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Christopher Edwards - One of the best experts on this subject based on the ideXlab platform.

  • robust fault reconstruction for linear parameter varying systems using sliding mode observers
    International Journal of Robust and Nonlinear Control, 2014
    Co-Authors: Halim Alwi, Christopher Edwards
    Abstract:

    SUMMARY This paper presents a robust fault detection and isolation scheme using a sliding mode observer based on a linear parameter varying system, with fault reconstruction capability. Both actuator and sensor fault reconstruction schemes are considered that possess robustness against a certain class of uncertainty and corrupted measurements. For actuator fault reconstruction, the input distribution matrix (associated with the actuators being monitored) is factorized into fixed and varying components. LMIs are used to design the key observer parameters in order to minimize the effect of uncertainty and measurement corruption on the fault reconstruction signal. The faults are reconstructed using the output Error Injection signal associated with the nonlinear term of the sliding mode observer. For sensor fault reconstruction, the idea is to reformulate the problem into an actuator fault reconstruction scenario so that the same design procedure can be applied. This is achieved by augmenting the original system with the filtered sensors being monitored. Simulations using a full nonlinear model of a large transport aircraft are presented and show good fault reconstruction performance. Copyright © 2013 John Wiley & Sons, Ltd.

  • fault reconstruction using a lpv sliding mode observer for a class of lpv systems
    Journal of The Franklin Institute-engineering and Applied Mathematics, 2012
    Co-Authors: Halim Alwi, Christopher Edwards, Andres Marcos
    Abstract:

    Abstract This paper proposes a new sliding mode observer for fault reconstruction, applicable for a class of linear parameter varying (LPV) systems. Observer schemes for actuator and sensor fault reconstruction are presented. For the actuator fault reconstruction scheme, a virtual system comprising the system matrix and a fixed input distribution matrix is used for the design of the observer. The fixed input distribution matrix is instrumental in simplifying the synthesis procedure to create the observer gains to ensure a stable closed-loop reduced order sliding motion. The ‘output Error Injection signals’ from the observer are used as the basis for reconstructing the fault signals. For the sensor fault observer design, augmenting the LPV system with a filtered version of the faulty measurements allows the sensor fault reconstruction problem to be posed as an actuator fault reconstruction scenario. Simulation tests based on a high-fidelity nonlinear model of a transport aircraft have been used to demonstrate the proposed actuator and sensor FDI schemes. The simulation results show their efficacy.

  • tyre road friction estimation a comparative study
    Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering 222 (12) pp. 2337-2351. (2008), 2008
    Co-Authors: N. Patel, Christopher Edwards, Sarah K. Spurgeon
    Abstract:

    AbstractThis paper proposes a comparative study of three observers: a second-order sliding mode observer, a third-order sliding mode observer, and an adaptive observer. The observers are designed for tyre—road friction coefficient μ estimation during a braking manoeuvre in an automotive vehicle. The second-order sliding mode observer and the third-order sliding mode observer reconstruct the friction coefficient μ using equivalent output Error Injection ideas, while the adaptive observer uses explicit estimates of the road condition parameter as part of the scheme. The new second-order observer that is proposed in this paper is based on a quarter-vehicle representation and is independent of the model used to represent the tyre—road friction. The paper considers a dynamic LuGre friction model, a pseudostatic LuGre friction model, and a parameter-based friction model as a basis for a comparative study.

  • robust sliding mode observer based actuator fault detection and isolation for a class of nonlinear systems
    International Journal of Systems Science, 2008
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    In this article, an actuator fault detection and isolation scheme for a class of nonlinear systems with uncertainty is considered. The uncertainty is allowed to have a nonlinear bound which is a general function of the state variables. A sliding mode observer is first established based on a constrained Lyapunov equation. Then, the equivalent output Error Injection is employed to reconstruct the fault signal using the characteristics of the sliding mode observer and the structure of the uncertainty. The reconstructed signal can approximate the system fault signal to any accuracy even in the presence of a class of uncertainty. Finally, a simulation study on a nonlinear aircraft system is presented to show the effectiveness of the scheme.

