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Design of a Voltage Controller for a DC-DC Buck Converter Using Fractional-Order Terminal Sliding Mode Control Strategy

B. Babes, A. Boutaghane, N.Hamouda, M. MEZAACHE  (2019)
Article de conférence

This paper suggests a fractional-order terminal sliding mode control (FO-TSMC) method for the output voltage regulation of a DC-DC buck converter influenced by disturbances, such as the variations of load resistance and input voltage. A this kind of a new fractional-order (FO) dynamic sliding surface is designed to avoid the drawback on integer-order (IO) terminal sliding mode control (IO-TSMC) method and guarantee the converter reach steady-state quickly without chattering even if it undergoes arbitrary random disturbances. The proposed FO-TSMC controller’s performance is compared against to both IO-TSMC and traditional SMC control approaches. Computer simulation results display that the novel FO-TSMC approach results in evenhanded output voltage regulation performance under widely input voltage variations and load changes. Voir les détails

Mots clés : Sliding Mode Control (SMC), terminal sliding mode control (TSMC), fractional-order (FO), DC-DC buck converter

A Robust Adaptive Fuzzy Fast Terminal Synergetic Voltage Control Scheme for DC/DC Buck Converter

B. Babes, A. Boutaghnae, N. Hamouda, M. MEZAACHE, S. Kahla  (2019)
Article de conférence

In this paper, an adaptive fuzzy fast terminal synergetic voltage control scheme for DC/DC buck converter is proposed based on recently developed synergetic theory and a terminal attractor method. The advantages of presented synergetic control include the characteristics of finite time convergence, insensitive to parameters variation and chattering free phenomena. Rendering the design more robust, fuzzy logic systems are used to approximate the unknown parameters in the proposed controller without calling upon usual model linearization and simplifications. Taking the DC/DC buck converter in continuous conduction mode as an example, the algorithm of proposed synergetic control is analyzed in detail. All the simulation results demonstrate the effectiveness and the high dynamic capability of the proposed AF-FTSC control technique over the FTSC strategy. Voir les détails

Mots clés : synergetic control, fuzzy logic system, terminal technique, finite time convergence, DC/DC buck converter

Software Features Extraction From Object-Oriented Source Code Using an Overlapping Clustering Approach

Imad Eddine ARAAR, Hassina SERIDI  (2016)
Publication

For many decades, numerous organizations have launched software reuse initiatives to improve their productivity. Software product lines (SPL) addressed this problem by organizing software development around a set of features that are shared by a set of products. In order to exploit existing software products for building a new SPL, features composing each of the used products must be specified in the first place. In this paper we analyze the effectiveness of overlapping clustering based technique to mine functional features from object-oriented (OO) source code of existing systems. The evaluation of the proposed approach using two different Java open-source applications, i.e. “Mobile media” and “Drawing Shapes”, has revealed encouraging results. Voir les détails

Mots clés : feature model, software product line, overlapping clustering, reverse engineering, program analysis

Etude et caractérisation de l’interface lors du soudage de matériauxmétalliques non ferreux :

MEBTOUCHE Ahmed (En préparation)
Thèse de doctorat

Le procédé, appelé soudage par friction, se présente comme un bon choixpour le soudage des matériaux métalliques ferreux non ferreux, parfois nonsoudables pour certaines séries d’alliage d’aluminium.Ce procédé s’effectue à l’état pâteux, sans atteindre la fusion, et il permet desouder des dissemblables et d’éviter les inconvénients inhérents aux procédésde soudage conventionnels.Le choix, des paramètres du mode opératoire, ainsi que l’originalité dans cetravail restent déterminants pour apporter une innovanteCe travail porte sur la caractérisation non destructive et destructive del’interface des soudures obtenues, représente notre zone d’intérêt. Voir les détails

Mots clés : friction

CARACTERISATION DE LA GROSSEUR DES GRAINS DANSLES MATERIAUX SOLIDES PAR ONDES ACOUSTIQUES

MEBTOUCHE Ahmed (2013)
Mémoire de magister

Les ultrasons ont prouvé leur efficacité dans le domaine de lacaractérisation non destructive des matériaux. Leur application se diversifie dejour en jour. Outre leur application dans le domaine industriel. Les ultrasons offrentune fiabilité certaine dans la caractérisation non destructive des propriétésphysiques, mécaniques et chimiques Voir les détails

Mots clés : taille de graine

Utilisation des Méthodes Variationnelles et des Équations d’Évolution en Traitement d’Images

