Chokri Mechmeche

Bio: Chokri Mechmeche is an academic researcher from École Polytechnique. The author has contributed to research in topics: Observer (quantum physics) & Fault detection and isolation. The author has an hindex of 10, co-authored 17 publications receiving 327 citations. Previous affiliations of Chokri Mechmeche include Institut national des sciences appliquées.

Fault detection and isolation in linear parameter-varying descriptor systems via proportional integral observer

Abstract: SUMMARY The main contribution of this paper is the design of a polytopic Unknown Input Proportional Integral Observer (UIPIO) for Linear Varying Parameter (LPV) descriptor systems. This observer is used for actuator Fault Detection and Isolation (FDI). The proposed method is based on the representation of LPV descriptor systems in polytopic form where its parameters evolve in a hypercube domain. The designed polytopic UIPIO is also able to estimate the states and the unknown inputs of the LPV descriptor system. Stability conditions of such observer are expressed in terms of Linear Matrix Inequalities (LMI). An example illustrates the performances of such polytopic UIPIO for multiple actuator faults estimation in spite of disturbances. Copyright c 2011 John Wiley & Sons, Ltd.

Robust Fault Detection and Estimation for Descriptor Systems based on Multi-Models Concept

Abstract: This paper addresses the robust fault detection and estimation problem of nonlinear descriptor system with unknown inputs observers. The considered nonlinear descriptor system is transformed into an equivalent multi-models form by using the Takagi-Sugeno (T-S) approach. Two cases are considered: the first one deals with the multi-models based on measurable decision variables and the second one assumes that these decision variables are unmeasurable. Then, a residual generator based on an unknown observer is designed for both fault detection and estimation. Stability analysis and gain matrices determination are performed by resolving a set of Linear Matrices Inequalities (LMIs) for both cases. The performances of the proposed fault detection and estimation method is successfully applied to an electrical circuit.

T-S fuzzy bilinear observer for a class of nonlinear system

Abstract: This paper deals with a fuzzy bilinear observer design for a class of nonlinear systems. The nonlinear system is modeled as a Takagi-Sugeno fuzzy bilinear model. The observer stability is assured irrespective of the inputs and stability conditions are expressed in terms of Linear Matrix Inequality (LMI). A numerical example is given to demonstrate the effectiveness of the proposed Takagi-Sugeno Fuzzy Bilinear Observer (T-S FBO).

Unknown Input Observer Design for Fuzzy Bilinear System: An LMI Approach

Abstract: A new method to design a fuzzy bilinear observer (FBO) with unknown inputs is developed for a class of nonlinear systems. The nonlinear system is modeled as a fuzzy bilinear model (FBM). This kind of T-S fuzzy model is especially suitable for a nonlinear system with a bilinear term. The proposed fuzzy bilinear observer subject to unknown inputs is developed to ensure the asymptotic convergence of the error dynamic using the Lyapunov method. The proposed design conditions are given in linear matrix inequality (LMI) formulation. The paper studies also the problem of fault detection and isolation. An unknown input fuzzy bilinear fault diagnosis observer design is proposed. This work is given for both continuous and discrete cases of fuzzy bilinear models. Illustrative examples are chosen to provide the effectiveness of the given methodology.

Fault detection and isolation in linear parameter-varying descriptor systems via proportional integral observer

Abstract: SUMMARY The main contribution of this paper is the design of a polytopic Unknown Input Proportional Integral Observer (UIPIO) for Linear Varying Parameter (LPV) descriptor systems. This observer is used for actuator Fault Detection and Isolation (FDI). The proposed method is based on the representation of LPV descriptor systems in polytopic form where its parameters evolve in a hypercube domain. The designed polytopic UIPIO is also able to estimate the states and the unknown inputs of the LPV descriptor system. Stability conditions of such observer are expressed in terms of Linear Matrix Inequalities (LMI). An example illustrates the performances of such polytopic UIPIO for multiple actuator faults estimation in spite of disturbances. Copyright c 2011 John Wiley & Sons, Ltd.

Actuator fault estimation based adaptive polytopic observer for a class of LPV descriptor systems

Abstract: This paper presents an Adaptive Polytopic Observer (APO) design in order to develop an actuator fault estimation method dedicated to polytopic Linear Parameter Varying (LPV) descriptor systems. This paper extends a fault diagnosis method developed for regular LTI systems to polytopic LPV descriptor systems. Here, time-varying actuator faults are also considered, whereas in many papers, actuator faults are generally assumed to be constant. The design and convergence conditions of this APO are provided. The design is formulated through LMI techniques under equality constraints. The performances of the proposed actuator fault estimation scheme are illustrated using an electrical circuit.

Actuator fault estimation observer design for discrete-time linear parameter-varying descriptor systems

Abstract: SUMMARY This paper deals with actuator fault estimation for a class of discrete-time Linear Parameter-Varying (LPV) descriptor systems. By considering the fault as an auxiliary state vector, an augmented system is established. Then, a fault estimation observer is designed based on the augmented system. In this paper, the fault estimation observer design is formulated as a Linear Matrix Inequality (LMI) feasibility problem. Therefore, all parameters of the observer can be simultaneously designed by solving a set of strict LMIs. In order to attenuate the effect of the unknown disturbance, fault variation, and measurement noise, we further propose a robust fault estimation observer design method, which is the main contribution of this paper. Finally, performance of the proposed robust fault estimation observer is shown through the application to a trucktrailer model. Copyright c ⃝ 2013 John Wiley & Sons, Ltd.

Observer-based Fault Tolerant Control Design for a Class of LPV Descriptor Systems

Abstract: This paper presents a new Fault Tolerant Control (FTC) methodology for a class of LPV descriptor systems that are represented under a polytopic LPV form. The aim of this FTC strategy is to compensate the effects of time-varying or constant actuator faults by designing an Adaptive Polytopic Observer (APO) which is able to estimate both the states of the system and the magnitude of the actuator faults. Based on the information provided by this APO, a new state feedback control law is derived in order to stabilize the system. Stability conditions of the designed observer and the state-feedback control are provided and solved through a set of Linear Matrix Inequalities (LMI) under equality constraints. The performance of the proposed Fault Tolerant Control scheme is illustrated using a two-phase flash system.