Vibration Control Method and Adaptability for Flexible Structures With Distributed Parameters Using a Hybrid Dynamic Absorber

1995 ◽  
Author(s):  
Kazuto Seto ◽  
Susumu Kondo ◽  
Katsuhiko Ezure
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Controller Design ◽  
Flexible Structures ◽  
Vibration Modes ◽  
Order Model ◽  
Reduced Order ◽  
Distributed Parameters ◽  
Dynamic Absorber ◽  
Lq Control

Abstract This paper examines the vibration control of a flexible structure using a hybrid dynamic absorber. A new method for modeling flexible structures with distributed parameters using a reduced-order model with lumped parameters is specified. Both prevention of spillover and physical correspondence at the modeling points are taken into consideration. Due to restrictions of controller design it is necessary to employ reduced-order models of flexible structures when using LQ control theory to control vibration. By ignoring higher mode orders model reduction may invite vibration instability called spillover. In order to prevent spillover nodes of higher-order vibration modes are selected as modeling points. The effectiveness of this method is demonstrated by applying vibration control to a flexible tower-like structure. In addition the robustness of the control system is tested by placing the sensors and absorbers at points different from those selected by the model.

Experimental Study on Arrangements of Setting Points of an Actuator and Sensor for the Vibration Control of Flexible Structures

1994 ◽  
Vol 6 (4) ◽  
pp. 292-297
Author(s):  
Kazuto Seto ◽  
◽  
Katsuhiko Ezure ◽  
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Vibration Mode ◽  
Controller Design ◽  
Flexible Structures ◽  
Reduced Order Model ◽  
Displacement Sensor ◽  
Order Model ◽  
Reduced Order ◽  
Dynamic Absorber

This paper proposes an experimental study on the arrangements between the setting points of an actuator and sensor for the vibration control of a flexible structure, when a vibration controller is mounted at an arbitrary position on the structure. The important vibration mode of the structure to be controlled is its first mode, because it is excited most sensitively by strong winds. It is therefore necessary to make a reduced-order model represented by a one-degree-of-freedom system at an arbitrary location, in consideration of preventing spillover instability. In this paper, non-observability is used for making the reduced-order model, and the LQ control theory is used for controller design. For controlling vibration, a reduced-order model is constructed at the setting point of a hybrid dynamic absorber, and a displacement sensor is set at the vibration node of the second vibration mode. Then, the setting point of the sensor is changed to compare control effects by means of this model. It is demonstrated experimentally that a hybrid dynamic absorber, designed by this method, is capable of controlling vibration well without causing spillover instability. In addition, it is considered that the setting point of the sensor influences the robustness of the control system.

Solving Vibration Control Problems Using Reduced Order Models for Flexible Structures: A Genetic Algorithm Approach

1997 ◽  
Author(s):  
Sourav Kundu ◽  
Kentaro Kamagata ◽  
Shigeru Sugino ◽  
Takeshi Minowa ◽  
Kazuto Seto
Keyword(s):  
Genetic Algorithm ◽  
Vibration Control ◽  
Controller Design ◽  
Fitness Function ◽  
Flexible Structures ◽  
Design Solution ◽  
Reduced Order Models ◽  
Reduced Order ◽  
Fitness Value ◽  
Genetic Algorithm Approach

Abstract A Genetic Algorithm (GA) based approach for solution of optimal control design of flexible structures is presented in this paper. The method for modeling flexible structures with distributed parameters as reduced-order models with lumped parameters, which has been developed previously, is employed. Due to some restrictions on controller design it is necessary to make a reduced-order model of the structure. Once the model is established the design of flexible structures is considered as a feedback search procedure where a new solution is assigned some fitness value for the GA and the algorithm iterates till some satisfactory design solution is achieved. We propose a pole assignment method to determine the evaluation (fitness) function to be used by the GA to find optimal damping ratios in passive elements. This paper demonstrates the first results of a genetic algorithm approach to solution of the vibration control problem for practical control applications to flexible tower-like structures.