  • robust decentralized actuator fault detection and estimation for large scale systems using a sliding mode observer
    International Journal of Control, 2008
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    In this paper, robust decentralized actuator fault detection and estimation is considered for a class of non-linear large-scale systems. A sliding mode observer is proposed together with an appropriate coordinate transformation to find the sliding mode dynamics. Then, based on the features of the observer, a decentralized fault estimation strategy is proposed using an equivalent output Error Injection, and a decentralized reconstruction scheme follows by further exploiting the structure of the uncertainty which is allowed to have non-linear bounds. The estimation and reconstruction signals only depend on the available measured information and thus the proposed strategy can work on-line. The theoretical results which have been obtained are applied to an automated highway system. Simulation shows the feasibility and effectiveness of the proposed scheme.

Jianxing Liu - One of the best experts on this subject based on the ideXlab platform.

  • Robust Model-Based Fault Diagnosis for PEM Fuel Cell Air-Feed System
    IEEE Transactions on Industrial Electronics, 2016
    Co-Authors: Jianxing Liu, Wensheng Luo, Xiaozhan Yang, Ligang Wu
    Abstract:

    In this paper, the design of a nonlinear observer-based fault diagnosis approach for polymer electrolyte membrane (PEM) fuel cell air-feed systems is presented, taking into account a fault scenario of sudden air leak in the air supply manifold. Based on a simplified nonlinear model proposed in the literature, a modified super-twisting (ST) sliding mode algorithm is employed to the observer design. The proposed ST observer can estimate not only the system states, but also the fault signal. Then, the residual signal is computed online from comparisons between the oxygen excess ratio obtained from the system model and the observer system, respectively. Equivalent output Error Injection using the residual signal is able to reconstruct the fault signal, which is critical in both fuel cell control design and fault detection. Finally, the proposed observer-based fault diagnosis approach is implemented on the MATLAB/Simulink environment in order to verify its effectiveness and robustness in the presence of load variation.

  • adaptive second order sliding mode observer based fault reconstruction for pem fuel cell air feed system
    IEEE Transactions on Control Systems and Technology, 2015
    Co-Authors: Salah Laghrouche, Jianxing Liu, Mohamed Harmouche, Fayez Shakil Ahmed, Maxime Wack
    Abstract:

    This paper presents an observer-based fault reconstruction method for PEM fuel cells. This method extends the results of a class of nonlinear uncertain systems with Lipschitz nonlinearities. An adaptive-gain second-order sliding mode (SOSM) observer is developed for observing the system states, where the adaptive law estimates the uncertain parameters. The inherent equivalent output Error Injection feature of SOSM algorithm is then used to reconstruct the fault signal. The performance of the proposed observer is validated through a hardware-in-loop emulator. The experimental results illustrate the feasibility and effectiveness of the proposed approach for application to fuel cell air-feed systems.

Maxime Wack - One of the best experts on this subject based on the ideXlab platform.

  • adaptive second order sliding mode observer based fault reconstruction for pem fuel cell air feed system
    IEEE Transactions on Control Systems and Technology, 2015
    Co-Authors: Salah Laghrouche, Jianxing Liu, Mohamed Harmouche, Fayez Shakil Ahmed, Maxime Wack
    Abstract:

    This paper presents an observer-based fault reconstruction method for PEM fuel cells. This method extends the results of a class of nonlinear uncertain systems with Lipschitz nonlinearities. An adaptive-gain second-order sliding mode (SOSM) observer is developed for observing the system states, where the adaptive law estimates the uncertain parameters. The inherent equivalent output Error Injection feature of SOSM algorithm is then used to reconstruct the fault signal. The performance of the proposed observer is validated through a hardware-in-loop emulator. The experimental results illustrate the feasibility and effectiveness of the proposed approach for application to fuel cell air-feed systems.

