• Title/Summary/Keyword: Hardware redundancy

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Failure recoverability by exploiting kinematic redundancy

  • Park, Jonghoon;Chung, Wan-Kyun;Youm, Youngil
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.77-82
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    • 1996
  • This paper is concerned with how to utilize kinematic redundancy to reconstruct the inverse kinematic solution which is not attainable due to hardware limitations. By analyzing the error due to hardware limitations, we are to show that the recoverability of limitation reduces to the solvability of a reconstruction equation under the feasibility condition. It will be next shown that the reconstruction equation is solvable if the configuration is not a joint-limit singularity. The reconstruction method will be proposed based on the geometrical analysis of recoverability of hardware limitations. The method has the feature that no task motion error is induced by the hardware limitations while minimizing a possible null motion error, under the recoverability assumed.

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Hardware and Software Dependability Analysis of Embedded AVTMR(All Voting Triple Modular Redundancy) System (내장형 AVTMR 시스템의 하드웨어 및 소프트웨어 신뢰성 분석)

  • Kim, Hyun-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.7B
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    • pp.744-750
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    • 2009
  • In this paper, the unified Markov modeling of hardware and software for AVTMR(AlI Voting Triple Modular Redundancy) system is proposed and the dependability is analyzed. In hardware case, a failure rate is fixed to no time varying parameter. But, in software case, failure rate is applied with time varying parameter. Especially, the dependability(Reliability, Availability, Maintainability, Safety) of software is analyzed with G-O/NHPP for Markov modeling. The dependability of single and AVTMR system is analyzed and simulated with a unified Markov modeling method, and the characteristic of each system is compared accroding to failure rate. This kind of fault tolerat system can be applied to an airplane and life critical system to meet the requirement for a specific requirement.

A Study On The Reliability Characteristics of Fail-Safe Control Logic (고장-안전 제어논리의 신뢰성 특성에 관한 연구)

  • 한상섭;김민수;이정석;이기서
    • Journal of Applied Reliability
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    • v.1 no.1
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    • pp.9-15
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    • 2001
  • This paper modelled the fail-safe control logic through the frequency coding input and designed the 3-out of-6 self checker using the error detect coding method of information redundancy. In addition, this paper also peformed the reliability parallel numeric analysis regarding single module between fail-safe. control logic module and TMR(Triple Modular Redundancy), therefore, we achieved the result that the fail-safe control logic increases a functional reliability because of decreasing system waste cost and functional overhead rather than the existing hardware redundancy method.

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Communication Redundancy for Reliability Improvement in an Industrial Monitoring and Control System

  • Rhyu, Keel-Soo;Chung, Kyung-Yul
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.8
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    • pp.1291-1298
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    • 2004
  • In development of monitoring and control systems, one of the most important points is to consider a redundancy so that the system can be operated normally although hardware faults are partly occurred. The purpose of this paper is to introduce a monitoring and control system with a redundancy function for I/O servers and communication networks. I/O servers composed with an active server and a standby server. Each server also has 3 communication ports, 2 ports of them were connected to field units and the other 1 port was connected to the other server. Field units have to be constructed to 2 communication ports connected I/O servers through communication lines. Also, server communication module was implemented for analyzing and handling fault elements. and was submodularized for linking easily with a monitoring and control module. An experiment with 2 servers and 2 field units was constructed to demonstrate its effectiveness.

Analysis on the Reliability of the Multi-Module Hardware Redundancy in the Fault Tolerant System (고장포용시스템에서의 다중 모듈 하드웨어 여분의 신뢰도 분석)

  • Hong, Tae-Hwa;Kim, Hag-Bae
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.791-793
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    • 1999
  • 제어 컴퓨터의 고장으로 인해 인명이나 재산에 치명적 영향을 미치는 safety-critical 실시간 시스템을 제어하고 모니터링하기 위해 디지털 컴퓨터의 사용은 점점 일반화되고 있다. 특히, VLSI 기술의 급격한 발달로 인해 하드웨어가 초소형화 되고 대량생산이 가능해진 현실에서 이러한 제어 컴퓨터의 극대화된 신뢰도 요구를 만족시키기 위해 막중한 하드웨어 여분(hardware redundancy)이 널리 사용되고 있는 실정이다. 본 논문에서는 N개의 다중 모듈(multi-module)로 이루어진 하드웨어 여분의 운영 모드를 분석하고 각 운영 모드에서 고장이 발생할 경우 모드의 전환과 그로 인한 신뢰도의 변화를 계산할 것이다. 그리고 간단한 시뮬레이션을 통해 전환된 여러 모드 중 가장 우수한 신뢰도를 갖는 모드를 평가하게 된다.

