• Title/Summary/Keyword: Fault Accommodation

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Accommodation Rule Based on Navigation Accuracy for Double Faults in Redundant Inertial Sensor Systems

  • Yang, Cheol-Kwan;Shim, Duk-Sun
    • International Journal of Control, Automation, and Systems
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    • v.5 no.3
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    • pp.329-336
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    • 2007
  • This paper considers a fault accommodation problem for inertial navigation systems (INS) that have redundant inertial sensors such as gyroscopes and accelerometers. It is wellknown that the more sensors are used, the smaller the navigation error of INS is, which means that the error covariance of the position estimate becomes less. Thus, when it is decided that double faults occur in the inertial sensors due to fault detection and isolation (FDI), it is necessary to decide whether the faulty sensors should be excluded or not. A new accommodation rule for double faults is proposed based on the error covariance of triad-solution of redundant inertial sensors, which is related to the navigation accuracy of INS. The proposed accommodation rule provides decision rules to determine which sensors should be excluded among faulty sensors. Monte Carlo simulation is performed for dodecahedron configuration, in which case the proposed accommodation rule can be drawn in the decision space of the two-dimensional Cartesian coordinate system.

Fault Diagnosis and Accommodation of Linear Stochastic Systems with Unknown Disturbances

  • Lee, Jong-Hyo;Joon Lyou
    • Transactions on Control, Automation and Systems Engineering
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    • v.4 no.4
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    • pp.270-276
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    • 2002
  • An integrated robust fault diagnosis and fault accommodation strategy for a class of linear stochastic systems subjected to unknown disturbances is presented under the assumption that only a single fault may occur at a given time. The strategy is based on the fault isolation and estimation using a bank of robust two-stage Kalman filters and introduction of the additive compensation input for cancelling out the fault's effect on the system. Each filter is set up such that the residual is decoupled from unknown disturbances and fault with the influence vector designed in the filter. Simulation results for the simplified longitudinal flight control system with parameter uncertainties, process and sensor noises demonstrate the effectiveness of the present approach.

Adaptive Fault Accommodation Control for Flexible-Joint Robots (유연 관절 로봇의 적응 고장 수용 제어)

  • Yoo, Sung Jin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.1
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    • pp.46-50
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    • 2013
  • This paper proposes an adaptive fault accommodation control approach for flexible-joint (FJ) robots with multiple actuator faults. It is assumed that the value and occurrence time of multiple actuator faults are unknown. An adaptive fault accommodation control scheme with prescribed performance bounds, which characterize the convergence rate and maximum overshoot of tracking errors, is designed to accommodate the actuator faults. From the Lyapunov stability theorem, it is proved that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and tracking errors are preserved within prescribed performance bounds regardless of actuator faults.

On Fault Handling in Control Systems

  • Staroswiecki, Marcel
    • International Journal of Control, Automation, and Systems
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    • v.6 no.3
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    • pp.296-305
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    • 2008
  • Whereas fault diagnosis has been the subject of intensive research since the 1970s, the design of fault tolerant systems is a recent research field which does not set its foundations in a unified framework and does not use a unified vocabulary. As a contribution to this special issue, this paper proposes an ontology for the problem of Fault Handling, that embeds the problem of Fault Tolerance.

A study on the control surface/actuator fault detection, identification, and accommodation system for aircraft (항공기 제어면/구동장치 고장에 대한 진단규명 및 보완 제어시스템 설계에 관한 연구)

  • Song, Yong-Kyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.7
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    • pp.61-67
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    • 2002
  • In this study a control surface/actuator fault detection, identification, and accommodation system for aircraft is designed. This fault tolerant control system tries to return aircraft to its stable trim condition in a short time. The control system is designed using neural networks with Extended Back Propagation Algorithm which shows fast convergence. F-4 aircraft with possible stabilator or aileron failure/stuck is simulated with the proposed scheme.

