Showing papers by "Mohamed Tadjine published in 2016"

Adaptive sensor-fault tolerant control for a class of MIMO uncertain nonlinear systems: Adaptive nonlinear filter-based dynamic surface control

Abstract: This paper presents an adaptive fault tolerant control (FTC) scheme for a class of multiple-input multiple-output (MIMO) nonlinear systems against sensor faults, modeling errors and external disturbances. Four kinds of sensor faults including bias, drift, loss of accuracy and loss of effectiveness can be tolerated by the proposed FTC system. Within this scheme, dynamic surface control (DSC) technique, robust adaptation laws and adaptive nonlinear filters are combined for designing an adaptive dynamic surface control (ADSC)-based FTC system in order to compensate for the effects of sensor faults and system uncertainties (including external disturbances, modeling errors and unexpected nonlinear functions caused by sensor faults). Lyapunov approach is used to prove that all the signals in the closed-loop system are bounded and the tracking-errors can be forced to converge into a small neighborhood of zero. The feasibility and the effectiveness of the proposed FTC controller are demonstrated through two simulation examples.

Adaptive observer-based fault estimation for a class of Lipschitz nonlinear systems

Abstract: Fault input channels represent a major challenge for observer design for fault estimation. Most works in this field assume that faults enter in such a way that the transfer functions between these faults and a number of measured outputs are strictly positive real (SPR), that is, the observer matching condition is satisfied. This paper presents a systematic approach to adaptive observer design for joint estimation of the state and faults when the SPR requirement is not verified. The proposed method deals with a class of Lipschitz nonlinear systems subjected to piecewise constant multiplicative faults. The novelty of the proposed approach is that it uses a rank condition similar to the observer matching condition to construct the adaptation law used to obtain fault estimates. The problem of finding the adaptive observer matrices is formulated as a Linear Matrix Inequality (LMI) optimization problem. The proposed scheme is tested on the nonlinear model of a single link flexible joint robot system.

New approach for the modeling of induction machines operating under unbalanced power system

Abstract: Summary In this paper, a new analytical method for the modeling of the star connected induction motors operating under unbalanced power supply is developed using coupled circuits theory. This method takes into account the increase of the common point voltage during unbalanced supply conditions. The equations, which describe the state model as well as the calculation of machine inductances, are presented. The calculation of inductances is based on the magnetomotive force distribution through the machine air-gap. The advantages of the proposed method are multiple. The space and time harmonics can be taken into account. It can also be extended for the analysis of faulty induction machines. Magnetic saturation, skin effect, skewed rotor, and slotting effects can be integrated in the calculation of the machine inductances by introducing some techniques to the basic coupled circuit theory. This method reduces strongly the time simulation because of the simple numerical representation of the inductances and their derivatives. The obtained results show good agreement with other results, which have been obtained using finite elements method and symmetrical components approach. The particularity of this work is that it takes in consideration the increase of the common point voltage during unbalanced supply conditions. Simulation results show the consistency and the applicability of the proposed method for the modeling of induction motors operating under unbalanced power system. Copyright © 2016 John Wiley & Sons, Ltd.

Improvement of sensorless vector controlled induction motor drives using a new algorithm for the rotor resistance adaptation

Abstract: This paper describes the design of a new algorithm for the rotor resistance adaptation. The obtained adaptive observer is used for the improvement of the vector control of induction motor (IM) drives. The adaptive observer detects the rotor speed and flux components in the stationary reference frame using the stator voltages and currents. Stability analysis based on Lyapunov theory is performed in order to guarantee the closed loop stability. In addition, the estimated rotor resistance is used for correction of the controllers and the rotor time constant which is used in the calculation of the stator pulsation. Simulation tests under disturbances are provided to evaluate the consistency and the effectiveness of the proposed control technique in terms of robustness and dynamic performances.

Online monitoring and accident diagnosis aid system for the Nur Nuclear Research Reactor

Abstract: This paper deals with the design of a computerized monitoring and diagnosis aid system (CMDAS) for the Nur Nuclear Research Reactor based on real-time plant-specic safety parameters. The CMDAS carries out early detection and identication of accidents that might affect this reactor using supervised neural networks. The graphical programming language LabVIEW is used for creating a human{operator interface, networking, embedding the diagnosis procedure, and handling and storing the data. The methodology presented in this paper can be adapted for any nuclear research reactor.

Sensor fault tolerant control of a photovoltaic DC-DC buck converter: HDS approach

Abstract: The problem of sensor fault tolerant control of a DC-DC buck converter for voltage regulation of a photovoltaic (PV) system is considered in this paper. By the mean of hybrid dynamical system approach (HDS); a new hybrid PV model is proposed in order to deal with the non-linearity of the PV mathematical model, the stability of the hybrid observer and the closed loop of the system is demonstrated by means of Lyapunov analysis. The simulation was performed using real PV array parameters that were obtained using Particle Swarm Optimization (PSO) identification algorithm.

A new sizing algorithm of renewable hybrid systems PV-diesel generator-battery: Application to the case of Djanet city of Algeria

Abstract: A method for optimal sizing of hybrid system consisting of aPhotovoltaic (PV) panel, diesel generator, Battery banks and load is considered in this paper. To this end a novel approach is proposed. More precisely a methodology for the design and simulation of the behavior of Hybrid system PV-Diesel-Battery banks to electrify an isolated rural site in southern Algeria Illizi (djanet). This methodology is based on the concept of the loss power supply probability (LPSP). Sizing and simulation are performed using MATLAB. The technoeconomic study shows the performances of the proposed approach.

A CDM-backstepping control with nonlinear observer for electrically driven robot manipulator

Abstract: This paper presents a CDM-backstepping strategy for motion control of Electrically-driven manipulator under the conditions of uncertainty and the action of external disturbance, while incorporating a nonlinear observer. Based on this model, a systematic analysis and design algorithm is developed to deal with stabilization and trajectory tracking of elbow robot, one feature of this work is employing the backstepping observer to achieve the exponential stability with position and velocity estimations. The results of computer simulations demonstrate that accurate and robust motion control can be achieved by using the proposed approach.

On The Control of Parabolic Solar Collector: The Zipper Approach

Abstract: - Creative inspirations that marked the great moments of human genius are linked to seemingly insignificant details: an Apple for Newton, a Bath for Archimedes, and many other impressive examples. In this paper, we propose a new controller design inspired from the functioning principle of "The zipper". The main motivation of this work consists in forcing the outlet temperature of a solar collector to track a desired reference. The proposed control scheme is based on the Lapunov stability analysis as well as the zipper functioning principle. Finally, numerical simulations are done with real system parameters for showing the effectiveness of the proposed controller.

The zipper: A lyapunov control design for parabolic solar collector

Abstract: One of the most challenging control problems in parabolic solar collector consists in forcing the outlet oil temperature to track a desired reference, due to the complexity of the PDE model governing the temperature evolution in this latter. In this paper, we propose an efficient and elegant method inspired from the functioning principle of the zipper as well as the lyapunov stability theory to reach this aim. To show the efficiency of the proposed method, numerical simulations are done using real system parameters, the obtained results are very satisfactory.