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Switching Frequency Reduction Method for Modular Multi-level Converter utilizing Redundancy Sub-module (예비 서브모듈을 활용한 모듈형 멀티레벨 컨버터의 스위칭 주파수 저감 기법)

  • yoo, Seung-Hwan;Jeong, Jong-Kyou;Han, Byung-Moon
    • Proceedings of the KIPE Conference
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    • 2014.11a
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    • pp.11-12
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    • 2014
  • This paper introduces a scaled hardware model for the 10kVA, 1kV, 11-level MMC (Modular Multilevel Converter), which was manufactured in the lab based on computer simulations with PSCAD/EMTDC. Various experiments were conducted to verify the major operation algorithms of MMC. The hardware scaled-model developed in the lab can be utilized for analyzing the operation analysis and performance evaluation of MMC according to the modulation pattern and redundancy operation scheme.

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FDI considering Two Faults of Inertial Sensors (관성센서의 이중 고장을 고려한 고장 검출 및 분리)

  • 김광훈;박찬국;이장규
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.1
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    • pp.1-9
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    • 2004
  • Inertial navigation system with hardware redundancy must use FDI(Fault Detection and Isolation) method to remove the influence of faulty sensors. Until now, several FDI methods such as PSA(Parity Space Approach), GLT(Generalized Likelihood ratio Test) and OPT(Optimal Parity vector Test) method are generally used. However, because these FDI methods only consider the situation that the system has one faulty sensor, these methods cannot be directly adapted for the system with two faulty sensors. To solve this problem, in this paper, PSA method is analyzed and based on this result, new FDI method called EPSA is proposed to consider a detection and an isolation of two faulty sensors in inertial navigation system.

A Study on the Design and Evaluation of Dual-Duplex System (듀얼 듀플렉스 시스템 설계 및 평가에 관한 연구)

  • Kim, Hyun-Ki;Shin, Duck-Ho;Lee, Key-Seo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.50 no.4
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    • pp.168-176
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    • 2001
  • In this paper, we develop a dual-duplex system which detects a fault by hardware comparator and switches to hot standby redundancy. This system is designed on the basis of MC68000 and can be used in VMEbus. To improve reliability, the dual-duplex system is designed in dual modular redundancy. The failure rate of electrical element is calculated in MILSPEC-217F, and the system RAMS(Reliability, Availiability, Maintainability and Safety) and MTTF(Mean Time to Failure) are evaluated by Markov modeling method. As the evaluation result shows improved reliability, it can be used as a component hardware for a highly reliable control system.

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Hybrid Fault Detection and Isolation Method for Inertial Sensors Using Unscented Kalman Filter (Unscented 칼만필터를 이용한 관성센서 복합 고장검출기법)

  • Park, Sang-Kyun;Kim, You-Dan;Park, Chan-Guk;Roh, Woong-Rae
    • 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.

Hardware-Saving Realizations of Interpolators and Decimators Using Periodically Time-Varying Coefficients

  • Ratansanya, San;Amornraksa, Thumrongrat;Tipakorn, Bundit
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.860-863
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    • 2002
  • Realizations of multirate converters are proposed using periodically time-varying (PTV) structures. By exploiting the computational redundancy of the filtering operation in a multirate filter, it is possible to implement the filter with much less hardware. In the proposed implementations, several coefficients time-share in a periodic fashion the hardware of one multiply-and-add. Therefore, each multiply-and-add circuit performs different coefficient scalings at different time instants within a period. Compared to the direct form realization, the proposed realizations reduce the hardware of an interpolator and a decimator by a factor of approximately U and M, respectively, while retaining the same processing speed, where U and M are the upsampling and downsampling factors, respectively. The approach can be used to obtain realizations for sampling rate conversion by a rational factor of U/M, where U and M are relatively prime, in which case hardware reduction by a factor of approximately UM can be achieved.

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