• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.68.4-68
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• 2002

$\textbullet$ This report presents an implementation a set of reusable software components which use of fault-tolerance embedded controller for railway signalling systems. These components can be used in real-time applications without application reprogramming. $\textbullet$ This library runs under VxWorks operating system and is oriented on real-time embedded systems. The library includes fault detection, fault containment, checkpointing and recovery components. $\textbullet$ The library enables to support high-speed response to fault occurrence in application software. Garbage collector together with VxWorks Watchdog provides both dead tasks detection and useless resources removing to avoid an overflow. Control flow...

• Journal of Drive and Control
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• v.16 no.3
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• pp.23-32
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• 2019

This study proposed a fault tolerant control algorithm for electro-hydraulic brake systems where permanent magnet synchronous motor (PMSM) drive is adopted to boost the braking pressure. To cope with motor position sensor faults in the PMSM drive, a braking pressure controller based on an open-loop speed control method for the PMSM was proposed. The magnitude of the current vector was determined from the target braking pressure, and motor rotational speed was derived from the pressure control error to build up the braking pressure. The position offset of the pump piston resulting from a leak in the hydraulic system is also compensated for using the open-loop speed control by moving the piston backward until it is blocked at the end of stroke position. The performance and stability of the proposed controller were experimentally verified. According to the results, the control algorithm can be utilized as an effective means of degraded control for electro-hydraulic brake systems in the case that a motor position sensor fault occurs.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.11
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• pp.786-795
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• 1988

In this paper a boiler control system simulator is designed and inplemeted in order to evaluate performance of the Fault Tolerant Control System. It simulates a boiler control system of a thermal power plant containtng boiler process, peripheral units and analog controller. The simulator uses a low order linear model for boiler first order models for the peripheral unit. Specifically the model of the analog controller is modularized and transformed to digital form if order to be implemented using a micro-processor board. The experimental results show the usability of the developed simulator for the performance test of the FTCS.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.667-673
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• 2006

Programmable electronic interlocking system plays key role in railway operation and is closely related to railway accidents, in which the programmable electronic controller of interlocking system may become sources. Redundant digital controllers are adopted as the interlocking controllers to prevent the accidents from the controllers being out of order. The redundant digital controllers being fault tolerant are realized through dual or triplex controllers. In this paper, we calculated safety and availability of the redundant digital controllers using Markov models, demonstrated key part to determine the availability ana the safety.

• Journal of IKEEE
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• v.24 no.3
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• pp.727-734
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• 2020

Fault tolerant corrective control for asynchronous sequential machines (ASMs) with transient faults is discussed in this paper. The considered ASM is vulnerable to a kind of faults whose manifestation may arise during transient transitions of the ASM, leading to transient faults occurring in non-fundamental mode. To overcome adverse effects caused by these faults, we present a novel corrective control scheme that can detect and tolerate transient faults in non-fundamental mode. The existence condition and design algorithm for an appropriate fault tolerant controller is addressed in the framework of corrective control theory. The applicability of the proposed control methodology is demonstrated in the FPGA experiment.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.372-375
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• 1989

In this paper, a new FTCS with the ability to perform original control objective without considerable loss of control performance in the face of any fault is proposed. The FTCS is composed of two interacting units, Adaptive Controller Unit and Fault Detection/Classification, where ACU performs primary control objective with basic process information(I/O) and environmental information fed by FDU and where FDU detect and classify faults and make decision on remidial action by the use of information provided by ACU.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.59-70
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• 2022

In this paper, we proposed an active fault tolerant control (AFTC) method for the position control of a quadrotor with complete loss of effectiveness of one motor. We obtained the dynamics of a quadrotor using Lagrangian equation without small angle assumption. For detecting the fault on a motor, we designed a fault detection module, which consists of the fault detection and diagnosis (FDD) module and the fault detection and isolation (FDI) module. For the FDD module, we designed a nonlinear observer that observes the states of a quadrotor based on the obtained dynamics. Using the observed states of a quadrotor, we designed residual signals and set the appropriate threshold values of residual signals to detect the fault. Also, we designed an FDI module to identify the fault location using the designed additional conditions. To make a quadrotor track the desired path after detecting the fault of a motor, we designed a fault tolerant controller based on the multiple sliding surface control (MSSC) technique. Finally, through simulations, we verified the effectiveness of the proposed AFTC method for a quadrotor with complete loss of effectiveness of one motor.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.56-66
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• 2016

Robustness is essential for model based FDI (Fault Detection and Isolation) and it is inevitable to have modeling errors and sensor signal noises during the process of FDI. This study suggests an improved method by applying NARX (Nonlinear Auto Regressive eXogenous) model and Kalman estimator in order to cope with problems caused by linear model errors and sensor signal noises in the process of fault diagnoses. Fault decision is made by the probability of the trend of gradually accumulated errors applying Fuzzy logic, which are robust to instantaneous sensor signal noises. Reliability of fault diagnosis is verified under various fault simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.2
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• pp.98-106
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• 2013

This paper proposes fault tolerant control laws using sliding mode control and adaptation laws for a satellite with reaction wheel faults. Considering system parameter errors and faults uncertainties in the dynamics of satellite, the control laws were designed. It was assumed that only reaction wheel failures occurred as faults. The reaction wheel faults were reflected in the multiply form. Because the proposed control laws satisfy the Lyapunov stability theorem, the stability is guaranteed. Through computer simulation, it was assured that the proposed adaptive sliding mode controller has a better performance than the existing sliding mode controller under unstable angular rates.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.371-374
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• 2004

Induction motors are a critical component of many industrial processes and are frequently integrated in commercially available equipment. Safety, reliability, efficiency, and performance are some of the major concerns of induction motor applications. Preventive maintenance of induction motors has been a topic great interest to industry because of their wide range application of industry. Since the use of mechanical sensors, such as vibration probes, strain gauges, and accelerometers is often impractical, the motor current signature analysis (MACA) techniques have gained murk popularity as diagnostic tool. Fault tolerant control (FTC) strives to make the system stable and retain acceptable performance under the system faults. All present FTC method can be classified into two groups. The first group is based on fault detection and diagnostics (FDD). The second group is independent of FDD and includes methods such as integrity control, reliable stabilization and simultaneous stabilization. This paper presents the fundamental FDD-based FTC methods, which are capable of on-line detection and diagnose of the induction motors. Therefore, our group has developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. This paper presents its architecture. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module is checking stator current, voltage, temperatures, vibration and speed of the motor. The DSPs share information from each sensor or DSP through DPRAM with hardware implemented semaphore. And it communicates the motor status through field bus (CAN, RS485). From the designed system, we get primitive sensors data for the case of normal condition and two abnormal conditions of 3 phase induction motor control system is implemented. This paper is the first step to drive multi-motors with serial communication which can satisfy the real time operation using CAN protocol.