural response. The FLC is optimized using micro genetic algorithm. A novel geometric approach is developed to optimize the FLC rule base. Experiments are undertaken to access the efficacy of the optimal FLC. Secondly the chapter develops two model based control algorithms based on dynamic inversion and integrator backstepping approaches. A three storey base isolated building is used for experimental and numerical studies. A numerical comparison is shown with clipped optimal control.

Optimized Fuzzy Logic Controller for Semi-Active Control of Buildings Using Particle Swarm Optimization

2011 ◽  
Vol 255-260 ◽  
pp. 2505-2509 ◽  
Author(s):  
Mohammadreza Ostadali Makhmalbaf ◽  
Mohammad Amin Tutunchian ◽  
Masoud Zabihi Samani
Keyword(s):  
Fuzzy Logic ◽  
Particle Swarm Optimization ◽  
Active Control ◽  
Fuzzy Logic Controller ◽  
Particle Swarm ◽  
Engineering Structures ◽  
Swarm Optimization ◽  
Mr Dampers ◽  
Control Devices ◽  
Current Monitoring

Control devices can be used in structures to attenuate undesirable vibration on engineering structures. In order to mitigate the response of structures during the earthquakes and high intensity winds semi active control has been widely used. Semi-active control need less energy in compare with active control. So they are more reliable and more effective in mitigating the effects of earthquakes. MR damper are semi active control devices that are managed by sending external voltage supply. The inducing current monitoring of MR dampers are intelligently managed by fuzzy logic control (FLC). Validation of fuzzy logic controller that is optimized by a particle swarm optimization(PSO) is pursued in this study. Finally, optimal fuzzy logic controller is identified and validated through numerical simulation for seismic excitation. In 3-storey benchmark building, results showed that optimized fuzzy logic controller was robust and effective in reduction of both displacement and acceleration responses.

Impact Damper With Granular Materials for Multibody System

1996 ◽  
Vol 118 (1) ◽  
pp. 95-103 ◽  
Author(s):  
I. Yokomichi ◽  
Y. Araki ◽  
Y. Jinnouchi ◽  
J. Inoue
Keyword(s):  
Granular Materials ◽  
Equations Of Motion ◽  
Degree Of Freedom ◽  
Mode Shapes ◽  
Maximum Displacement ◽  
Impact Damper ◽  
Particle Bed ◽  
Modal Mass ◽  
Three Degree Of Freedom ◽  
The Impact

An efficient impact damper consists of a bed of granular materials moving in a container mounted on a multibody vibrating system. This paper deals with the damping characteristics of a multidegree-of-freedom (MDOF) system that is provided with the impact damper when the damper may be applied to any point of the system. In the theoretical analysis, the particle bed is assumed to be a mass which moves unidirectionally in a container, and collides plastically with its end. Equations of motion are developed for an equivalent single-degree-of-freedom (SDOF) system and attached damper mass with use made of the normal mode approach. The modal mass is estimated such that it represents the equivalent mass on the point of maximum displacement in each of the vibrating modes. The mass ratio is modified with the modal vector to include the effect of impact interactions. Results of the analysis are applied to the special case of a three-degree-of-freedom (3DOF) system, and the effects of the damper parameteres including mode shapes and damper locations are determined. A digital model is also formulated to simulate the damped motion of the physical system.

Nonlinear Structural Control Using Magnetorheological Damper

2013 ◽  
pp. 300-332
Author(s):  
Shaikh Faruque Ali ◽  
Ananth Ramaswamy
Keyword(s):  
Structural Control ◽  
Structural Response ◽  
Geometric Approach ◽  
Magnetorheological Damper ◽  
Control Algorithms ◽  
Rule Base ◽  
Numerical Comparison ◽  
Mr Dampers ◽  
Logic Control ◽  
Numerical Studies

This chapter provides an introduction to semi active control of base isolated buildings using magnetorheological (MR) dampers. Recently developed nonlinear control algorithms are discussed. First a fuzzy logic control (FLC) is designed to decide how much voltage is required to be supplied to the MR damper for a desired structural response. The FLC is optimized using micro genetic algorithm. A novel geometric approach is developed to optimize the FLC rule base. Experiments are undertaken to access the efficacy of the optimal FLC. Secondly the chapter develops two model based control algorithms based on dynamic inversion and integrator backstepping approaches. A three storey base isolated building is used for experimental and numerical studies. A numerical comparison is shown with clipped optimal control.

APPLICATION OF FUZZY CONTROL THEORY IN ACTIVE CONTROL OF STRUCTURES

1996 ◽  
Vol 04 (03) ◽  
pp. 255-274 ◽  
Author(s):  
KEN YEH ◽  
WEILING CHIANG ◽  
DERSHIN JUANG
Keyword(s):  
Fuzzy Control ◽  
Control Theory ◽  
Active Control ◽  
Structural Control ◽  
Fuzzy Controller ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Active Structural Control ◽  
Band Pass ◽  
Control Methodology

The purpose of this paper is to apply fuzzy control theory in active structural control. A single-degree-of-freedom (SDOF) structure is used to develop the basic approach. The approach is then extended to multi-degree-of-freedom (MDOF) structures with the usage of weighted displacement and weighted velocity. A band-pass white noise or large amount of earthquake records are used as excitations to the structures to calculate the normalized displacements and velocities for obtaining the range of weighted displacements and velocities. Several examples are utilized to demonstrate the feasibility of fuzzy control methodology. It is shown that the fuzzy controller can achieve satisfactory results in the application of active control of structures and the feasibility is verified.

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