• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.215-215
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• 2004

This paper describes a fault detection and fault handling algorithm to be used in a longitudinal vehicle cruise control systems. The fault diagnosis system consists of two structures to generate proper residuals and to find that which component has a fault. A systematic design of the fault diagnosis system using model-based techniques is presented. A linear observer is used to create a set of signals sensitive to faults in a radar sensor. The fault handling system consists of two structures to compensate for faults and degraded system performance. Simulation results show that the algorithm is effective for a fault diagnosis and handling in a longitudinal vehicle cruise control system.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.756-760
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• 2005

By development of a robot technology, personal robot is being developed very actively. Various infra-technologies are accumulated in hardware and software how by internal a lot of research and development efforts, and it is circumstance that actual commodity is announced. But, personal robot is applied to be acting near human, and takes charge of safety and connected directly a lot of works of home security, gas-leakage, fire-warning facilities, or/and etc. So personal robot must do safe and stable action even if any unexpected accidents are happened, important functions are always operated. In this paper, we are wished to show design structures for supporting fault-tolerant operation from our real-time robot middleware viewpoint. Personal robot, in being developed, was designed by module structure to do to interconnect and to interoperate among each module that is mutually implemented by each research facilities or company. Also, each modules can use appreciate network system that is fit for handling and communicating its data. To guarantee this, we have being developed a real-time network middleware, for especially personal robot. Recent our working is to add and to adjust some functions like connection management, distributed routing mechanism, remote object management, and making platform independent robot application execution environment with self-moving of robot application, for fault-tolerant personal robot.

• 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 the Korean Society of Industry Convergence
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• v.24 no.6_1
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• pp.659-667
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• 2021

This paper develops the theory for a novel fault-tolerant, permanent magnet biased, 4-active-pole, double plane, homopolar magnetic bearing. The Lagrange Multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrices for the failed bearing. If any of the 4 coils fail, the remaining three coil currents change via a novel distribution matrix such that the same opposing pole, C-core type, control fluxes as those of the un-failed bearing are produced. Magnetic flux coupling in the magnetic bearing core and the optimal current distribution helps to produce the same c-core fluxes as those of unfailed bearing even if one coil suddenly fails. Thus the magnetic forces and the load capacity of the bearing remain invariant throughout the failure event. It is shown that the control fluxes to each active pole planes are successfully isolated. A numerical example is provided to illustrate the new theory.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.928-934
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• 2002

A natural way to cope with fault tolerant control (FTC) problems is to modify the control parameters according to an online identification of the system parameters when a fault occurs. However. due to not only difficulties Inherent to the online multivariable identification in closed-loop systems, such as modeling errors, noise or the lack of excitation signals, but also long time requirement to identify the post-fault system and implemeutation of control problems during the identification process, we propose an alternative approach based on the observer-based fault detection and isolation (FDI) and model reference adaptive control (MRAC). The proposed robust fault diagnosis method is based on a bank of observers. We also propose a model reference adaptive control with changeable reference models according to the occurred faults. Simulation results of a flight control example show the validity and applicability of the proposed algorithms.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.5
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• pp.464-469
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• 2009

In this study, a new fault tolerant controller based on a model following adaptive technique is applied to the reconfiguration mode of supersonic advanced trainer. The designed controller is applied to the flight control system of high performance aircraft. To verify the performance of the proposed controller, numerical simulations are executed using a non-realtime nonlinear verification tool.

• Journal of Power Electronics
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• v.14 no.5
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• pp.946-956
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• 2014

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.61-68
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• 2007

In a naval combat system, the information processing node is a key functional equipment and performs major combat management functions including control sensor and weapon systems. Therefore, a failure of one of the node causes fatal impacts on overall combat system capability. There were many methodologies to enhance system availability by reducing the impact of system failure like a fault tolerant method. This paper proposes a fault tolerant mechanism for information processing node using a replication algorithm with hardware duplication. The mechanism is designed as a generic algorithm and does not require any special hardware. Therefore all applications in combat system can use this functionality. The asynchronous characteristic of this mechanism provides the capability to adapt this algorithm to the module which has low performance hardware.

• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.753-759
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• 2009

As many systems depend on electronics in an intelligent vehicle, concern for fault tolerance is growing rapidly. For example, a car with its braking controlled by electronics and no mechanical linkage from brake pedal to calipers of front tires(brake-by-wire system) should be fault tolerant because a failure can come without any warning and its effect is devastating. In general, fault tolerance is usually designed by placing redundant components that duplicate the functions of the original module. In this way a fault can be isolated, and safe operation is guaranteed by replacing the faulty module with its redundant and normal module within a predefined interval. In order to make in-vehicle network fault tolerant, this paper presents the concept and design methodology of an IEEE 1451 based dual CAN module. In addition, feasibility of the dual CAN network was evaluated by implementing the dual CAN module.