• Title/Summary/Keyword: Two faults

검색결과 504건 처리시간 0.032초

Multiple Faults Detection and Isolation via Decentralized Sliding Mode Observer for Reconfigurable Manipulator

  • Zhao, Bo;Li, Chenghao;Ma, Tianhao;Li, Yuanchun
    • Journal of Electrical Engineering and Technology
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    • 제10권6호
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    • pp.2393-2405
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    • 2015
  • This paper considers a decentralized multiple faults detection and isolation (FDI) scheme for reconfigurable manipulators. Inspired by their modularization property, a global sliding mode (GSM) based stable adaptive fuzzy decentralized controller is investigated for the system in fault free, while for the system suffering from multiple faults (actuator fault and sensor fault), the decentralized sliding mode observer (DSMO) is employed to detect their occurrence. Hereafter, the time and location of faults can be determined by a fault isolation scheme via a bank of DSMOs. Finally, the effectiveness of the proposed schemes in controlling, detecting and isolating faults is illustrated by the simulations of two 3-DOF reconfigurable manipulators with different configurations successfully.

광 버스트 스위칭을 위한 광 교환기에서의 다중 누화고장 진단기법 (Diagnosis of Multiple Crosstalk-Faults in Optical Cross Connects for Optical Burst Switching)

  • 김영재;조광현
    • 제어로봇시스템학회논문지
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    • 제9권3호
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    • pp.251-258
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    • 2003
  • Optical Switching Matrix (OSM) or Optical Multistage Interconnection Networks (OMINs) comprising photonic switches have been studied extensively as important interconnecting blocks for Optical Cross Connects (OXC) based on Optical Burst Switching (OBS). A basic element of photonic switching networks is a 2$\times$2 directional coupler with two inputs and two outputs. This paper is concerned with the diagnosis of multiple crosstalk-faults in OSM. As the network size becomes larger in these days, the conventional diagnosis methods based on tests and simulation become inefficient, or even more impractical. We propose a simple and easily implementable algorithm for detection and isolation of the multiple crosstalk-faults in OSM. Specifically. we develop an algorithm for isolation of the source fault in switching elements whenever the multiple crosstalk-faults arc detected in OSM. The proposed algorithm is illustrated by an example of 16$\times$16 OSM.

Fault Detection in Automatic Identification System Data for Vessel Location Tracking

  • Da Bin Jeong;Hyun-Taek Choi;Nak Yong Ko
    • Journal of Positioning, Navigation, and Timing
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    • 제12권3호
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    • pp.257-269
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    • 2023
  • This paper presents a method for detecting faults in data obtained from the Automatic Identification System (AIS) of surface vessels. The data include latitude, longitude, Speed Over Ground (SOG), and Course Over Ground (COG). We derive two methods that utilize two models: a constant state model and a derivative augmented model. The constant state model incorporates noise variables to account for state changes, while the derivative augmented model employs explicit variables such as first or second derivatives, to model dynamic changes in state. Generally, the derivative augmented model detects faults more promptly than the constant state model, although it is vulnerable to potentially overlooking faults. The effectiveness of this method is validated using AIS data collected at a harbor. The results demonstrate that the proposed approach can automatically detect faults in AIS data, thus offering partial assistance for enhancing navigation safety.

Fault Detection in the Two-for-One Twister

  • Park, Ho-Cheol;Koo, Doe-Gyoon;Lee, Jie-Tae;Cho, Hyun-Ju;Han, Young-A;Sohn, Sung-Ok;Ji, Byung-Chul
    • International Journal of Control, Automation, and Systems
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    • 제4권6호
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    • pp.763-768
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    • 2006
  • The two-for-one(TFO) twister is precision machinery that twists fibers rapidly under constant tension. Since the quality of the twisted yarn is directly deteriorated by faults of the twister, such as the distortion of the spinning axis, bearing abrasion, and tension irregularity, it is important to detect faults of the TFO twister at an early stage. In this research, a new algorithm is proposed to detect faults of the TFO twister and their causes, by measuring the vibrations of the TFO twister and obtaining frequency components with a FFT algorithm. The TFO twister with faults showed increased vibrations and each fault generated vibrations at different frequencies. By analyzing changes of characteristics of vibrations, we can determine faulty twisters. The proposed fault detection algorithm can be implemented cheaply with a signal processor chip. It can be used to find when to repair a faulty TFO twister without much loss of yam on-line.

