Kamel Abderrahim

University of Gabès · Electrical Engineering Department

In this article, we propose an approach for system identification for a class of discrete-time fractional-order Hammerstein systems using only input–output data. Using a combined state and parameter estimation approach, we develop an algorithm serving to estimate simultaneously, the system parameters, the system orders, and the system states. By mi...

This paper deals with the Finite-Time Boundedness (FTB) of linear time-invariant systems that are affected by a disturbance generated by an exosystem. By using a time-invariant quadratic Lyapunov function, Finsler's lemma and a dual system approach, new sufficient LMIs conditions are given for analysis and synthesis for FTB. These results are exten...

Over the past few decades, there have been increasing research activities in fault diagnosis (FD) and fault-tolerant control (FTC) for switched hybrid systems. This paper addresses the problem of active-fault tolerant control (AFTC) for switched hybrid systems subject to actuator faults to enhance system security and keep system stability. The prop...

The main objective of this paper is the control of the voltage of a DC generator. Tothis aim, firstly, we identify the system using PieceWise Auto-Regressive eXogenous (PWARX)models due to their ability to approximate any nonlinear system with arbitrary precision.Secondly, we propose to design the one-step-ahead predictive control based on the iden...

The design of an accurate fault-tolerant control fault-tolerant control is still an active researches of switched hybrid system whose switching mechanism is unknown. In this paper, a new approach is proposed to deal with switching mode estimation and control problems for switched system subject to actuator faults and disturbances. First, the switch...

This paper addresses both the problems of identification and state estimation of the class of nonlinear fractional systems. Using the combined state and parameter estimation approach, a new method of estimation serving to estimate simultaneously the unknown parameters, the unknown fractional orders and the inaccessible states, is proposed for the d...

In this paper, the estimation problem is considered for both sample delay and coefficients of ARMAX model. An extended recursive least squares algorithm is derived by minimizing a quadratic cost function. However, the solution of the optimization problem returns a real value for the sample delay. To overcome this difficulty, the rounding properties...

Jointly identification of the sample delay and the parameters of time-delay discrete-time ARMAX models are addressed in this article. Like any identified problem, the proposed approach is based on the solution of an optimization problem. It consists then of two main steps: the first is the problem formulation and the second is the problem resolutio...

This paper aims to design of an active fault-tolerant control AFTC of switched systems in the presence of sensor fault and periodic disturbances. AFTC requires sensor fault estimation. Thus, a data-based projection approach is proposed based on performance measures that allow fault estimation without relying on mathematical models and fault assumpt...

In this paper, a new robust model predictive control (RMPC) is proposed for uncertain nonlinear systems. The nonlinear behavior is described by uncertain piecewise affine models, where the parametric uncertainties are considered time varying with norm-bounded structure. The proposed control scheme consists of two steps. First, a proportional gain o...

For the fractional-order Hammerstein system with white noise, the difficulty of identification is that the parameters of the linear and the nonlinear blocks and the fractional order are unknown and the intermediate variable and the states are unmeasurable. To overcome this difficulty, we transform the system from an input nonlinear pseudo-state-spa...

This paper concerns the identification of a transesterification reactor using PWARX (PieceWise AutoRegressive eXogenous) hybrid systems. The OBE (Outer Bounding Ellipsoid) algorithm is then applied in order to estimate the parameters for each sub-system. This algorithm is used for system identification when bounded disturbances are present. This pa...

Two adaptive blind equalization algorithms for M-QAM modulation of a Single Input Single Output (SISO) are presented. The second blind equalization algorithm is an extension of the first algorithm. These methods are tested in a wireless environment where the noise is bounded and the channel is multipath fading. The two proposed equalizers are based...

New developments for parameter and time-delay identification are presented for discrete nonlinear systems with delayed input. The proposed approach is based on overparametrization approach which involves subsuming the delay term into an extended numerator polynomial of the linear block of Wiener time-delay system. On this basis, the parameter ident...

This paper deals with the problem of identification of fractional-order Wiener systems. This model consists of a linear fractional-order state space system in series with a static nonlinear block. This problem poses different difficulties, because, it consists of estimating the system parameters and the fractional order. In this work, a new identif...

