• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.267-272
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• 1999

In many fields of automation, increasingly high demands are being placed on the availability and fault tolerance of programmable logic controller(PLC). Particularly in fields where a plant shutdown would be extremely expensive. In such cases, only redundant systems can offer the standard of availability required. The redundant configurations contain more then would normally be necessary for the relevant function. Fault tolerant systems will normally continue to operate even if one or more faults cause parts of the control system to fail.

• Smart Structures and Systems
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• v.16 no.2
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• pp.329-345
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• 2015

As commonly known, sensor errors and faulty signals may potentially lead structures in vibration to catastrophic failures. This paper presents a new approach to deal with sensor errors/faults in vibration control of structures by using the Fault detection and isolation (FDI) technique. To demonstrate the effectiveness of the approach, a space truss structure with semi-active devices such as Magneto-Rheological (MR) damper is used as an example. To address the problem, a Linear Matrix Inequality (LMI) based fixed-order $H_{\infty}$ FDI filter is introduced and designed. Modeling errors are treated as uncertainties in the FDI filter design to verify the robustness of the proposed FDI filter. Furthermore, an innovative Fuzzy Fault Tolerant Controller (FFTC) has been developed for this space truss structure model to preserve the pre-specified performance in the presence of sensor errors or faults. Simulation results have demonstrated that the proposed FDI filter is capable of detecting and isolating sensor errors/faults and actuator faults e.g., accelerometers and MR dampers, and the proposed FFTC can maintain the structural vibration suppression in faulty conditions.

• International Journal of Control, Automation, and Systems
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• v.6 no.3
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• pp.327-338
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• 2008

A fault tolerant control system design technique has been proposed and analyzed for managing performance degradation in the presence of multiple faults in actuators. The method is based on a control structure with a model reference reconfigurable control design in an inner loop and command input adjustment in an outer loop. The reduced dynamic performance requirements in the presence of different actuator faults are accounted for through different performance reduced (degraded) reference models. The degraded steady-state performances are governed by the reduced levels of command input. The reconfigurable controller is designed on-line automatically in an explicit model reference control framework so that the dynamics of the closed-loop system follow that of the performance reduced reference model under each fault condition. The reduced command input level is determined to prevent potential actuator saturation. The proposed method has been evaluated and analyzed using an aircraft example against actuator faults subject to constraints on the magnitude and slew-rate of actuators.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.240-249
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• 2013

This paper discusses the maneuvering control algorithm based on all-wheel independent driving and steering control techniques for special purpose 6WD/WS vehicles. The maneuvering control algorithms considering superior dynamic characteristics of high power in-wheel motors and independent steering system are designed to perform driving, steering, vehicle stability, and fault tolerant control. The maneuvering controller applies sliding and optimal control theories considering optimal torque distribution and friction circle related to the vertical tire force. The fault tolerant control algorithm is applied to obtain the similar maneuverability to that of the non-faulty vehicle. The simulations using the Matlab/Simulink dynamics model and experiments using HIL simulator mounting the real controllers with the designed control algorithms prove the improved performances in terms of vehicle stability and maneuverability.

• Journal of the Korea Society for Simulation
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• v.10 no.4
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• pp.11-20
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• 2001

In the IMT-2000 networks, the model of micro/pico cell is suggested for transmission of multimedia service. Hence, the efficient method is required for processing of mobile calls in micro/pico cell. In the central urban area, mobile calls may be dynamically increased because of many mobile users. And microcel]/picocell size has small size, handover calls will be more increased. Therefore, many of mobile calls is occurred at a cell in the central urban area, so channel requests for these calls will be increased in the call. In this paper, we propose a scheme, FTC(Fault Tolerant Channel allocation) which is the channel management method for hard handover and new call in a mobile cell of central urban area. When available channels in the cell are consumed, the FTC investigates channel states of neighbor cells in the RNC(Radio Network Controller) or BSC (Base Station Center), and provide available channel for mobile call. The ]no scheme is analyzed and compared with existing channel management method by simulation.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.88-95
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• 2007

TCN(Train Communication Network) adopts the master/slave protocol to implement real-time communication. In this network, a fault on the master node, cased by either hardware or software failure, makes the entire communication impossible over TCN. To reduce fault detection and recovery time, this paper propose the contention based mastership transfer algorithm. Slave nodes detect the fault of master node and search next master node using the proposed algorithm. This paper also shows the implementation results of a SoC-based Fault-Tolerant MVB Controller(FT-MVBC) which includes the fault-detect-logic as well as the MVB network logic to verify this algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.120-126
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• 2013

This paper proposes a novel scheme of fault detection and self-recovery for space-borne dual ring counters subject to transient faults. The considered ring counter is equipped with hardware redundancy, but it has a limited output domain where direct access to the current state is unavailable. We employ the theory of corrective control to detect any transient fault occurring to the counter bits and to realize immediate self-recovery of the ring counter back to the normal state. The structure of the fault-tolerant controller is designed to be minimal regardless of the counter size. To validate the applicability, we implement the proposed system on a commercial FGPA board.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.6
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• pp.1-7
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• 2008

FlexRay is a new standard of network communication system which provides a high speed serial communication, time triggered bus and fault tolerant communication between electronic devices for future automotive applications. FlexRay communication controller (CC) is the core of the FlexRay protocol specification. In this paper, we first design the FlexRay CC protocol specification and function parts using SDL (Specification and Description Language). Then, the system is re-designed using Verilog HDL based on the SDL source. The FlexRay CC system was synthesized using Samsung $0.35\;{\mu}m$ technology. It is shown that the designed system can operate in the frequency range above 80 MHz. In addition, to show the validity of the designed FlexRay system the FlexRay system is combined with sound source localization system in Robot applications. The combined system is implemented using ALTERA Excalibur ARM EPXA4F672C3. It is shown that the implemented system operates successfully.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2376-2378
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• 2002

Redundant Programmable Logic Controllers are used in practice with the aim of achieving higher degree of availability or fault tolerance. In the paper a proposed Multiplex-PC is controled for fault tolerance design. In order to select a Different-Vender by a Supervisor computer, a Multiplex-PC is designed by TCP/IP internet protocol[1]. Because TCP/IP internet protocol can not connect to CPU. We use TCP/IP internet protocol to join CPU. We have to use TCP congestion control to select Different-Vender [4]. The reliability of the fault tolerant is measured with MTBF(Mean Time Between Failures)[3].

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.70-72
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• 1999

Actuator (chopper) and sensors failures resulting from electric shock and mechanical vibration generating by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension systems. Thus, this paper proposes the reliable output feedback controller for the electromagnetic levitation systems against actuator, air-gap sensor and acceleration sensor failures. The designed controller is an extend version of a novel design technique which has the design method of the output feedback controller using dynamic compensator. The benefits of this scheme are demonstrated through the experimental results for the proposed controller against chopper, air-gap sensor and acceleration sensor failures of electromagnetic levitation system.