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

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.

Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda

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.


Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda

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.


Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda

A scheduling strategy of multiple semi-active control laws for various earthquake disturbances is proposed to maximize the control performance. Generally, the semi-active controller for a given structural system is designed as a single control law and the single control law is used for all the forthcoming earthquake disturbances. It means that the general semi-active control should be designed to achieve a certain degree of the control performance for all the assumed disturbances with various time and/or frequency characteristics. Such requirement on the performance robustness becomes a constraint to obtain the optimal control performance. We propose a scheduling strategy of multiple semi-active control laws. Each semi-active control law is designed to achieve the optimal performance for a single earthquake disturbance. Such optimal control laws are scheduled with the available data in the control system. As the scheduling mechanism of the multiple control laws, a command signal generator (CSG) is defined in the control system. An artificial neural network (ANN) is adopted as the CSG. The ANN-based CSG works as an interpolator of the multiple control laws. Design parameters in the CSG are optimized with the genetic algorithm (GA). Simulation study shows the effectiveness of the approach.


2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ahmad Paknejad ◽  
Guoying Zhao ◽  
Simon Chesné ◽  
Arnaud Deraemaeker ◽  
Christophe Collette

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.


Author(s):  
Kazuhiko Hiramoto ◽  
Taichi Matsuoka ◽  
Katsuaki Sunakoda

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.


2008 ◽  
Vol 56 ◽  
pp. 182-187
Author(s):  
Antonio Occhiuzzi

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.


2013 ◽  
Vol 798-799 ◽  
pp. 443-447
Author(s):  
Qi Chen LU ◽  
Hui Bin LI ◽  
Hua Huang

Studying on adaptive active noise control (AANC) system of the truck interior cab to reduce the low-frequency noise,a normalization FLMS algorithm simulink model is established in Matlab/Simulink.Then taking it as the core,a feedforward adaptive active control system and a feedback adaptive active control system of the tuck interior cab are established in Matlab/Simulink .Considerating the actual error channels effects on systems ,the noise reduction effects of two adaptive active control systems are verified from the simulintion results.Through comparing the two wo adaptive active control systems,we found that the feedforward adaptive active control system is more stable.


Author(s):  
Sadao Akishita ◽  
Kei Ameyama ◽  
Atsushi Mitani

This paper describes the active control systems for reducing floor impulse noise. The control system is comprised of actively controlled modular thin plates, which wholly cover the surface of concrete slab structure in the ceiling, and in each of which the mechanical vibration is controlled independently with bimorph type piezoelectric actuators. An active control system of modular plate is presented, where five actuators and five sensors are applied to control low frequency modes of bending vibration in the plate. The control system is now under development, main investigation items of whch are designing of vibration characteristics of modular thin plate, the active control system appropriate to the characteristics and cost reduction of the actuators and sensors.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ma Yong-Quan ◽  
Qiu Hong-Xing

The integrated multiobjective optimal design method for structural active control system is put forward based on improved Pareto multiobjective genetic algorithm, through which the position of actuator is synchronously optimized with active controller. External excitation is simulated by stationary filtered white noise. The root-mean-square (RMS) of structural response and active control force can be achieved by solving Lyapunov equation in the state space. The design of active controller adopts linear quadratic regulator (LQR) control algorithm. Minimum ratio of the maximum RMS of controlled structural displacement divided by the maximum RMS of uncontrolled structural displacement and minimum ratio of the maximum RMS of controlled structural shear divided by the maximum RMS of uncontrolled structural shear, together with minimization of the sum of RMS of active control force, are used as the three objective functions of multiobjective optimization. The optimization process takes the impact of structure and excitation parameter on the optimized results. An eight-storey six-span plane steel frame was used as an emulational example to demonstrate the validity of this optimization method. Results show that the proposed integrated multiobjective optimal design method is simple, efficient, and practical with good universality.


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