scholarly journals Active vibration control of flexible structures by means of a quasimodal control method

1988 ◽  
Vol 84 (S1) ◽  
pp. S48-S48
Author(s):  
Kenzo Nonami
1994 ◽  
Vol 6 (3) ◽  
pp. 243-248
Author(s):  
Katsuhiko Ezure ◽  
◽  
Kazuto Seto ◽  
Sinji Mitsuta ◽  
Katsumi Sawatari ◽  
...  

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.


Author(s):  
Fumio Doi ◽  
Kazuto Seto ◽  
Mingzhang Ren ◽  
Yuzi Gatate

Abstract In this paper we present an experimental investigation of active vibration control of a scaled bridge tower model under artificial wind excitation. The control scheme is designed on the basis of a reduced order model of the flexible structures using the LQ control theory, with a collocation of four laser displacement sensors and two hybrid electro-magnetic actuators. The experimental results in the wind tunnel show that both the bending and the twisting vibrations covering the first five modes of the structure are controlled well.


Author(s):  
Lawrence R. Corr ◽  
William W. Clark

Abstract This paper presents a numerical study in which active and hybrid vibration confinement is compared with a conventional active vibration control method. Vibration confinement is a vibration control technique that is based on reshaping structural modes to produce “quiet areas” in a structure as opposed to adding damping as in conventional active or passive methods. In this paper, active and hybrid confinement is achieved in a flexible beam with two pairs of piezoelectric actuators and sensors and with two vibration absorbers. For comparison purposes, active damping is achieved also with two pairs of piezoelectric actuators and sensors using direct velocity feedback. The results show that both approaches are effective in controlling vibrations in the targeted area of the beam, with direct velocity feedback being slightly more cost effective in terms of required power. When combined with passive confinement, however, each method is improved with a significant reduction in required power.


Author(s):  
Kazuto Seto ◽  
Yoshihiro Toba ◽  
Fumio Doi

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.


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