공작기계의 지능형 고장진단과 원격 서비스 모델 (Model of Remote Service and Intelligent Fault Diagnosis for CNC Machine Tool)

  • 김선호;김동훈;한기상;김찬봉
    • 한국정밀공학회지
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    • 제19권4호
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    • pp.168-178
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    • 2002
  • The CNC machine toots has two kinds of fault. One is the fault due to degraded parts and the other is the fault due to operation disability. The phenomena of degradation is predictable but the operational fault is unpredictable because it occurred without any warning. The major faults of CNC machine tool are operational faults which are charged over 70%. This paper describes the model of remote service and the intelligent fault diagnosis system to diagnosis operational faults of CNC machine tools. To generalize fault diagnosis, two diagnosis models such as SF(Switching Function) and SSF(Step Switching Function) are proposed. The SF is static model and SSF is dynamic model for expression of fault. The SF and SSF model can be generated using SFG(Switching Function Generator) which is developed in this research. The three major operational faults such as emergency stop error, cycle start disability and machine ready disability are applied to experiment of fault modeling. To remote service of faults fur CNC machine tool, the web server and client system based internet are proposed as the suitable environment. The developed two technologies are implemented with the internal function of open architecture controller. The implemental results for two technologies are presented to validate the proposed scheme.

비선형 계통의 뉴로-퍼지 동정과 이의 고장 진단 시스템에의 적용 (Neuro-Fuzzy Identification for Non-linear System and Its Application to Fault Diagnosis)

  • 김정수;송명현;이기상;김성호
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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    • pp.447-452
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    • 1998
  • A fault is considered as a variation of physical parameters; therefore the design of fault detection and identification(FDI) can be reduced to the parameter identification of a non linear system and to the association of the set of the estimated parameters with the mode of faults. ANFIS(Adaptive Neuro-Fuzzy Inference System) which contains multiple linear models as consequent part is used to model non linear systems. In this paper, we proposes an FDI system for non linear systems using ANFIS. The proposed diagnositc system consists of two ANFISs which operate in two different modes (parallel-and series-parallel mode). It generates the parameter residuals associated with each modes of faults which can be further processed by additional RBF (Radial Basis function) network to identify the faults. The proposed FDI scheme has been tested by simultation on a two-tank system

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탄화규소 휘스커의 (II): 적층결함 (Synthesis of Silicon Carbide Whiskers (II): Stacking Faults)

  • 최헌진;이준근
    • 한국세라믹학회지
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    • 제36권1호
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    • pp.36-42
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    • 1999
  • 2단계 열탄소환원법으로 탄화규소 휘스커를 기상-고상, 2단계, 기상-액상-고상 성장기구로 각각 합성하였다. 그리고 휘스커에 있는 적층결합을 X-ray와 투과전자현미경을 이용하여 분석하였다. 탄화규소 휘스커에 있는 적층결함은 휘스커의 지름과 상관관계가 있는 것으로 나타났다. 즉, 기상-고상, 2단계 성장, 기상-액상-고상 성장기구에 상관없이 지름이 1$\mu\textrm{m}$이하로 작아지는 경우 적층결합이 많아지고, 기상-액상-고상 기구로 성장한 지름이 2$\mu\textrm{m}$보다 큰 경우 적층결함이 거의 없는 것으로 나타났다. 이같은 현상은 휘스커 지름이 작아짐에 따라 휘스커의 비표면적이 증가하는 때문인 것으로 판단되었다.

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이중화 구조를 이용한 비동기 디지털 시스템의 방사선 고장 극복 (A New Hardening Technique Against Radiation Faults in Asynchronous Digital Circuits Using Double Modular Redundancy)

  • 곽성우;양정민
    • 제어로봇시스템학회논문지
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    • 제20권6호
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    • pp.625-630
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    • 2014
  • Asynchronous digital circuits working in military and space environments are often subject to the adverse effects of radiation faults. In this paper, we propose a new hardening technique against radiation faults. The considered digital system has the structure of DMR (Double Modular Redundancy), in which two sub-systems conduct the same work simultaneously. Based on the output feedback, the proposed scheme diagnoses occurrences of radiation faults and realizes immediate recovery to the normal behavior by overriding parts of memory bits of the faulty sub-system. As a case study, the proposed control scheme is applied to an asynchronous dual ring counter implemented in VHDL code.

터보분자펌프용 고장허용 자기베어링 시스템 설계 및 개발 (Design and Implementation of a Fault-Tolerant Magnetic Bearing System For Turbo-Molecular Vacuum Pump)

  • 조성락;노명규;박병철
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.760-765
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    • 2004
  • One of the obstacles for a magnetic bearing to be used in the wide range of industrial applications is the failure modes associated with magnetic bearings, which we don't expect for conventional passive bearings. These failure modes include electric power outage, power amplifier faults, position sensor faults, and the malfunction of controllers. Fault-tolerant magnetic bearing systems have been proposed so that the system can operate in spite of some faults in the system. In this paper, we designed and implemented a fault-tolerant magnetic bearing system for a turbo-molecular vacuum pump. The system can cope with the actuator/amplifier faults as well as the faults in position sensors, which are the two major fault modes in a magnetic bearing system.

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