Control Algorithms for Semi-Active Structural Systems: Do they Really Matter?

2008 ◽  
Vol 56 ◽  
pp. 182-187
Author(s):  
Antonio Occhiuzzi
Keyword(s):  
Control System ◽  
Control Systems ◽  
Active Control ◽  
Structural Control ◽  
Control Algorithm ◽  
Scientific Literature ◽  
Control Algorithms ◽  
Control Law ◽  
Structural Systems ◽  
Active Structural Control

Control algorithms for semi-active structural control system found in the scientific literature often rely on the choice of several parameters included in the control law. The present paper shows the preliminary conclusions of a study aiming to explain the weak dependency of the response reduction associated to semi-active control systems on the particular choice of the control algorithm adopted, provided that the relevant parameters of any control law be properly tuned.

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.

Semi-Active Control of Structural Systems Aiming to Approximate the Performance of the Targeted Active Control Law: Output Emulation Approach

2013 ◽  
Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda
Keyword(s):  
Control System ◽  
Active Control ◽  
Variable Parameter ◽  
Control Law ◽  
Structural Systems ◽  
Control Force ◽  
Control Performance ◽  
Control Devices ◽  
Active Control System ◽  
Control Output

As a method for semi-active control of structural systems, the active-control-based method that emulates the control force of a targeted active control law by semi-active control devices has been studied. In the active-control-based method, the semi-active control devices are not necessarily able to generate the targeted active control force because of the dissipative nature of those devices. In such a situation, the meaning of the targeted active control law becomes unclear in the sense of the control performance achieved by the resulting semi-active control system. In this study, a new semi-active control strategy that approximates the control output (not the control force) of the targeted active control is proposed. The variable parameter of the semi-active control device is selected at every time instant so that the predicted control output of the semi-active control system becomes close to the corresponding predicted control output of the targeted active control as much as possible. Parameters of the targeted active control law are optimized in the premise of the above “output emulation” strategy so that the control performance of the semi-active control becomes good and the “error” of the achieved control performance between the targeted active control and the semi-active control becomes small.

scholarly journals Hybrid Electromagnetic Shunt Damper for Vibration Control

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ahmad Paknejad ◽  
Guoying Zhao ◽  
Simon Chesné ◽  
Arnaud Deraemaeker ◽  
Christophe Collette
Keyword(s):  
Control System ◽  
Power Consumption ◽  
Control Systems ◽  
Active Control ◽  
Hybrid Control ◽  
Current Source ◽  
Voltage Source ◽  
Control Law ◽  
Electromagnetic Devices ◽  
Hybrid Control System

Abstract It has been shown that shunting electromagnetic devices with electrical networks can be used to damp vibrations. These absorbers have however limitations that restrict the control performance, i.e., the total damping of the system and robustness versus parameter variations. On the other hand, the electromagnetic devices are widely used in active control techniques as an actuator. The major difficulty that arises in practical implementation of these techniques is the power consumption required for conditioners and control units. In this study, robust hybrid control system is designed to combine the passive electromagnetic shunt damper with an active control in order to improve the performance with low power consumption. Two different active control laws, based on an active voltage source and an active current source, are proposed and compared. The control law of the active voltage source is the direct velocity feedback. However, the control law of the active current source is a revisited direct velocity feedback. The method of maximum damping, i.e., maximizing the exponential time-decay rate of the response subjected to the external impulse forcing function, is employed to optimize the parameters of the passive and the hybrid control systems. The advantage of using the hybrid control configuration in comparison with purely active control system is also investigated in terms of the power consumption. Besides these assets, it is demonstrated that the hybrid control system can tolerate a much higher level of uncertainty than the purely passive control systems.

