• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.7
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• pp.557-564
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• 2002

To reduce unwanted vibrations in war ship which may be transmitted through underwater path, it is required to use high damping mounts to isolate the vibration. In this work, the beam structure with squeeze mode ER mount is proposed and response characteristics such as acceleration and force transmissibility of beam with constant voltage and optimal controller are experimentally analyzed. The controller is empirically realized and control responses are evaluates in frequency domains. Experiments show vibration reduction capability of squeeze mode ER mount.

• Magazine of korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.24-35
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• 2012

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.79-83
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• 2000

A sliding mode fuzzy control (SMFC) with disturbance estimator is applied to design a controller for the third generation benchmark problem on an wind-excited building. A distinctive feature in vibration control of large civil infrastructure is the existence of large disturbances, such as wind, earthquake, and sea wave forces. Those disturbances govern the behavior of the structure, however, they cannot be precisely measured, especially for the case of wind-induced vibration control. Since the structural accelerations are measured only at a limited number of locations without the measurement of the wind forces, the structure of the conventional control may have the feed-back loop only. General structure of the SMFC is composed of a compensation part and a convergent part. The compensation part prevents the system diverge, and the convergent part makes the system converge to the sliding surface. The compensation part uses not only the structural response measurement but also the disturbance measurement, so the SMFC has a feed-back loop and a feed-forward loop. To realize the virtual feed-forward loop for the wind-induced vibration control, disturbance estimation filter is introduced. the structure of the filter is constructed based on an auto regressive model for the stochastic wind force. This filter estimates the wind force at each time instance based on the measured structural responses and the stochastic information of the wind force. For the verification of the proposed algorithm, a numerical simulation is carried out on the benchmark problem of a wind-excited building. The results indicate that the present control algorithm is very efficient for reducing the wind-induced vibration and that the performance indices improve as the filter for wind force estimation is employed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.93-99
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• 1998

Mathematical model can be obtained by physical law or engineering theory. However it is always incomplete expression of the real system. In active controls to suppress vibration due to earthquake or wind load, modeling errors can often cause the problems of instability and performance degradation. In this paper, robust optimal controller design method using H$\infty$ control theory is developed for the systems which have uncertain natural frequency and design constraints. Numerical results show that the proposed H$\infty$ controller can avoid the performance degradation due to several errors and has better performance than conventional LQR method.

• Explosives and Blasting
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• v.22 no.1
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• pp.75-80
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• 2004

최근 도심지의 가속화에 따라 시가지 인근에서의 암반굴착이 활성화되고 있으며, 특히 보안을 요하는 구조물에 근접한 발과 또는 가동중의 설비 가까이 에서 발파굴착을 실시해야하는 등 주변환경을 충분히 고려하여 진동, 소음 및 비산을 효과적으로 제어할 수 있는 발파기술이 요구되고 있다. 이와 같은 배경에서 미진동 발파굴착을 위하여 콘크리트 파쇄기, 팽창성 파쇄제 등이 개발되어 실용화되고 있다. 국내에서는 (주)한화가 콘크리트 파쇄기(Finecker)를 개발하여 공급해 왔으며, (주)고려 노벨 화약에서는 저폭속(2,000 m/s) 화약을 2중의 Air Gap을 이용하여 진동 및 소음 제어하는 미진동 발파용 화약(Kinecker)을 출시하여 공급하고 있다. 이에 Kinecker의 원리와 특징 그리고 현장적용 사례 및 발파패턴을 소개하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1341-1344
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• 2007

최근에 노트북 컴퓨터의 가격 하락과 더불어 보급이 급속도로 확산되고 있다. 노트북 컴퓨터 간의 경쟁에서 얼마나 더 얇고 가볍게 만들 수 있는가는 가치 차별화의 근간이 된다. 따라서 노트북 컴퓨터의 박형화에서 HDD 나 ODD 같은 핵심 주변장치의 박형화는 핵심 이슈이다. 본 논문에서는 기존 노트북용 박형 광저장장치의 엑추에이터 개발에 있어서 보다 안정적인 제어가 될 수 있는 구조를 소개하고 엑추에이터의 실제 데이터를 이용하여 서보 제어에 있어서의 설계마진을 고찰해 보고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.127-132
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• 2007

In this paper, to overcome local damages of structures, an uncertainty of structural model, installing sensors of structures, and economics of building system, decentralized semi-active magnetorheological(MR) damper using the displacement or velocity transferred to the response of floor installed damper is proposed. Relative magnitude between the control force of dampers and the story shear force is difined as design variables and the performance indices response spectra analysis through nonlinear time history analysis excited by seismic loads is performed according to this design variables. And the performance of this decentralized MR damper is compared with previous centralized LQR control algorithm using 3-stories benchmark building structure excited by El Centro (1940, N.S) in order to evaluate the application of building structures.

• Journal of KSNVE
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• v.11 no.1
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• pp.68-75
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• 2001

A method for actively controlling dynamic reaction forces in flexible structures subject to persistent excitations is presented. Since reaction forces are not directly measured in flexible structures, reaction forces are estimated by using the Kalman filter. The estimated reaction force is used as an error signal in the adaptive feedforward disturbance cancellation controller. In order to compensate the static effect of the truncated modes in the reaction forces, the residual flexibility matrix is used with the Kalman filter. The paper presents the formulation of the reaction forces in conjunction with the Kalman filter estimator and the adaptive feedforward controller. The results show that the dynamic reaction forces at its supports in a flexible beam test rir are well suppressed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.198-203
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• 2002

A fuzzy logic controller design technique is proposed to apply for the control of flexible system under irregular disturbance. The fuzzy rules of $\ulcorner$Mode Selecting Fuzzy Controller$\lrcorner$ are constructed using displacement, velocity information and modal characteristics of the system. The frequency information of flexible system is picked up from $\ulcorner$Mode Selecting Unit$\lrcorner$ based on Fast-Fourier transform algorithm. Experiment is conducted to verify the proposed theoretical approach, Piezo ceramic and laser accelerometer are used as actuator and sensor in the experiments respectively

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.326.1-326
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• 2002

A fuzzy logic controller design technique is proposed to apply to the control of flexible system under irregular disturbance. The fuzzy rules of $\ulcorner$Mode Selecting Fuzzy Controller$\lrcorner$ are constructed using displacement, velocity information and modal characteristics of the system. The frequency information of flexible system is picked up from $\ulcorner$Mode Selecting Unit$\lrcorner$ based on Fast-Fourier transform algorithm. Experiment is conducted to verify the proposed theoretical approach. (omitted)