• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.17-22
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• 2007

Vibration isolation equipments are mostly required in precise measurement and manufacturing system. Among all the vibration isolation equipments, air-spring is the most widely used equipment because of low resonant frequency and high damping ratio. In this study, we used Takagi-Sugeno fuzzy method to design an active vibration isolation system using air-spring, and compared the fuzzy method with passive control method and PID control method. Due to the non-linearity characteristics of air-spring, fuzzy controller was verified to be the most effective both in simulation and experiment.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.184-189
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• 2006

In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by rising experiment and simulation. Optimal design for a passive air spring can be obtained by fluting the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the act ive vibration isolation table wi th the bet ter isolation performance.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.357-362
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• 2002

The underlying principle of fault detection via unknown input observer is to make the state estimation error independent of disturbances(or unknown inputs). In this paper, we present a systematic method that can exactly assign the eigenstructure with disturbance suppression and fault isolation capability. A desired eigenstructure for both fault isolation and disturbance suppression is obtained by an optimization method. For the dual purposes, terms for fault isolation and far disturbance suppression are included in the employed objective function for the optimization. The proposed scheme is applied to a simple example to confirm the usefulness of the method.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.221-229
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• 2001

The effect of Mo underlayer on the magnetic properties of CoCrTa/Cr films deposited on glass substrates were investigated. The coercivity increased and the coercivity squareness decreased by introducing Mo underlayer. The coercivity increase was attributed to the increase of in-plane c-axis orientation and magnetic isolation of Co grains deposited on Cr/Mo underlayer. The decrease of coercivity squarenesses seemed to be caused by the increase of magnetic isolation. The increase of magnetic isolation of Co grains was attributed to the diffusion of Mo atoms into grain boundaries of Co films and the physical isolation of Co grains. The coercivity of CoCrTa/Cr/Mo showed maximum values at Mo thickness of $400{\AA}$. The appearance of the maximum coercivity at that thickness was attributed to the development of strong $Co(10{\bar{1}}0)$ and $Co(10{\bar{1}}1)$ preferred orientation.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.292-297
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• 2000

The seismic isolation technology has appeared to be increasingly necessary for highway bridges, LNG tank, nuclear power plant, and building structures in view of earthquake vibrations. Also high-technology industries require effective seismic protection. The Seismic Isolation Bearing - High Damping Rubber Bearing - system has been counted as the most effective way fur seismic isolation, which is now under development and widely used in industries. Here, the commercial FEM software for nonlinear analysis, MARC, has provided force-displacement curves on the rubber system. The analyses have been carried out about fourteen cases; 25%, 50%, 75%, 100%, 125% and 150% horizontal displacements with a different frequency - 0.01Hz and 0.50Hz - and 100% horizontal displacement with four different frequency - 0.01Hz, 0.16667Hz, 0.3333Hz and 0.50Hz. The unknown constants of the strain energy function of Ogden model have been obtained by a tension test and planar shear test.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.140-148
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• 2000

This paper presents a fault detection and isolation(FDI) method based on Generalized Likelihood Ratio(GLR) test for the tightly coupled SDINS/CPS system. The GLR test is known to have the capability of detecting an assumed change while estimating its occurrence time and magnitude, and isolating the changing part. Once a fault is detected even if we don't know if the fault occurrs at either INS or GPS, multi-hypothesized GLR scheme performs the fault isolation between INS and GPS, and find which satellite malfunctions. However, in the INS faulty case, it turned out to fail to accomodate the fault isolation between accelerometer and gyroscope due to the coupling effects and a poor observability of the system. Hence, to isolate the INS fault, it needs to change the attitude of the vehicle resulting in enhancing the degree of observability.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.111-114
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• 2005

The isolation performance of the S-band single-pole single-throw (SPST) monolithic microwave integrated circuit (MMIC) switch with two different RF-interconnection approaches, microstrip and grounded coplanar waveguide (GCPW) lines, are investigated. On-to-off isolation is improved by 5.8 dB with the GCPW design compared with the microstrip design and additional improvement of 6.9dB is obtained with the coplanar wire-bond interconnection (CWBI) at 3.4 GHz. The measured insertion loss and third-order inter-modulation distortion (IMD3) are less than 2.43 dB over 2.5 CHz $\sim$ 4 GHz and greater than 64 dBc.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2393-2405
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• 2015

This paper considers a decentralized multiple faults detection and isolation (FDI) scheme for reconfigurable manipulators. Inspired by their modularization property, a global sliding mode (GSM) based stable adaptive fuzzy decentralized controller is investigated for the system in fault free, while for the system suffering from multiple faults (actuator fault and sensor fault), the decentralized sliding mode observer (DSMO) is employed to detect their occurrence. Hereafter, the time and location of faults can be determined by a fault isolation scheme via a bank of DSMOs. Finally, the effectiveness of the proposed schemes in controlling, detecting and isolating faults is illustrated by the simulations of two 3-DOF reconfigurable manipulators with different configurations successfully.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.1-8
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• 2014

When seismic isolation system is applied to high aspect-ratio (height/wide-ratio) steel structures, there are several problems to be taken into consideration. One is lifting up tensile force on the isolation bearing by overturning moment caused by earthquake. Another is securing building stiffness to produce seismic isolation effects. Under these conditions, this paper reports the structural design of high-rise research building in the campus of Tokyo Institute of Technology. With the stepping-up system for the corner bearings, the narrow sides of single span framework are designed to concentrate the dead load as counter-weight for the tensile reaction under earthquake. Also we adopted concrete in-filled steel column and Mega-Bracing system covering four layers on north & south framework to secure the horizontal stiffness of the building.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.329-334
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• 2001

Recently, the high precision technology can not be developed continuously if we don't have anti vibration technology. Vibration isolation technology using an air spring and laminated robber bearing is widely used because it has excellent vibration isolation characteristics. We developed high precision vibration table with two good element(air spring and LRB) for semiconductor factory. Air Spring is used for isolating the vertical vibration and LRB is used for isolating the horizontal Vibration. As a result, It has D-Class degree in BBR-Criteria. In this paper, we talk about orifice characteristics in the self-damped air spring and design flow of the laminated robber bearing. The orifice characteristics is delicate shade of length and diameter. When we do experimentation to find orifice characteristics, length is fixed and diameter is changed. The orifice diameter is the wider and the air spring stiffness is the softer.