It is quite challenging to identify in one step a nonlinear model with time delay due to the nonlinear relationship between the time delay and the other model parameters. Therefore, a two step procedure for estimating the system parameters and the time delay is proposed in this paper: The first step is to estimate the parameter vector using the gra...

In this paper, the problem of hybrid model predictive control (HMPC) strategy based on fuzzy supervisor for piecewise autoregressive with exogenous input (PWARX) models is addressed. We first represent the nonlinear behavior of the system with a PWARX model. Then, we transform the obtained PWARX model into a mixed logical dynamic (MLD) model in ord...

This paper investigates the synthesis of less conservative conditions for finite-time stabilization of linear continuous time-invariant systems. For this purpose, we tackle the problem with a S-Variable approach. The latter approach is widely used in the context of robust stability. It had recognized a great sucks in the community of automatic. The...

This paper deals with the design of an H_Inf adaptive observer with a reduced order for a class of bilinear time delay systems. The proposed observers allow the joint estimation of the state and the unknown parameter vectors. A LyapunovKrasovskii approach is used to deduce the stability conditions, given in terms of the solvability of Linear Matrix...

This work deals with the design of functional observer for a bilinear time delay system. The system under consideration presents some bounded energy perturbations in its dynamics. In this context, an H1 approach is used to provide a guaranteed disturbances attenuation level. Within this paper, the observation problem is formulated as the stability...

In this paper, we consider the problems of nonlinear system representation and control. In fact, we propose a solution based on PieceWise Auto-Regressive eXogenous (PWARX) models since these models are able to approximate any nonlinear behaviour with arbitrary precision. Moreover, the identification and control approaches of linear systems can be e...

Dans ce travail, on s’intéresse à la stratégie de commande prédictive MPC (Model Predictive Control) appliquée aux systèmes hybrides. C’est une méthode qui a connu un grand succès pour la commande des procédés industriels et largement appliquée avec des dynamiques linéaires ou non linéaires [55, 100]. Sa popularité est liée à la capacité d’exiger d...

This paper deals with the problem of identification of fractional Hammerstein systems. This model consists of a static nonlinear block in series with a linear fractional-order state space system. This problem poses different difficulties, because, it consists of estimating the system parameters, the states and the fractional order. To simplify this...

A main topics in modern wireless communication systems is the development of equalization algorithms for different single-carrier modulations. This paper lists the most important blind equalization techniques for single-carrier modulations. A detailed study of some of these most used approaches in the literature is presented, in particular their pr...

This paper deals with the problem of switched linear system identification. This is one of the most difficult problems since it involves both the estimation of the linear sub-models and the switching instants. In fact, we propose an identification approach based on self-adaptation multi-kernel clustering algorithm to estimate simultaneously the lin...

This paper deals with the problem of switched linear system identification. This is one of the most difficult problems since it involves both the estimation of the linear sub-models and the switching instants. In fact, we propose an identification approach based on self-adaptation multi-kernel clustering algorithm to estimate simultaneously the lin...

This paper deals with the problem of switched linear system identification. This is one of the most difficult problems since it involves both the estimation of the linear sub-models and the switching instants. In fact, we propose an identification approach based on self-adaptation multi-kernel clustering algorithm to estimate simultaneously the lin...

This work deals with the design of functional observer for a bilinear time-delay system. The system under consideration presents some bounded energy perturbations in its dynamics. In this context, an H∞ approach is used to provide a guaranteed disturbances attenuation level. Within this chapter, the observation problem is formulated as the stabilit...

This chapter deals with the design of an H∞ adaptive observer with a reduced order for a class of bilinear time-delay systems. The proposed observers allow the joint estimation of the state and the unknown parameter vectors. A Lyapunov-Krasovskii approach is used to deduce the stability conditions, given in terms of the solvability of linear matrix...

In automatic control reaserch fields, an observer plays a key role in the control and supervision of processes or the detection of faults, given its ability to provide information on the values of unmeasured or unavailable states. In this context, this thesis deals with the estimation not only of the state but also of the estimation of the unknown...

Two adaptive blind equalization algorithms for M-QAM modulation of a Single Input Single Output (SISO) are presented. The second blind equalization algorithm is an extension of the first algorithm. These methods are tested in a wireless environment where the noise is bounded and the channel is multipath fading. The two proposed equalizers are based...

