Tarek Ahmed‐Ali

Normandie Université

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Françoise Lamnabhi‐Lagarrigue

Supélec

F. Giri

Université de Caen Normandie

Mohamed Benbouzid

Université de Bretagne Occidentale

Godpromesse Kenné

Université de Dschang

Amir Arzandé

CentraleSupélec

Brice Beltran

Université de Bretagne Occidentale

Laurent Burlion

Rutgers, The State University of New Jersey

Iasson Karafyllis

National Technical University of Athens

V. Van Assche

Laboratoire de Physique Corpusculaire de Caen

Estelle Cherrier

GREYC

Cooperative Institutions

Centre National de la Recherche Scientifique

GREYC

Université de Caen Normandie

Normandie Université

École Nationale Supérieure d'Ingénieurs de Caen

Laboratoire de Physique Corpusculaire de Caen

Supélec

Mohammed V University

Université de Bretagne Occidentale

École nationale supérieure de techniques avancées Bretagne

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Robust backstepping for the Euler approximate model of sampled-data strict-feedback systems

Automatica (2009)

Romain Postoyan Tarek Ahmed‐Ali Françoise Lamnabhi‐Lagarrigue

10.1016/j.automatica.2009.05.001

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Citations (41)

A Note on Sampled-Data Observers

arXiv (Cornell University) (2019)

Iasson Karafyllis Tarek Ahmed‐Ali F. Giri

We present a new approach for deriving sampled-data observers from continuous-time observers that feature an Input-to-Output Stability property with respect to the output measurement noise and exponential convergence in the noiseless case. The design approach applies to a wide class of systems and yields sampled-data observers that inherit all performance characteristics of the underlying continuous-time observers. The main component of the proposed sampled-data observer is a novel output predictor that encompasses both inter-sample predictors and ZOH-predictors.

Observer (physics)

Feature (linguistics)

Component (thermodynamics)

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Sampled-Data Based State and Parameter Estimation for State-Affine Systems with Uncertain Output Equation

IFAC-PapersOnLine (2018)

Tarek Ahmed‐Ali Koen Tiels Maarten Schoukens F. Giri

The problem of sampled-data observer design is addressed for a class of state- and parameter-affine nonlinear systems. The main novelty in this class lies in the fact that the unknown parameters enter the output equation and the associated regressor is nonlinear in the output. Wiener systems belong to this class. The difficulty with this class of systems comes from the fact that output measurements are only available at sampling times causing the loss of the parameter-affine nature of the model (except at the sampling instants). This makes existing adaptive observers inapplicable to this class of systems. In this paper, a new sampled-data adaptive observer is designed for these systems and shown to be exponentially convergent under specific persistent excitation (PE) conditions that ensure system observability and identifiability. The new observer involves an inter-sample output predictor that is different from those in existing observers and features continuous trajectories of the state and parameter estimates.

Identifiability

Observability

Observer (physics)

10.1016/j.ifacol.2018.09.193

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Citations (2)

Time-varying parameter identification of a class of nonlinear systems with application to online rotor resistance estimation on induction motors

HAL (Le Centre pour la Communication Scientifique Directe) (2006)

Godpromesse Kenné Tarek Ahmed‐Ali Françoise Lamnabhi‐Lagarrigue Amir Arzandé

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High Gain Observer Design for Some Networked Control Systems

IEEE Transactions on Automatic Control (2011)

Tarek Ahmed‐Ali Françoise Lamnabhi‐Lagarrigue

New results on high gain observer design for networked control systems via an emulation-like approach are presented. By using a general framework and a Lyapunov approach, we derive some explicit conditions on the maximum allowable transmission interval that ensure an exponential convergence of the observation error for a large class of network protocols.