Semi-Active Control of Structural Systems With an Output Emulation Method Based on a Quadratic Error Function

2015 ◽  
Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda
Keyword(s):  
Control System ◽  
Active Control ◽  
Control Method ◽  
Error Function ◽  
Pole Placement ◽  
Control Law ◽  
Structural Systems ◽  
Quadratic Error ◽  
Active Control System ◽  
Active Control Method

A semi-active control method based on a controlled output of a targeted active control law is proposed in the study. As a conventional method, a semi-active control law based on the targeted active control input, e.g., a clipped optimal control and its related methods, is widely used for the vibration control of structural systems. In the present study, on the other hand, the controlled output of the targeted active control law is used as the reference of the semi-active control. The semi-active control strategy is referred to as “output emulation approach” and the authors showed a method based on the output emulation approach based on the predicted controlled output by assuming the targeted active control as the LQ optimal control law in the previous study. In this paper, a new output emulation semi-active control method with a quadratic error function between the controlled output signal of the semi-active control system and that of the targeted active control system. The semi-active control law minimizing the quadratic error function is obtained as a bang-bang type switching of the variable damping coefficient of the semi-active control device. The targeted active control law is defined as a state-space control with a constraint on the closed-loop pole placement. Design parameters to determine the region of the pole placement of the targeted active control system are adjusted so that the semi-active control based on the proposed output emulation approach is optimized. The effectiveness of the proposed approach is shown with a simulation example.

Servo Control Strategy of Single Axis Shaking Table in Active Structural Control System

2011 ◽  
Vol 58-60 ◽  
pp. 2446-2449
Author(s):  
Zhi Yong Qu ◽  
Zheng Mao Ye
Keyword(s):  
Control System ◽  
Structural Control ◽  
Control Algorithm ◽  
Servo Control ◽  
Shaking Table ◽  
Hydraulic Actuator ◽  
Feed Forward Control ◽  
Active Structural Control ◽  
Actuation System ◽  
Proposed Model

The purpose of this paper is to develop an approach to improve the tracking characteristics of a single axis shaking table actuation system, which is used in active structural control system. Firstly, the process of constructing analytical model of servo-hydraulic actuation system is presented. The proposed model, in the form of the total shaking table transfer function, accounts for the specific physical characteristics of the single axis shaking table. Due to low natural frequency and small hydraulic actuator damping, the single axis shaking table cannot meet the experimental requirement Therefore, three states feedback and three state feed-forward control algorithm based on pole-assignment principle is applied to extend the acceleration bandwidth. Lastly, the shaking table experiments are tested and the experimental results indicate that the controller is effective and reliable.

Design Method of Semi-Active Control Systems Minimizing the Error Between the Controlled Signals of the Semi-Active and its Reference Active Control Systems

2017 ◽  
Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Output Signal ◽  
Error Function ◽  
Quadratic Function ◽  
Control Law ◽  
Lyapunov Matrix ◽  
Active Control System

We propose a semi-active vibration control method of structural systems based on the output emulation approach. In the output emulation approach, the semi-active control law is obtained so that the controlled output signal of the semi-active control system is similar to that of the reference active control system. The reference active control system is a virtual control system employing the actuator for vibration control and achieves the ideal control performance. Because the constraints of the semi-active control comes from the inherent dissipative characteristics of semi-active control devices a certain amount of the error of the controlled output signals between the semi-active and its reference active control system is unavoidable. To realize the semi-active control system based on the output emulation approach, i.e., the semi-active control system whose controlled output signal is similar to that of the reference active control system, the semi-active control law in the present study is obtained for minimizing an error function related to the controlled output. The error function is defined as a quadratic function on the output signal of the error between the semi-active and its reference active control systems and the Lyapunov matrix. The control characteristics of the reference active control law and free parameters in the Lyapunov matrix are searched with a boot-strap optimization algorithm for the optimal semi-active control system. Some simulation results are shown to claim the effectiveness.