This paper deals with the design of adaptive observer for a class of bilinear time delay systems. First, this problem is investigated in the full order case and and it is then extended to the reduced order one. The proposed observers allow the joint estimation of the state and the unknown parameter vectors. A Lyapunov-Krasovskii approach is used to...

Dans cet article, nous mettons l'accent sur le problème d'une commande basée observateur pour une génératrice asynchrone à double alimentation (DFIG) modélisée par un système à paramètres variants (Linear Parameter Varying system: LPV system) pilotée par une éolienne (DFIGWT). L'intérêt est de pouvoir contrôler un système de production d'électricit...

Provide equalization algorithms for orthogonal frequency division multiplexing (OFDM) signals transmitted over multipath channels with different type of constellations, is one of the most important works in modern wireless communication systems at high speed, for its great role to reduce Intersymbol-interference (ISI). This article recalls the tech...

In this paper, we point out the problem of an observer-based control design for a Doubly-Fed Induction Generator (DFIG) driven by a Wind Turbine (DFIGWT). The interest is to be able to control a poxer generation system even if we do not have access to all the measures. Based on a state space modelization of a DFIGWT, sufficient conditions of a stat...

This paper addresses the blind equalization problem in presence of bounded noise using an optimal bounding ellipsoid (OB) algorithm. This provides an adequate blind equalization algorithm with an accurate parameter estimation. A fundamental analysis of the involved equalizer is performed to emphasize its underlying properties. This fundamental resu...

This work focus on practical implementation of remote control. Adaptive and internal model control (IMC) strategies have been adopted. Thus, the adaptive auto-adjustable controller is based on pole placement control method and the hierarchical identification strategy. Bluetooth has been used as wireless communication protocol. Practical results for...

In this paper, a fault tolerant control (FTC) strategy for disturbed switched hybrid system subject to actuator fault is proposed. In fact, the fault signal estimation is ensured by extending the data-based projection method (EDPM). Then, the fault tolerant control is designed by combining the state feedback control with integral action with an add...

This paper deals with the design of adaptive observer for a class of nonlinear systems with time delays. Within this work, we develop an adaptive observer for a bilinear time delay system, then we extend those results in the presence of Lipschitz nonlinear functions in the system’s dynamics. In the stability analysis of the estimation errors, we co...

The present work treats the problem of actuator fault tolerant control (FTC) for disturbed switched hybrid system. By extending the data-projection method (EDPM), the fault signal is estimated fast and properly. Then, using the unknown input observers, the unavailable state is estimated. Based on the estimated state and fault estimation information...

The present work treats the problem of actuator fault tolerant control (FTC) for disturbed switched hybrid system. By extending the data-projection method (EDPM), the fault signal is estimated fast and properly. Then, using the unknown input observers, the unavailable state is estimated. Based on the estimated state and fault estimation information...

In this paper, we propose a frequency recursive blind equalization algorithm of data in orthogonal frequency division multiplexing (OFDM) system using a cyclic prefix. The proposed algorithm is based on a Set Membership identification methods. More precisely, it is based an Optimal Bounding Ellipsoid (OBE) algorithm. In this document, we consider t...

This paper addresses the problem of sensor fault estimation and compensation of switched hybrid systems. Indeed, we propose to extend the Data-based Projection Method (EDPM) for the switched system in order to estimate the fault. The fault compensation is ensured by a fault tolerant control (FTC) based on the EDPM. This FTC is performed by combinin...

This paper deals with the problem of nonlinear systems control. In fact, we propose an alternative solution based on Piecewise AutoRegressive with eXogenous input (PWARX) model, Hybrid Model Predictive Control (HMPC) strategy and fuzzy supervisor. The contribution consists in introducing a fuzzy supervisor allowing the online readjustment of the HM...

In order to estimate simultaneously the states and the unknown parameters in a dynamic system, we adress in this work the problem of the design of an adaptive observer. As a generalization of some previous works, we consider here, the bilinear descriptor time delay systems. Sufficient conditions for the existence of the proposed observer are given....

This paper proposes a method for the design of a robust functional H∞ observer for a class of time delay bilinear systems. The considered system is affected by norm-bounded uncertainties in the system matrices and an unmeasured perturbations which are of finite energy. The unbiasedness conditions on the nominal part of the error dynamics of the pro...