Observer (physics)

Networked control system

10.1109/tac.2011.2168049

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Citations (48)

Power Sharing and Parallel Inverters Control in Islanded Microgrids

Leila Ammeh El Fadil Hassan F. Giri Tarek Ahmed‐Ali

This paper deals with the control of parallel voltage source inverters (VSI) in microgrid islanded mode while sharing the active and reactive power required by the load. Firstly, an islanded microgrid composed of n distributed energy resources (DER) connected to each other through VSI and nonlinear load is modelled. Thereafter, a master slave based control strategy is proposed. One of the VSI is designated as a master and it is responsible for controlling the microgrid AC bus voltage and responsible, also, for setting the reference current to be supplied by the slave VSI. In the other hand, the slaves are responsible for controlling their output currents following the references received from the master VSI; in that way, the active and reactive power are shared among all the DER proportionally to their rated generated power. The control of the VSI voltage and current is ensured applying the backstepping technique. Using Lyapunov theory, the closed loop system is globally asymptotically stable. From the simulation case study, the proposed control strategy ensures the voltage control of the n parallel VSI as well as the power sharing between the n DER without being overloaded.

Microgrid

Master/slave

Power sharing

10.1109/isaect53699.2021.9668505

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Sampled-data observer for supercapacitor parameters estimation under NEDC cycles

E. Magarotto Philippe Dorléans Tarek Ahmed‐Ali

Observer (physics)

Driving cycle

Source

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Sampled-data based observer design for nonlinear systems with output distributed delay

International Journal of Control (2019)

Leila Ammeh F. Giri Tarek Ahmed‐Ali Hassan El Fadil

Existing observers that accommodate distributed-delays are mainly designed for linear systems with continuous-time output measurements. In this paper, we seek sampled-measurements-based observers for nonlinear systems with strict-feedback globally Lipschitz dynamics and distributed-delay. Invoking the high-gain principle, we design two observers operating with sampled output measurements. In both, the delay effect is compensated for by using distributed output-predictors. The first observer involves an intersample predictor and its exponential convergence is established using a quadratic Lyapunov function. The second observer involves a zero-order-hold predictor and the exponential convergence is proved using a Lyapunov–Krasovskii functional. To the author's knowledge, it is the first time that an exponentially convergent observer is developed for nonlinear systems with output distributed-delay and sampled output measurements.

Observer (physics)

10.1080/00207179.2019.1680871

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Citations (7)

Time-Varying Parameter Identification of a Class of Nonlinear Systems With Application to Online Rotor Resistance Estimation of Induction Motors

Godpromesse Kenné Tarek Ahmed‐Ali Françoise Lamnabhi‐Lagarrigue Amir Arzandé

In this paper, algorithm for time-varying parameter estimation of a large class of nonlinear systems is presented. This method is based on the variable structure theories. The algorithm developed is potentially useful for adjusting the controller parameters of variable speed drive and can be used for both constant and time-varying parameter estimation. The real-time estimation of the rotor resistance of an induction motor based on this approach, show rapidly converging of estimates in spite of the measurement noise, discretization effects, parameter uncertainties (e.g. inaccuracies on motor inductance values) and modeling inaccuracies. The robustness analysis for induction motor application also revealed that the proposed scheme is insensitive to the stator resistance variations. The merits of the proposed algorithm in the case of time-varying parameter are demonstrated via experimental results in various operating conditions of the induction motor

Robustness

10.1109/isie.2006.295610

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Citations (13)

Observers Design for Systems with Sampled Measurements, Application to AC Motors

V. Van Assche Philippe Dorléans J.-F. Massieu Tarek Ahmed‐Ali

This chapter presents two observer designs for nonlinear systems with sampled measurements and their application to an induction motor. The first design is a direct adaptation of the continuous high gain observer. The output is sampled and its value is held, thus the correction term in the observer equation is constant between sampling instants. The second observer scheme includes a predictor based on the work by Karafyllis and Kravaris to estimate the output between two sampling instants. At each sampling instant, the predictor is reset to the actual value of the output. The output estimation is fed to the correction term of the observer. The Matlab/Simulink is used to test the implementation of those observers on a simulation model of the induction machine.

Observer (physics)

Reset (finance)

Constant (computer programming)

10.1002/9781118574263.ch6

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