Motion and Vibration Control of a Flexible Transportation System

2003 ◽  
Author(s):  
Keisuke Takemoto ◽  
Masato Mori ◽  
Toru Watanabe ◽  
Kazuto Seto
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Transportation System ◽  
Modeling Method ◽  
Vibration Modes ◽  
Simulation Experiments ◽  
Reduced Order ◽  
Control Effectiveness ◽  
Modeling Approach ◽  
And Control

This paper shows a lumped modeling approach and a motion and vibration control method for a transportation system. The modeling approach is made on the premise that motion influences vibration, but that vibration doesn’t influence motion. To obtain well suppressed vibration and a robustness for the system, LQI control is adopted. It is shown that this theory has superior robustness for in motion and vibration control with variations of the parameters [1]. The control effectiveness is demonstrated through simulation experiments. The vibration modes that occur accordingly become flexible might cause a spillover instability problem. Thus, the purpose of the research is to control such vibration and motion using the modeling method presented by Seto, called the “reduced order physical modeling method” [2]. Computer simulation and control experiments are carried out and the effectiveness of the procedures presented is investigated.

Vibration and Motion Control of Flexible Structures by Hybrid Dynamic Absorber(Influence of Vibration System with Nonlinear Element)

1994 ◽  
Vol 6 (3) ◽  
pp. 230-236
Author(s):  
Shinji Mitsuta ◽  
◽  
Kazuto Seto ◽  
Hiroyuki Ito ◽  
Akio Nagamatsu ◽  
...  
Keyword(s):  
Vibration Control ◽  
Motion Control ◽  
Control Method ◽  
Flexible Structures ◽  
Sine Wave ◽  
Flexible Structure ◽  
Control Force ◽  
Control Effect ◽  
Dynamic Absorber ◽  
Servo Controller

Recently, the necessity for making machines weighing less and operating at high speeds has increased. This paper is concerned with vibration and motion control by a control system which combines a servo controller and a hybrid dynamic absorber. In our method, vibration control and motion control are designed independently. First, the dynamics of a tower structure and a servo motor are modeled. Then, it is shown experimentally that although vibration control by the servo controller alone causes instability due to nonlinear elements such as friction or rattle, the hybrid dynamic absorber does not easily cause this sort of instability. On the comparison of vibration control effect and control force, the hybrid dynamic absorber requires less force. Finally, to know the effect of the new method, we evaluated the motions (triangular wave and sine wave) of the flexible structure. The effectiveness of this vibration and motion control method for the flexible structure was demonstrated by simulations and experiments.

Motion and Vibration Control of a Flexible Transportation System Used Piezoelectric Films as Sensor for Vibration Detection

2005 ◽  
Author(s):  
Masato Nishikiori ◽  
Toru Watanabe ◽  
Kazuto Seto
Keyword(s):  
Vibration Control ◽  
Flexible Structures ◽  
Transportation System ◽  
Settling Time ◽  
Long Distance ◽  
Reduced Order ◽  
Control Approach ◽  
Modes Of Vibration ◽  
Piezoelectric Films ◽  
Lq Control

This paper deals with motion and multi-modes of vibration control of a flexible transportation system. In order to reduce a settling time from one position to another one, the vibration control is remarkably important on the transportation system. Since transportation system moves long distance, no limit in the measuring range of the sensor is required. For the purpose, piezoelectric films pasted on flexible structures are used as the point sensor to detect vibrations. To control the first two vibration modes, the reduced-order physical modeling method proposed by authors is applied and the control system is designed by LQ control approach. Control experiments demonstrate that the settling time is well shortening by controlling many-modes of vibration in addition to motion.

Active Vibration Control of Flexible Structures Arranged in Parallel

1994 ◽  
Vol 6 (3) ◽  
pp. 243-248
Author(s):  
Katsuhiko Ezure ◽  
◽  
Kazuto Seto ◽  
Sinji Mitsuta ◽  
Katsumi Sawatari ◽  
...  
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Low Frequency ◽  
Tall Buildings ◽  
Control Force ◽  
Active Vibration ◽  
Strong Winds ◽  
Lq Control

This paper proposes a vibration control method for flexible structures arranged in parallel. In recent years, tall buildings equipped with active dynamic absorbers have been popularized to maintain living comfort by reducing the vibration of higher floors by strong winds. The higher a tall building the lower its natural frequency. It will be difficult to control the vibration of ultra-tall buildings using active dynamic absorbers because of difficulties in obtaining enough control force under the lower frequency. According to the proposed method, a pair of flexible buildings are controlled actively by controlling each other by means of actuators placed between them. Therefore, it is able to obtain enough control force under the low frequency. In this paper, a reduced-order model expressed by 2DOF systems is proposed for preventing spillover instability. The LQ control theory is applied to the design of the control system. The effectiveness of this method is demonstrated theoretically as well as experimentally.

