scholarly journals Comparative Study of Different Active Control Systems of High Rise Buildings under Seismic Excitation

2019 ◽  
Author(s):  
Mohamed Hechmi El Ouni ◽  
Nabil Ben Kahla ◽  
Mohd Ahmed ◽  
Saiful Islam ◽  
Hamdi Ayed ◽  
...  
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Force Feedback ◽  
Active Vibration Control ◽  
Force Sensor ◽  
Point Of View ◽  
Seismic Excitation ◽  
Displacement Sensor ◽  
Control Effort ◽  
Bracing System

Large number of active vibration control systems existing in the literature has brought lot of confusion for engineers and junior researchers. This study deals with the comparison of different active control systems of a 20-storey building under seismic excitation for three control devices: Active Mass Damper (AMD), Active Bracing System (ABS) and Connected Building Control (CBC). Two different control configurations are considered to add active damping to the building. The first one employs force actuator and displacement sensor and is examined with first and second order Positive Position Feedback, Lead compensators and Direct Velocity Feedback. The second configuration employs a displacement actuator collocated with a force sensor and an Integral Force Feedback control law. A total number of 15 control cases are compared from the point of view of stability, robustness, performance and control effort.

Frequency Shaped Semi-Active Control for Magnetorheological Fluid-Based Vibration Control Systems

2013 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Model Parameters ◽  
Mr Fluid ◽  
Control Current ◽  
Active Vibration

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.

A Comparative Study and Analysis of Semi-Active Vibration-Control Systems

2002 ◽  
Vol 124 (4) ◽  
pp. 593-605 ◽  
Author(s):  
Nader Jalili
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Energy Requirement ◽  
Active Vibration Control ◽  
Parameter Tuning ◽  
Practical Implementation ◽  
Control Effort ◽  
Theoretical Concepts ◽  
Practical Applications ◽  
Active Vibration

Semi-active (SA) vibration-control systems are those which otherwise passively generated damping or spring forces are modulated according to a parameter tuning policy with only a small amount of control effort. SA units, as their name implies, fill the gap between purely passive and fully active vibration-control systems and offer the reliability of passive systems, yet maintain the versatility and adaptability of fully active devices. During recent years there has been considerable interest towards practical implementation of these systems for their low energy requirement and cost. This paper briefly reviews the basic theoretical concepts for SA vibration-control design and implementation, and surveys recent developments and control techniques for these systems. Some related practical applications in vehicle suspensions are also presented.

Transmissibilities of Two-Degree-of-Freedom Systems for Semi-Active Vibration Control

Aerospace ◽  
2006 ◽  
Author(s):  
H. F. Lam ◽  
W. H. Liao
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Transfer Functions ◽  
Active Vibration Control ◽  
Degree Of Freedom ◽  
Reference Systems ◽  
Active Systems ◽  
Active Vibration ◽  
Equivalent Systems ◽  
Two Degree Of Freedom

Transmissibilities for two-degree-of-freedom (2DoF) passive systems have been extensively investigated in the past. However, for semi-active control systems, the transmissibilities are rarely analyzed. The expressions of non-dimensional transmissibilities for the semi-active control systems are not found. There are no closed-form transfer functions for general semi-active control systems. The control algorithms for semi-active systems need to be specified first. Therefore, three reference systems (skyhook, groundhook, and their hybrid) are proposed. These equivalent systems are the references for the semi-active control systems to achieve. In this paper, the 2DoF skyhook, groundhook and hybrid systems for semi-active control are studied. The displacement and acceleration transmissibilities of those three reference systems are formulated and analyzed. Their transmissibilities are also compared with the passive system. Each of reference systems is classified as Ideal and Non-Ideal systems. The differences between the Ideal and Non-Ideal systems are also discussed. The optimal systems and their corresponding parameters are identified.

scholarly journals Modified Independent Modal Space Control Method for Active Control of Flexible Systems

1989 ◽  
Vol 203 (2) ◽  
pp. 103-112 ◽  
Author(s):  
A Baz ◽  
S Poh ◽  
P Studer
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Optimal Placement ◽  
Flexible Systems ◽  
Time Sharing ◽  
Active Vibration ◽  
Modal Space

A modified independent modal space control (MIMSC) method is developed for designing active vibration control systems for large flexible structures. The method accounts for the interaction between the controlled and residual modes. It also incorporates optimal placement procedures for selecting the optimal locations of the actuators in the structure in order to minimize the structural vibrations as well as the actuation effort. The MIMSC method relies on an important feature which is based on ‘time sharing’ of a small number of actuators, in the modal space, to control effectively a large number of modes. Numerical examples are presented to illustrate the application of the method to generic flexible systems. The obtained results suggest the potential of the devised method in designing efficient active control systems for large flexible structures.