Effect of Response Related Weighting Matrices on Performance of Active Control Systems for Nonlinear Frames

2017 ◽  
Vol 17 (03) ◽  
pp. 1750030
Author(s):  
Mohtasham Mohebbi ◽  
Abdolreza Joghataie ◽  
Hamed Rasouli Dabbagh
Keyword(s):  
Control System ◽  
Control Systems ◽  
Active Control ◽  
Structural Response ◽  
Control Law ◽  
Control Force ◽  
Online Measurements ◽  
Active Control System ◽  
Distributed Genetic Algorithm ◽  
Response Feedback

In this paper, the effect of various arrangements of displacement, velocity and acceleration related weighting matrices on the performance of active control systems on nonlinear frames has been studied. Different arrangements of weighting matrices and feedback combinations of the response have been considered to design the active controllers using a single actuator for reducing the response of an eight-storey bilinear hysteretic frame under white noise excitations. The nonlinear Newmark-based instantaneous optimal control algorithm has been used, where the distributed genetic algorithm (DGA) is employed to determine the proper set of weighting matrices. For each set of feedback and weighting matrices, the active control system has been designed with the optimal weights determined. Here, the objective is to minimize the maximum control force required to reduce the maximum structural drift to a value below the desired level. The numerical results of simulation show that, for the cases studied, the use of different arrangements of weighting matrices in the proposed method for the performance index of the active control law has no significant impact on the performance of the active control system. However, the type of response feedback combination included in the control law considerably affects the performance, and the controllers designed based on velocity feedback have been found to be more effective. It was also shown that for all the weight-cases, using the full feedback of response can lead to design controllers that require minimum control force to reduce the structural response with more online measurements. The robustness of the designed controllers for different weighting matrices arrangements and feedback combinations has also been tested under a number of real earthquake excitations with the results discussed.

scholarly journals Integrated Design of Smart Structures

2008 ◽  
Vol 56 ◽  
pp. 127-136 ◽  
Author(s):  
G.P. Cimellaro ◽  
Tsu Teh Soong ◽  
A.M. Reinhorn
Keyword(s):  
Control System ◽  
Control Systems ◽  
Active Control ◽  
Structural Control ◽  
Integrated Design ◽  
The Other ◽  
Simultaneous Optimization ◽  
Structural Performance ◽  
Control Research ◽  
Control Devices

Much of structural control research and applications in civil engineering have been concerned with structures equipped with passive, hybrid, or active control devices in order to enhance structural performance under extraordinary loads. In most cases, the structure and the control system are individually designed and optimized. On the other hand, an exciting consequence of structural control research is that it also opens the door to new possibilities in structural forms and configurations, such as lighter buildings or bridges with longer spans without compromising on structural performance. Moreover, this can only be achieved through integrated design of structures with control elements as an integral part. This paper addresses the integrated design of structures with imbedded control systems and devices. Simultaneous optimization of such controlled structures is considered, showing that new structural forms and configurations can be achieved through integrated design.

Optimal Control of Nonlinear Structures

1988 ◽  
Vol 55 (4) ◽  
pp. 931-938 ◽  
Author(s):  
J. N. Yang ◽  
F. X. Long ◽  
D. Wong
Keyword(s):  
Optimal Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Open Loop ◽  
Control Algorithms ◽  
Nonlinear Structures ◽  
Open Loop Control ◽  
Loop Control ◽  
Optimal Control Algorithms

Three optimal control algorithms are proposed for reducing oscillations of flexible nonlinear structures subjected to general stochastic dynamic loads, such as earthquakes, waves, winds, etc. The optimal control forces are determined analytically by minimizing a time-dependent quadratic performance index, and nonlinear equations of motion are solved using the Wilson-θ numerical procedures. The optimal control algorithms developed for applications to nonlinear structures are referred to as the instantaneous optimal control algorithms, including the instantaneous optimal open-loop control algorithm, instantaneous optimal closed-loop control algorithm, and instantaneous optimal closed-open-loop control algorithm. These optimal algorithms are computationally efficient and suitable for on-line implementation of active control systems to realistic nonlinear structures. Numerical examples are worked out to demonstrate the applications of these optimal control algorithms to nonlinear structures. In particular, control of structures undergoing inelastic deformations under strong earthquake excitations are illustrated. The advantage of using combined passive/active control systems is also demonstrated.

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

2017 ◽  
Vol 140 (2) ◽  
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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