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.

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.

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.

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.

Optimal Vibration Control of Membrane Structures with In-Plane Polyvinylidene Fluoride Actuators

2020 ◽  
Vol 20 (08) ◽  
pp. 2050095
Author(s):  
Yifan Lu ◽  
Qi Shao ◽  
Fei Yang ◽  
Honghao Yue ◽  
Rongqiang Liu
Keyword(s):  
Vibration Control ◽  
Polyvinylidene Fluoride ◽  
Vibration Suppression ◽  
Flexible Structures ◽  
Control Force ◽  
Membrane Structures ◽  
Optimization Criteria ◽  
High Flexibility ◽  
And Control ◽  
Actuator Placement

Different kinds of membrane structures have been proposed for future space exploration and earth observation. However, due to the low stiffness, high flexibility, and low damping properties, membrane structures are likely to generate large-amplitude (compared to the thickness) vibrations, which may lead to the degradation of their working performance. In this work, the governing equations are established at first, taking into account the modal control force induced by the polyvinylidene fluoride (PVDF) actuator. The optimal vibration control of the membrane structure is explored subsequently. A square PVDF actuator is attached on the membrane to achieve the vibration suppression. The influence of actuator position and control gains on the vibration control performance are studied. The optimal criteria for actuator placement and energy allocation are developed. Several case studies are numerically simulated to demonstrate the validity of the proposed optimization criteria. The analytical results in this study can serve as guidelines for optimal vibration control of membrane structures. Additionally, the proposed optimization criteria can be applied to active control of different flexible structures.

Response Control of Variable Stiffness Structure Using Electromagnetic Clutch

2003 ◽  
Vol 7 (2) ◽  
pp. 101-107
Author(s):  
Toshihiro Irie ◽  
◽  
Kiyoshi Shingu ◽  
Keita Kitamura ◽  
Yoshihiro Takagi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Vibration Control ◽  
Control Method ◽  
Variable Stiffness ◽  
Control Effect ◽  
Response Control ◽  
Electromagnetic Clutch

Vibration control method of a variable stiffness structure using an electromagnetic clutch is shown. The control effect is predicted by numerical simulation. On the basis of this result, an experiment is carried out using an actual apparatus to confirm the effect of the variable stiffness structure using the electromagnetic clutch.

Vibration Control and Unbalance Estimation of a Nonlinear Rotor System Using Disturbance Observer

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Jun Liu ◽  
Yukio Ishida ◽  
Yusuke Yoshimura
Keyword(s):  
Vibration Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Rotor System ◽  
Control Force ◽  
Rotor Systems ◽  
Parameter Variations ◽  
Speed Range ◽  
Disturbance Term ◽  
Nonlinear Rotor System

In rotating machinery, rotor unbalance causes many resonances at critical speeds corresponding to different modes. In this paper, a vibration control method for rotor systems utilizing disturbance observer is proposed. The nonlinear terms, unbalance, parameter variations, and uncertain terms of a rotor system are lumped into a disturbance term, and this term is canceled by using disturbance observer. As a result, the vibrations are suppressed to small amplitudes all over the rotational speed range. Simultaneously, unbalance of the first mode is estimated from the information of control force of disturbance observer. Moreover, the effects of parameter errors of the control system are also investigated. The validity of the proposed method is verified through numerical simulations and experiments.

An active vibration control model for coupled flexible systems

2008 ◽  
Vol 222 (11) ◽  
pp. 2087-2098
Author(s):  
J C Niu ◽  
A Y T Leung ◽  
C W Lim ◽  
P Q Ge
Keyword(s):  
Optimal Control ◽  
Vibration Control ◽  
State Space ◽  
Power Flow ◽  
Passive Control ◽  
Flexible Structures ◽  
Coupled System ◽  
The State ◽  
Coupled Systems ◽  
Control Force

This paper presents a novel general model for complex flexible coupled systems. In this model, parallel structures of force actuators and passive spring isolators are installed between the machine and the foundation, and some moment actuators such as piezoelectric patches are installed on the flexible foundation whose vibration cancellation feature is the key object of vibration control. This model combines active and passive control, force and moment control into a single unit to achieve the efficient vibration control of flexible structures by multiple approaches. The state-space governing equations of the coupled system are deduced. Based on the description of the state-space equation of the coupled system, the transmission paths for the power flow transmitted into the foundation are discussed in the frequency domain, and then combined into a single function. The function includes two parts: the passive and active terms, which can be conveniently employed in an optimal control strategy to achieve power flow control. The transmission characteristics of the power flow by optimal control are discussed in detail. Numerical simulations are presented to show that both force and moment controls in the analytical model can achieve substantial vibration cancellation.

The Response Analysis and Vibration Control of Flexible Arms With Two Nonlinear Factors

2021 ◽  
Vol 13 (01) ◽  
pp. 2150005
Author(s):  
Guoliang Ma ◽  
Minglong Xu ◽  
Liqun Chen
Keyword(s):  
Dynamic Response ◽  
Vibration Control ◽  
Control Method ◽  
Dead Zone ◽  
Response Analysis ◽  
Beam Model ◽  
Control Effect ◽  
Vibration Equation ◽  
The Dead ◽  
Flexible Arms

The space flexible arm has the characteristics of large flexibility and size, and external excitation will cause harmful vibration. In this paper, the dynamic response of flexible arms is analyzed, and the vibration control is studied when nonlinear factors are considered. First, the vibration equation is established according to the Hamilton’s principle, and the generalized force is derived by using rod model and beam model, respectively. Then the Runge–Kutta method is used to solve the vibration equation, and the dynamic response is obtained. Finally, the PD and fuzzy control simulations of three arms are established, and the dead zone and saturation nonlinearities are applied in the programs. The numerical results show that the external force causes significant response, and the vibration control method is effective. Besides, in order to achieve vibration control effect, it is necessary to reduce the dead zone nonlinear range.

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