A Hammerstein-Wiener model with time delay is a specific class of nonlinear time delay systems where the time delay which involves the system input and the parameters are unknown and need to be estimated using input-output data. The main difficulty that has been encountered in this identification problem is the additional nonlinearity due to the pr...

This paper deals with the problem of the design of a functional adaptive observer for a class of bilinear time delay systems. Both the states and the unknown parameters will be estimated via the proposed observer. The system under consideration presents some bounded energy perturbations in its dynamics. For this reason, an H∞ approach was used to p...

In this paper, the problem of finite time control via a dynamic output feedback controller for continuous time invariant linear systems is addressed. The obtained controller ensure that the closed-loop system is finite-time bounded. Using a descriptor system approach, the design conditions are expressed in term of Linear Matrix Inequalities (LMIs).

The present study investigates the synthesis of sufficient conditions for finite-time boundedness and stabilisation of non-linear quadratic systems with exogenous disturbances. For this purpose, the usefulness of combining the notion of annihilator with a version of Finsler's lemma has been investigated. The obtained design conditions are expressed...

Dans ce travail, nous présentons la conception d'observateur pour un modèle de système biologique : le modèle proie-prédateur, dit aussi Lotka-Volterra. Dans un premier temps, nous faisons un retour sur des travaux récents pour la conception d'observateurs pour ces systèmes. Dans un second temps, nous proposons un observateur permettant l'estimatio...

In the present work, we proposed a novel approach which allows the estimation of actuator fault and its compensation correctly for switched hybrid system. So, to thwart the impact of the fault we extended and developed a fault tolerant control (FTC) for switched system. The synthesis of it needs to follow three important steps. The first step, is b...

In this paper, we provide two algorithms for blind equalization in a bounded noise environment of a Single Input Single Output (SISO) channel. These approaches are based an Optimal Bounding Ellipsoid (OBE) algorithms. This class is among the set Membership identification methods. The aim of these algorithms is to force the equalizer output constell...

The present study investigates the synthesis of sufficient conditions for finite-time boundedness and stabilisation of non-linear quadratic systems with exogenous disturbances. For this purpose, the usefulness of combining the notion of annihilator with a version of Finsler's lemma has been investigated. The obtained design conditions are expressed...

A Functional Adaptive Observer (FAO) for a bilinear system with multiple discrete delays, is proposed in this paper. This observer allow the simultaneous estimation of the states and the unknown parameter. Necessary and sufficient conditions of unbiasedness of the functional observer are given. Stability conditions, which depend on system’s delays,...

This paper deals with the problem of identification of Hammerstein time delay systems. In fact, we propose a Hierarchical optimization based approach allowing to estimate simultaneously the time delay, the linear dynamic parameters and the nonlinear static parameters of such systems. This approach consists, firstly, in decomposing a complex nonline...

This document surveys the blind equalization issue. Our approach is based on the reformulation of the equalization problem in an identification problem in existence of limited noise. The objective of the proposed method is to estimate the settings of the equalizer such that the output of the equalizer is in a neighborhood of the input constellation...

In this paper, a novel optimization approach to estimate the time delay and the parameters of Wiener time-delay systems is proposed. The proposed method consists first in defining a cost function and second in selecting an appropriate algorithm to solve it. However, any used cost function for the purpose of Wiener time-delay system identification p...

This paper deals with the problem of identification of Wiener systems with unknown integer time delay. This problem presents several difficulties, since it consists in estimating simultaneously the integer time delay, the parameters of the linear dynamic subsystem and the parameters of the non-linear static block. To overcome these difficulties, we...

In this paper, we proposed a new way that allows the identification and the compensation of sensor fault at the same time for hybrid switched systems. Indeed, to compensate this fault we chose the additive fault tolerant control (FTC). The synthesis of this FTC requires two important stages. The first step, provide the estimation of the fault by us...

The work presented in this paper deals with the active mode identification problem for switched linear systems based on a measurement data set. This problem is an issue closely related to the classification problem of input-output measure data. Indeed, each data group associated with their most appropriate sub-model presents a mode (discrete state)...

In this paper, a nonlinear hybrid system predictive control approach is developped. Hybrid process identification is based on PieceWise AutoRegressive eXogenous (PWARX) models. The identificaion problem deals with Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm. Model Predictive Control (MPC) strategy is based on Mixe...

