Ali Abdo

H−/H∞ fault detection filter design for discrete-time Takagi–Sugeno fuzzy system

Abstract In this note, a robust fault detection observer is designed for a T–S (Takagi–Sugeno) fuzzy model with sensor faults and unknown bounded disturbances. The method applies the technique of descriptor systems by considering sensor faults as an auxiliary state variable. The idea is to formulate the robust fault detection observer design as an H − / H ∞ problem. Based on nonquadratic Lyapunov functions, a solution of the considered problem is then given via a Linear Matrix Inequality ( LMI ) formulation. An example is proposed to illustrate the design conditions.

Robust fault detection filter design for uncertain switched systems with adaptive threshold setting

In this paper, the fault detection (FD) problem of uncertain discrete-time switched systems under the constrained switching law and external disturbances is addressed. In the multiple Lyapunov functions (MLF) framework with ℋ-/ℋ∞ performance index, a robust fault detection filter (RFDF) is designed in order to generate a residual signal which is sensitive to the faults and robust against the disturbances. The design method is formulated to be solved by linear matrix inequality (LMI) technique. The main contribution in this paper is to improve the performance of the FD for switched systems by considering switch detection logics. The design of the RFDF is based on the local performance index of each subsystem. An adaptive threshold is set based on both, the bounds of disturbances and the individual performance index for each subsystem.

Design of robust fault detection filter for hybrid switched systems

This paper addresses the problem of design a fault detection system for switched systems with unknown inputs. The residual generator based robust fault detection filter (RFDF) will be used, where the switching signal is assumed to be known, and the continuous states will be estimated, resulting a generation of residual signals for each linear model. Dwell-time constraint will be used to ensure the stability for the switched system. The RFDF design is formulated as optimization problem, and solved iteratively by linear matrix inequality (LMI). Stability is analyzed by using the switched Lyapunov functions. Finally a practical example from lateral vehicle dynamics is provided to illustrate the functionality of the proposed technique.

Fault detection scheme for discrete-time Markov jump linear systems with mode-independent residual

In this paper, the fault detection (FD) scheme for discrete-time Markov jump linear systems (MJLS) with mode-independent residual generator is addressed. A recursive mode-independent Kalman filter (KF) is used as a residual generator for solving FD problem in MJLS, which is subject to the Gaussian disturbances. By utilizing the identification function, the recursive mode-independent KF is formulated in the extended state space form. Once residual signal is generated, it will be evaluated whether faults occur or not. Residual evaluation function is selected such that the maximum fault detection rate (FDR) is achieved, for a given false alarm rate (FAR). An estimation of the residual evaluation function variance in the fault-free case is recursively computed and consequently used for a threshold setting. Finally, a numerical example is given in order to demonstrate the performance of this proposed FD scheme.

Fault detection for switched systems based on a deterministic method

This paper addresses fault detection (FD) issues for switched systems. The basic idea behind the proposed method is to estimate the disturbances and then use it in the evaluation function. The main contributions of this paper are summarized as follows: (1) develop a deterministic method for FD. (2) Improve the fault detection performance. (3) Enhance the fault detectability for the switched systems by utilizing the available information provided by each local sub-model in the residual generation, evaluation and threshold computation. The system under consideration in this paper is linear discrete-time switched systems. A switched residual signal will be generated based on the Parity Space approach. The proposed method will be illustrated by an example.

Integration of Residual Evaluation and Threshold Computation into Switched Fault Detection System

Abstract This paper addresses problems related to the designing a fault detection (FD) for switched systems based on fault detection filter (FDF). The main contribution in this paper is to develop a residual evaluation and threshold computation scheme in an integration approach, to achieve an optimal FD for the switched systems. The basic idea behind this scheme is to utilize the available information provided by each local sub-model in the residual generation and evaluation, by constructing weighting factors, that reflect the effect of each local sub-model. In comparison with the standard FD methods, the proposed scheme will lead to a significant improvement in fault detectability for switched systems. The problem is formulated in the well-established LMI optimization techniques with Multiple Laypunov Functions (MLF).

A fault detection scheme for discrete-time Markov jump linear systems

In this paper, the fault detection (FD) problems for discrete-time Markov jump linear systems (MJLS) are addressed. A scheme for solving FD problem for discrete-time MJLS, which is subject to the Gaussian disturbances, is proposed. The Kalman filter (KF) is used as a residual generator. Once a residual signal is generated, it will be evaluated whether faults occur or not. Residual evaluation function is selected such that the maximum fault detection rate (FDR) is achieved, for a given false alarm rate (FAR). Finally, threshold is computed by using an estimation of the variance of evaluation function in the fault-free case. To demonstrate the performance of this proposed method, a numerical example is given.