Third Order Sliding Mode Observer based Robust Fault Diagnosis for Robot Manipulators (3 계 슬라이딩 모드 관측기 기반 로봇 고장 진단)

  • Van, Mien;Kang, Hee-Jun;Suh, Young-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.7
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    • pp.669-672
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    • 2012
  • This paper investigates an algorithm for robust fault diagnosis in robot manipulators. The TOSM (Third Order Sliding Mode observer) provides both theoretically exact observation and unknown fault identification without filtration. The EOI (Equivalent Output Injections) of the TOSM observers can be used as residuals for the problem of fault diagnosis and to identify the unknown faults. The obtained fault information can be used for fault detection, isolation as well as fault accommodation to the self-correcting failure system. The computer simulation results for a PUMA 560 robot are shown to verify the effectiveness of the proposed strategy.

Observer Design for Robust Process Fault Estimation (견실한 프로세스 고장추정을 위한 관측기 설계)

  • Park, Tae-Geon;Lee, Kee-Sang
    • Proceedings of the KIEE Conference
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    • 2004.07d
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    • pp.2182-2184
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    • 2004
  • This paper presents a systematic and straightforward fault estimation approach for process fault detection. isolation and accommodation. The approach includes the design of a reduced-order observer and an algebraic-fault estimator. The observer is designed for an unknown input and fault-free system, which is obtained by coordinate transformations of original systems with unknown inputs and faults. The observer information is devoted to- the fault estimation for fault detection and isolation. The fault estimates can be used to form an additional control input to accommodate the fault. The suggested scheme is verified through simulation studies performed on the control of a vertical takeoff and landing (VTOL) aircraft in the vertical plane.

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Fault Tolerant Controller Design for Linear Stochastic Systems with Uncertainties (불확실성을 갖는 선형 확률적 시스템에 대한 고장허용제어기 설계)

  • Lee, Jong-Hyo;Yoo, Jun
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.2
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    • pp.107-116
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    • 2003
  • This paper presents a systematic design methodology for fault tolerant controller against a fault in actuators and sensors of linear stochastic systems with uncertainties. The scheme is based on fault detection and diagnosis(isolation and estimation) using a bank of robust two-stage Kalman filters, and accommodation of the actuator fault by eigenstructure assignment and immediate compensation of the sensor's faulty measurement. In order to clarify the fault feature in test statistics of residual, noise reduction method is given by multi-scale discrete wavelet transform. The effectiveness of our approach Is shown via simulations for a VTOL(vertical take-off and landing) aircraft subjected to parameter variations, external disturbances, process and sensor noises.

Sensor Failure Detection and Accommodation Based on Neural Networks (신경회로망을 이용한 센서 고장진단 및 극복)

  • 이균정;이봉기
    • Journal of the Korea Institute of Military Science and Technology
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    • v.1 no.1
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    • pp.82-91
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    • 1998
  • This paper presents a neural networks based approach for the problem of sensor failure detection and accommodation for ship without physical redundancy in the sensors. The designed model consists of two neural networks. The first neural network is responsible for the failure detection and the second neural network is responsible for the failure identification and accommodation. On the yaw rate sensor of ship, simulation results indicates that the proposed method can be useful as failure detector and sensor estimator.

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Integrating Fuzzy based Fault diagnosis with Constrained Model Predictive Control for Industrial Applications

  • Mani, Geetha;Sivaraman, Natarajan
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.886-889
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    • 2017
  • An active Fault Tolerant Model Predictive Control (FTMPC) using Fuzzy scheduler is developed. Fault tolerant Control (FTC) system stages are broadly classified into two namely Fault Detection and Isolation (FDI) and fault accommodation. Basically, the faults are identified by means of state estimation techniques. Then using the decision based approach it is isolated. This is usually performed using soft computing techniques. Fuzzy Decision Making (FDM) system classifies the faults. After identification and classification of the faults, the model is selected by using the information obtained from FDI. Then this model is fed into FTC in the form of MPC scheme by Takagi-Sugeno Fuzzy scheduler. The Fault tolerance is performed by switching the appropriate model for each identified faults. Thus by incorporating the fuzzy scheduled based FTC it becomes more efficient. The system will be thereafter able to detect the faults, isolate it and also able to accommodate the faults in the sensors and actuators of the Continuous Stirred Tank Reactor (CSTR) process while the conventional MPC does not have the ability to perform it.