Optimal Sensor and Actuator Placement for Active Vibration Control Systems

2012 ◽  
Author(s):  
Britta Späh ◽  
Rudolf Sebastian Schittenhelm ◽  
Stephan Rinderknecht
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Vibration Control ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Sensors And Actuators ◽  
Control Effort ◽  
Control Objective ◽  
Optimal Feed ◽  
Actuator Placement

Locations of sensors and actuators have major impact on the characteristics of control systems. In this paper a procedure for sensor and actuator placement for vibration control systems is presented. Two different performance criteria are used in order to find optimal positions for the system under consideration. One is considering observability and controllability only, the other one includes knowledge about a disturbance and the control objective. Both criteria are applied to a clamped plate resulting in different optimal sensor and actuator positions. The resulting configurations are investigated by comparison of optimal feed forward and H∞ feedback control of the system with identical disturbances and control objectives but different sensor and actuator positions. The required control effort and achieved amplitude reduction are employed to rate the different performance criteria that were used to determine the sensor and actuator positions. It is shown that, by placing sensors and actuators on the basis of an adequate performance criterion, increased control performance in terms of amplitude reduction per control effort is achieved.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals The Application of an Impedance-Passivity Controller in Haptic Stability Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1618
Author(s):  
Ping-Nan Chen ◽  
Yung-Te Chen ◽  
Hsin Hsiu ◽  
Ruei-Jia Chen
Keyword(s):  
Control Systems ◽  
Force Feedback ◽  
Training System ◽  
Considerable Time ◽  
Virtual Training ◽  
Control Gain ◽  
Negative Damping ◽  
The Stability ◽  
Time Required ◽  
Stable Control

This paper proposes a passivity theorem on the basis of energy concepts to study the stability of force feedback in a virtual haptic system. An impedance-passivity controller (IPC) was designed from the two-port network perspective to improve the chief drawback of haptic systems, namely the considerable time required to reach stability if the equipment consumes energy slowly. The proposed IPC can be used to achieve stability through model parameter selection and to obtain control gain. In particular, haptic performance can be improved for extreme cases of high stiffness and negative damping. Furthermore, a virtual training system for one-degree-of-freedom sticking was developed to validate the experimental platform of our IPC. To ensure consistency in the experiment, we designed a specialized mechanical robot to replace human operation. Finally, compared with basic passivity control systems, our IPC could achieve stable control rapidly.

The Control of the Eye's Intrinsic Muscles: A Multivariable Optimum Performance Control System

1968 ◽  
Vol 1 (8) ◽  
pp. T.129-T.132 ◽  
Author(s):  
F. M. Toates
Keyword(s):  
Control System ◽  
Control Systems ◽  
Pupil Diameter ◽  
Control Model ◽  
Point Of View ◽  
Theoretical Point ◽  
Pupil Control ◽  
Performance Control ◽  
A Value ◽  
Intrinsic Muscles

The reciprocal interaction between the accommodation and pupil control systems of the human eye is examined from a theoretical point of view. The system, which is responsible for maintaining pupil diameter at a value which is a compromise between conflicting requirements, is represented by a control model, and is considered in terms of the concept of a performance index.

Structural Analysis of an Offshore Jacket Model Under Seismic Excitation

2008 ◽  
Author(s):  
Helder J. D. Correia ◽  
Anto´nio C. Mendes ◽  
Carlos A. F. S. Oliveira
Keyword(s):  
Point Of View ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Model Structure ◽  
Structural Members ◽  
Jacket Structures ◽  
Reaction Forces ◽  
Nodal Displacements ◽  
Good Agreement

In the present work the action of earthquakes upon offshore jacket structures is analysed by means of ADINA software. Our case-study refers to an existing model structure, previously constructed at the Laboratory of Fluid Mechanics of UBI, which has been analysed from the hydrodynamic point of view — Mendes et al. [1, 2]. The seismic excitation will be imposed at the base of this model structure, with frequencies and amplitudes corresponding to actual earthquake conditions transposed to the model scale of 1:45. The FEM software is utilised to calculate the natural frequencies of the model and to obtain stresses at selected members, as well as their nodal displacements. Our purpose is to quantify maximum stresses occurring in critical structural members and to verify the survivability criterion. The predictions of the numerical model, in terms of the reaction forces at the base and acceleration at the top of the structure, are then correlated with the experimental measurements performed when the model structure is excited in an especially designed shaking table (Correia [3]), revealing a good agreement between both results.

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