Xinggang Yan - One of the best experts on this subject based on the ideXlab platform.

  • robust decentralized actuator fault detection and estimation for large scale systems using a sliding mode observer
    International Journal of Control, 2008
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    In this paper, robust decentralized actuator fault detection and estimation is considered for a class of non-linear large-scale systems. A sliding mode observer is proposed together with an appropriate coordinate transformation to find the sliding mode dynamics. Then, based on the features of the observer, a decentralized fault estimation strategy is proposed using an equivalent output Error Injection, and a decentralized reconstruction scheme follows by further exploiting the structure of the uncertainty which is allowed to have non-linear bounds. The estimation and reconstruction signals only depend on the available measured information and thus the proposed strategy can work on-line. The theoretical results which have been obtained are applied to an automated highway system. Simulation shows the feasibility and effectiveness of the proposed scheme.

  • robust sliding mode observer based actuator fault detection and isolation for a class of nonlinear systems
    International Journal of Systems Science, 2008
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    In this article, an actuator fault detection and isolation scheme for a class of nonlinear systems with uncertainty is considered. The uncertainty is allowed to have a nonlinear bound which is a general function of the state variables. A sliding mode observer is first established based on a constrained Lyapunov equation. Then, the equivalent output Error Injection is employed to reconstruct the fault signal using the characteristics of the sliding mode observer and the structure of the uncertainty. The reconstructed signal can approximate the system fault signal to any accuracy even in the presence of a class of uncertainty. Finally, a simulation study on a nonlinear aircraft system is presented to show the effectiveness of the scheme.

  • brief paper nonlinear robust fault reconstruction and estimation using a sliding mode observer
    Automatica, 2007
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    This paper considers fault detection and estimation issues for a class of nonlinear systems with uncertainty, using an equivalent output Error Injection approach. A particular design of sliding mode observer is presented for which the parameters can be obtained using LMI techniques. A fault estimation approach is presented to estimate the fault and the estimation Error is dependent on the bounds on the uncertainty. For a special class of uncertainty, a fault reconstruction scheme is presented where the reconstructed signal can approximate the fault signal to any accuracy. The proposed fault estimation/reconstruction signals are only based on the available plant input/ouput information and can be calculated on-line. Finally, a simulation study on a robotic arm system is presented to show the effectiveness of the scheme.

  • robust sliding mode observer based actuator fault detection and isolation for a class of nonlinear systems
    Conference on Decision and Control, 2005
    Co-Authors: Xinggang Yan, Christopher Edwards
    Abstract:

    In this paper, an actuator fault detection and isolation scheme for a class of nonlinear systems with uncertainty is considered. The uncertainty is allowed to have a nonlinear bound which is a general function of the state variables. A sliding mode observer is established first based on a constrained Lyapunov equation. Then, the equivalent output Error Injection signal is employed to reconstruct the fault signal using the characteristics of the sliding mode observer and the structure of the uncertainty. Finally, a simulation study of the HIRM aircraft system is presented to show the effectiveness of the scheme.

Jacob A Abraham - One of the best experts on this subject based on the ideXlab platform.

  • esift efficient system for Error Injection
    International On-Line Testing Symposium, 2018
    Co-Authors: Ninghan Tian, Daniel G Saab, Jacob A Abraham
    Abstract:

    Computer use in high dependability applications is rapidly increasing. These applications require the computer to be able to detect, locate, isolate and recover from software, hardware or security attacks Errors. To evaluate the dependability of a computer system design, it is critical to be able to assess its ability to detect, locate, recover from Errors, and to estimate coverage and latencies. Fault-Injection tools play critical role in the evaluation and validation of dependable systems. They generate statistics on Error coverage and latencies. This helps to identify good fault tolerance technique that detects and prevent system failures. In this paper, we present an Efficient Fault Injection System for Transient Fault (ESIFT). ESIFT is based on Python extended GDB which makes ESIFT portable across a wide variety of systems. ESFIT operates at near native speed enabling the dependability evaluation of large system. Unlike traditional techniques which evaluate only the faulty system behavior, ESIFT evaluates, concurrently, both the faulty and the fault-free system behavior. This allows faster Error detection and latency evaluation.