Robust vibration control of flexible panel: modeling and simulation

2017 ◽  
Vol 14 (5) ◽  
pp. 433-442
Author(s):  
Aalya Banu ◽  
Asan G.A. Muthalif
Keyword(s):  
Robust Control ◽  
Vibration Control ◽  
Controller Design ◽  
Control Strategies ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Parametric Uncertainty ◽  
Design Algorithm ◽  
Content Type ◽  
And Performance

Purpose This paper aims to develop a robust controller to control vibration of a thin plate attached with two piezoelectric patches in the presence of uncertainties in the mass of the plate. The main goal of this study is to tackle dynamic perturbation that could lead to modelling error in flexible structures. The controller is designed to suppress first and second modal vibrations. Design/methodology/approach Out of various robust control strategies, μ-synthesis controller design algorithm has been used for active vibration control of a simply supported thin place excited and actuated using two piezoelectric patches. Parametric uncertainty in the system is taken into account so that the robust system will be achieved by maximizing the complex stability radius of the closed-loop system. Effectiveness of the designed controller is validated through robust stability and performance analysis. Findings Results obtained from numerical simulation indicate that implementation of the designed controller can effectively suppress the vibration of the system at the first and second modal frequencies by 98.5 and 88.4 per cent, respectively, despite the presence of structural uncertainties. The designed controller has also shown satisfactory results in terms of robustness and performance. Originality/value Although vibration control in designing any structural system has been an active topic for decades, Ordinary fixed controllers designed based on nominal parameters do not take into account the uncertainties present in and around the system and hence lose their effectiveness when subjected to uncertainties. This paper fulfills an identified need to design a robust control system that accommodates uncertainties.

Active Vibration Control of a Triple Flexible Structures Combined With Actuators

1995 ◽  
Author(s):  
Kazuto Seto ◽  
Yoshihiro Toba ◽  
Fumio Doi
Keyword(s):  
Vibration Control ◽  
Large Scale ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Low Frequency ◽  
Tall Buildings ◽  
Control Force ◽  
Active Vibration ◽  
Strong Winds ◽  
Lq Control

Abstract In order to realize living comfort of tall buildings by reducing the vibration of higher floors by strong winds, this paper proposes a new method of vibration control for flexible structures with a large scale. The higher a tall building the lower its natural frequency. Since obtaining sufficient force to control the lower frequency vibrations of tall buildings is a difficult task, controlling the vibration of ultra-tall buildings using active dynamic absorbers is nearly impossible. This problem can be overcome by placing actuators between a pair of two or three ultra-tall buildings and using the vibrational force of each building to offset the vibrational movement of its paired mate. Therefore, it is able to obtain enough control force under the low frequency when the proposed method is used. In this paper, a reduced-order model expressed by 2DOF system under taking into consideration for preventing spillover instability is applied to control each flexible structure. The LQ control theory is applied to the design of such a control system. The effectiveness of this method is demonstrated theoretically as well as experimentally.

The Method of Successive Decrease and the Concept of Harmonic Wave Filter in Structural Wave Control

1995 ◽  
Author(s):  
Dajun Wang ◽  
Quan Wang ◽  
A. Y. T. Leung
Keyword(s):  
Vibration Control ◽  
Structural Control ◽  
Natural Frequencies ◽  
Control Method ◽  
Harmonic Wave ◽  
Flexible Structures ◽  
Modal Control ◽  
Large Space ◽  
Wave Filter ◽  
Wave Control

Abstract Most of the available vibration control methods for flexible structures are based on the modal control method, which, however, sometimes meets with problems. For examples, the problem of spillover has not been solved adequately. And, for flexible large space structures with closely spaced natural frequencies, it is very difficult to use modal method to treat vibration control problems because the modes corresponding to closely spaced and repeated frequencies can not be computed accurately. In recent years, the method of structural wave control has been developed, but it has not been studied sufficiently. The object of this paper is an attempt to solve some of the existing problems raised due to the application of the modal control method. A wave control method — the method of successive decrease is set up at first, which is aimed at one harmonic wave. Then, a new design method in wave control is proposed, based on the above method. The problem of control spillover is analyzed and the concept of harmonic wave filter is introduced. As an example, the problem of the control of structures with closely spaced natural frequencies is treated by both the method of modal control and the method of successive decrease. The numerical results show that the method of successive decrease is more effective than the method of modal control. It proves that the method of successive decrease and the concept of harmonic wave filter is promising in solving the problems of structural control.

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