According to the Hierarchical identification principle, the auxiliary model approach and the rounding properties, we derive a recursive algorithm for the identification of Wiener time delay systems. The main idea of the proposed algorithm consists in decomposing the nonlinear cost function into two cost functions. The gradient and the Levenberg Mar...

This paper investigates the synthesis of sufficient conditions for finite-time stabilization of nonlinear quadratic systems via a nonlinear static state controller. For this purpose, we consider polytopic domains rather than ellipsoidal domains, and we investigate the usefulness of combining the notion of annihilator with a version of Finsler's Lem...

We consider the problem of switched linear system identification from input-output data set. This set may be a mixte set whose data are generated from a different switching affine subsystems so that one does not know a priori or a switching dynamics is unavailable. To overcome this main challenge, we develop an identification approach which consist...

According to the Hierarchical identification principle, the auxiliary model approach and the rounding properties, we derive a recursive algorithm for the identification of Wiener time delay systems. The main idea of the proposed algorithm consists in decomposing the nonlinear cost function into two cost functions. The gradient and the Levenberg Mar...

In this paper, an algorithm is developed for the identification of the time delay parameter and the dynamic parameters of autoregressive moving average with exogenous input ARMAX time delay models. This algorithm consists in constructing a linear-parameter formulation by building a generalized vector observation and using the recursive least square...

In this paper, a new method for the detection of switching time is proposed for discrete-time linear switched systems, whose switching mechanism is unknown. The switching instant estimation problem consists to predict the mode switching for discrete behavior from a finite set of input–output data. First, the proposed method use a clustering and cla...

This paper investigates the synthesis of full order output dynamic controller for linear continuous system with norm-bounded disturbances. This controller ensures the finite time boundedness of the closed loop system and satisfies the ℋ ∞ criterion. The design conditions obtained by means of Lyapunov functions are expressed in term of linear matrix...

A new general relationship between cumulants and impulse response coefficients of the FIR systems is presented. This relation can be used to unify several of the FIR coefficients estimation algorithms proposed in the literature. It can be further used to develop a new estimation method. This relation is illustrated with a few examples.

This paper focuses on the identification problem of Hammerstein nonlinear systems with delayed input. This problem involves both the estimation of the time delay and the parameters by applying respectively the Variable Regression Estimation (VRE) technique and the gradient approach. Simulation results are presented to illustrate the the performance...

In this paper, we address the problem of state estimation of linear switched discrete time models from a finite set of input-output data. This is a challenging problem since it requires estimating the active discrete state and its continuous observer. In fact, we propose a hybrid state observer design which consists of two stages. The first allows...

In this paper, we propose a hierarchical gradient based algorithm to identify simultaneously the parameters of the linear and nonlinear blocks and the time delay of Wiener time delay systems. We separate the nonlinear cost function into two cost functions and present the gradient algorithm for estimating directly the time delay and the parameters....

An identification method is described for Wiener time delay systems. It consists in identifying in two-stage the parameters and the time delay: the estimation of the parameters is solved by applying a gradient algorithm and the time delay is identified by using a Variable Regression Estimation technique. Simulation results are presented to illustra...

This chapter addresses the problem of clustering based procedure for the identification of PieceWise Auto-Regressive eXogenous (PWARX) models. In order to overcome the main drawbacks of the existing methods such as their sensitivity to poor initializations and the existence of outliers, we propose the use of the Chiu’s clustering algorithm and the...

In this paper, we address the problem of identifying a semi-batch olive oil esterification reactor. In fact, this reactor can be considered as a PieceWise AutoRegressive eXogenous (PWARX) system. The Chiu’s clustering procedure for the identification of PWARX systems is then applied. It consists in estimating both the parameter vector of each submo...

In this paper, we address the problem of identifying a semi-batch olive oil esterification reactor. In fact, this reactor can be considered as a PieceWise AutoRegressive eXogenous (PWARX) system. The Chiu's clustering procedure for the identification of PWARX systems is then applied. It consists in estimating both the parameter vector of each submo...

In this paper, we design a finite-time H∞ observer. The system under consideration is a linear descriptor system subject to time-varying norm bounded disturbances. The aim of this paper is focused on the design of a state observer which ensures that the estimation error is finite-time bounded and minimizes the effect of the disturbances. A non bias...