  • rethinking Error Injection for effective resilience
    Asia and South Pacific Design Automation Conference, 2014
    Co-Authors: Shahrzad Mirkhani, S Mitra, Jacob A Abraham
    Abstract:

    Soft Errors, caused by radiation, have become a major challenge in today's computer systems and networking equipment, making it imperative that systems be designed to be resilient to Errors. Error Injection is a powerful approach to evaluate system resilience, and current practice is to inject Errors in architectural registers of processors, program variables of applications, or storage elements in the hardware model. This paper, using answers to frequently asked questions, discusses the need for rethinking conventional approaches to Error Injection, showing data from recent research and our simulation results. Approaches to improving current Error Injections are also suggested.

  • quantitative evaluation of soft Error Injection techniques for robust system design
    Design Automation Conference, 2013
    Co-Authors: Hyungmin Cho, Shahrzad Mirkhani, Jacob A Abraham, Chenyong Cher, S Mitra
    Abstract:

    Choosing the correct Error Injection technique is of primary importance in simulation-based design and evaluation of robust systems that are resilient to soft Errors. Many low-level (e.g., flip-flop-level) Error Injection techniques are generally used for small systems due to long execution times and significant memory requirements. High-level Error Injections at the architecture or memory levels are generally fast but can be inaccurate. Unfortunately, there exists very little research literature on quantitative analysis of the inaccuracies associated with high-level Error Injection techniques. In this paper, we use simulation and emulation results to understand the accuracy trade-offs associated with a variety of high-level Error Injection techniques. A detailed analysis of Error propagation explains the causes of high degrees of inaccuracies associated with Error Injection techniques at higher levels of abstraction.

  • design and evaluation of system level checks for on line control flow Error detection
    IEEE Transactions on Parallel and Distributed Systems, 1999
    Co-Authors: Z Alkhalifa, V S S Nair, N Krishnamurthy, Jacob A Abraham
    Abstract:

    This paper evaluates the concurrent Error detection capabilities of system-level checks, using fault and Error Injection. The checks comprise application and system level mechanisms to detect control flow Errors. We propose Enhanced Control-Flow Checking Using Assertions (ECCA). In ECCA, branch-free intervals (BFI) in a given high or intermediate level program are identified and the entry and exit points of the intervals are determined. BFls are then grouped into blocks, the size of which is determined through a performance/overhead analysis. The blocks are then fortified with preinserted assertions. For the high level ECCA, we describe an implementation of ECCA through a preprocessor that will automatically insert the necessary assertions into the program. Then, we describe the intermediate implementation possible through modifications made on gee to make it ECCA capable. The fault detection capabilities of the checks are evaluated both analytically and experimentally. Fault Injection experiments are conducted using FERRARI to determine the fault coverage of the proposed techniques.

  • ferrari a flexible software based fault and Error Injection system
    IEEE Transactions on Computers, 1995
    Co-Authors: G A Kanawati, N A Kanawati, Jacob A Abraham
    Abstract:

    A major step toward the development of fault-tolerant computer systems is the validation of the dependability properties of these systems. Fault/Error Injection has been recognized as a powerful approach to validate the fault tolerance mechanisms of a system and to obtain statistics on parameters such as coverages and latencies. This paper describes the methodology and guidelines for the design of flexible software based fault and Error Injection and presents a tool, FERRARI, that incorporates the techniques. The techniques used to emulate transient Errors and permanent faults in software are described in detail. Experimental results are presented for several Error detection techniques, and they demonstrate the effectiveness of the software-based Error Injection tool in evaluating the dependability properties of complex systems. >