• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.484-490
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• 2008

In this paper, an integrated fault section detection and isolation strategy is proposed based on the application of the Distribution Automation System(DAS) utilizing advanced IT and communication technologies. The Feeder Remote Terminal Unit(FRTU) has been widely used to collect data in the Korean distribution system. The achieved data is adopted in this method for detecting multiple fault types. Especially in the case of single phase-to-ground fault, the fault section is detected by comparison of the zero-sequence current phase angle. The test results have verified the effectiveness of the proposed method in a radial distribution system through extensive simulations in Matlab/Simulink. Furthermore, a communication-based demo system identical to the simulation model has been developed, and it can be applied as an online monitoring and control program for fault section detection and isolation.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.150-156
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• 2007

In this paper, we focus on the fault detection and isolation(FDI) method for inertial navigation system with three two-degree of freedom dynamically tuned gyros(DTG) on orthogonal sensor configuration. we propose the FDI method which can detect the fault of each DTGs rather than the fault of each sensing axis. The proposed FDI method is separated into two FDI modules according to the fault magnitude in order to improve the reliability of fault detection information. For large fault detection, only instantaneous DTG measurement is used to detect a fault DTG within a short time. For small fault detection, the integrated value of DTG measurements are used to detect a fault DTG. It takes a more time to detect a fault but it serves more reliable fault detection information. Using the proposed FDI method with consideration of DTG fault characteristic, we could find out a fault DTG successfully.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.922-927
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• 2002

A variable structure control (VSC) based model following control system that possesses fault detection and isolation (FDI) capability as well as fault tolerance property is proposed. The nonlinear part of the proposed control law. whose magnitude is determined by sliding variables, plays the role of suppressing fault effect. Thus, approximate fault reconstruction is also possible via the analysis of sliding variables. The proposed algorithm is applied to an active suspension system of pound vehicles to verify its applicability.

• International Journal of Control, Automation, and Systems
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• v.5 no.3
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• pp.329-336
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• 2007

This paper considers a fault accommodation problem for inertial navigation systems (INS) that have redundant inertial sensors such as gyroscopes and accelerometers. It is wellknown that the more sensors are used, the smaller the navigation error of INS is, which means that the error covariance of the position estimate becomes less. Thus, when it is decided that double faults occur in the inertial sensors due to fault detection and isolation (FDI), it is necessary to decide whether the faulty sensors should be excluded or not. A new accommodation rule for double faults is proposed based on the error covariance of triad-solution of redundant inertial sensors, which is related to the navigation accuracy of INS. The proposed accommodation rule provides decision rules to determine which sensors should be excluded among faulty sensors. Monte Carlo simulation is performed for dodecahedron configuration, in which case the proposed accommodation rule can be drawn in the decision space of the two-dimensional Cartesian coordinate system.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.32.3-32
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• 2002

We analyze the effect of main inertial sensor errors such as, misalignment, scale factor error and bias on the performance of modified sequential probability ratio test (SPRT) for sequential fault detection and isolation (FDI). The inertial sensor errors cause the modified SPRT method to give false alarm. We use a two-stage KF to obtain a modified parity vector with which the inertial sensor errors can be removed and thus modified SPRT method can be used regardless of inertial sensor errors.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.364-370
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• 2004

In this paper, we propose a FDI method, which comes from singular value decomposition of measurement matrix fur redundant sensors. We analyze the performance of the proposed FDI method by comparing with the GLT method in two ways such as FDI performance and GN＆C performance. Also, we propose a GN＆C performance index by combining FDI and GN＆C performance.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.256-263
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• 2002

Optical Multistage Interconnection Networks(OMINs) comprising photonic switches have been studied extensively as important interconnecting building blocks for communication networks and parallel computing systems. A basic element of photonic switching networks is a 2$\times$2 directional coupler with two inputs and two outputs. This paper is concerned with the diagnosis of cross-talk-faults in OMINs. As the size of today's network becomes very large, the conventional diagnosis methods based on tests and simulation have become inefficient, or even more, impractical. In this paper, we propose a simple and easily implementable algorithm for detection and isolation of the single crosstalk-fault in OMINs. Specifically, we develope an algorithm fur the isolation of the source fault in switching elements whenever the single crosstalk-fault is detected in OMINS. The proposed algorithm is illustrated by an example of 16$\times$16 banyan network.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.769-772
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• 1999

In this paper we propose an FDI(fault detection and isolation) algorithm to detect and isolate single faults in linear systems. When a change in the system occurs the errors between the system output and the estimated output cross a threshold, and once a fault in the system is detected, the FCFM statistically isolates the fault by using the error between each neural network based fault model output and the system output.

• Earthquakes and Structures
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• v.18 no.3
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• pp.349-365
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• 2020

Since the peak seismic response of a base-isolated building strongly depends on the characteristics of the imposed seismic ground motion, the behavior of a base-isolated building under different seismic ground motions is studied, in order to better assess their effects on its peak seismic response. Specifically, the behavior of a typical steel building is examined as base-isolated with elastomeric bearings, while the effect of near-fault ground motions is studied by imposing 7 pairs of near- and 7 pairs of far-fault seismic records, from the same 7 earthquake events, to the building, under 3 different loading combinations, through three-dimensional (3D) nonlinear dynamic analyses, conducted with SAP2000. The results indicate that near-fault seismic components are more likely to increase the building's peak seismic response than the corresponding far-fault components. Furthermore, the direction of the imposed earthquake excitations is also varied by rotating the imposed pairs of seismic records from 0◦ to 360◦, with respect to the major construction axes. It is observed that the peak seismic responses along the critical incident angles, which in general differ from the major horizontal construction axes of the building, are significantly higher. Moreover, the influence of 5% and 10% accidental mass eccentricities is also studied, revealing that when considering accidental mass eccentricities the peak relative displacements of the base isolated building at the isolation level are substantially increased, while the peak floor accelerations and interstory drifts of its superstructure are only slightly affected.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.57-64
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• 2005

In two-degree of freedom(TDOF) inertial sensors, two axes are mechanically correlated with each other. Fault source of one axis sensor may affect the other axis sensor, and therefore multiple fault detection and isolation(FDI) technique is required. Conventional FDI techniques using hardware redundancy need four TDOF inertial sensors for FDI. In this study, three TDOF inertial sensor redudancy case is considered, where conventional FDI technique can detect the fault, but cannot isolate the fault sensor. Hybrid FDI technique is proposed to solve this problem. Hybrid FDI technique utilizes the analytic redundancy by utilizing the unscented kalman filter as well as hardware redundancy for FDI. To verify the effectiveness of the proposed FDI technique, numerical simulations are performed using six degree of freedom nonlinear aircrft dynamics.