boutiche yamina (2018)
Thèse de doctorat

Le travail mené dans le cadre de cette thèse porte, essentiellement, sur la segmentation etla restauration des images par les techniques basées sur l’évolution de courbes, les equations aux dérivées partielles (EDP) et le calcul variationnel. Notre intérêt s’est porté sur la représentation implicite des courbes via les ensembles de niveaux. Plusieurs avantages découlent de l’utilisation d’une telle représentation, elle présente moins de contraintes sur la géométrie des objets à segmenter (peuvent être irréguliers c.-à-d. avec de fortes courbures). De plus, elle permet un changement automatique de la topologie en cours d’évolution.Pour amorcer ce travail, nous nous sommes penchés, en premier, sur la famille des contoursactifs paramétriques. Par la suite, nous avons étudié les contours actifs implicites basés contour et ceux basés région. Une attention particulière a été accordée aux approches basées région vu leurs multiples avantages comparé à la famille des approches basées contour. De ce fait, nous avons pu mettre en évidence les points forts et faibles des trois grandes classes des contours actifs basé région, à savoir les approches globales, locales et hybrides.Ce travail nous a mené à proposer une fonctionnelle d’énergie régissant l’évolution ducontour, combinant des statistiques locales (moyennes et variances) et des statistiques globales (moyennes), avec une hybridation à poids dynamique de ces deux termes. Aussi, la rapidité de la convergence a été significativement améliorée en nous inspirant de l’algorithme par balayage (sweeping) pour proposer un algorithme rapide d’optimisation de la fonctionnelle. Ce dernier permet de calculer l’optimum de la fonctionnelle sans avoir à passer par l’équation d’Euler-Lagrange. Ces deux points constituent l’essentiel de notre contribution dans cette thèse. Enfin, pour valider nos résultats, une étude comparative et une évaluation quantitative ont été mises en oeuvre entre le modèle proposé et les modèles les plus en vue de la familledes contours actifs basés région. Voir les détails

Mots clés : Segmentation d’images, Restauration d’images, regularisation, Approches variationnelles, Ensembles de niveaux, Statistiques locales et globales

Correlation Between the Pitting Potential Evolution and σσ Phase Precipitation Kinetics in the 2205 Duplex Stainless Steel

Mustapha DJAMA, Djaffar Saidi, Abdelaziz Kadri, Nabil KHERROUBA, Brahim MEHDI, Stéphane Mathieu, Thierry Schweitzer, IDIR Brahim  (2018)
Publication

The aim of this work is to correlate the pitting potential (Epit) evolution with the kinetics ofrphaseprecipitation in the 2205 duplex stainless steel aged at 850°C after solution treatment at 1150°C. Thepotentiodynamic polarization curves indicate a reduction of the pitting corrosion resistance with the agingtime, which is revealed by a decrease in theEpitvalues from 0.65 to 0.40 VSCE. Thus,Epitvalues are used todetermine the kinetics parameters of therphase precipitation. The experimental transformed fractionagrees well with the one calculated by using the modified Kolmogorov–Johnson–Mehl–Avrami equationwith an impingement parameterc= 0.6. Voir les détails

Mots clés : kinetic, KJMA, Pitting corrosion, otentiodynamic polarization, r phase precipitation

Isothermal and non-isothermal precipitation kinetics in Al–Mg–Si-(Ag) alloy

Oussama.Djema, Mabrouk.Bouabdallah, Riad.Badji, Amr.Saadi, Nabil.Kherrouba, Amane.Sahli  (2019)
Publication

In the present work, isothermal and non-isothermal precipitation kinetics in a 6063 aluminium alloy containing a small silver (Ag) addition have been investigated using Vickers microhardness and Differential Scanning Calorimetry (DSC) measurements respectively. Isothermal kinetics analysis showed that β'' phase precipitation obeyed the Johnson-Mehl-Avrami (JMA) model. The DSC analysis revealed that Ag addition modified the precipitation sequence in the investigated 6063 aluminium alloy through the formation of an additional metastable pre-β'' phase. An approach based on the additivity concept has been applied to the heating DSC diagrams to investigate the β'' phase precipitation. The obtained Avrami exponent values from this approach led to suggest that the β'' phase precipitation proceeded through two processes during continuous heating. The Avrami exponent value obtained at the final stage of the transformation was consistent with that obtained from the isothermal analysis, whereas the corresponding activation energy was higher than the one calculated from the isothermal analysis and Kissinger's method. It was also established that the precipitation kinetics of the β'' phase was enhanced by the formation of the precursor phase pre-β''. Voir les détails

Mots clés : 6063 aluminium alloy, Ag addition, Precipitation kinetics, JMA model, Additivity concept

Effect of solution treatment on the microstructure, micromechanical properties, and kinetic parameters of the β → α phase transformation during continuous cooling of Ti-6Al-4V titanium alloy

Nabil KHERROUBA, Denis CARRON, Mabrouk BOUABDALLAH, Riad BADJI  (2019)
Publication

The aim of this study is to examine the effect of solution treatment temperature (STT) on the microstructure, the micromechanical properties, and the kinetic parameters of the β → α phase transformation during continuous cooling of the dual phase titanium alloy Ti-6Al-4V. Increasing the STT from 1050 °C to 1200 °C delays the formation of the α phase during cooling and increases the value of its activation energy. The microstructural analysis reveals the emergence of αW platelets from protuberances on the αGB / αW interface. The investigation of the morphology of the αW platelets reveals the presence of ledges on their longest side showing a sharp extremity. The micromechanical properties determined by nanoindentation and microhardness tests are almost insensitive to the cooling rate but are strongly affected by the STT; the higher the STT, the lower the overall microhardness of the Ti-6Al-4V alloy. In addition, the STT affects the microhardness and the Young’s modulus of both α and β phases differently; when the STT increases, the microhardness and the Young’s modulus of the α phase decrease whereas those of the β phase increase. Voir les détails

Mots clés : Ti-6Al-4V, solution treatment, ledge mechanism, interface instability, Nanoindentation, partitioning

Structural, Electronic and Mechanical Properties of C14-Mg 2 RE(RE=Eu, Er, Tm, Yb and Lu) Laves Phases: A DFT Study

A. Zahague, B. Lagoun, A. Legris, R. Besson, L. Rabahi, D. Bradai  (2019)
Publication

The Pseudo-Potential Density Functional Theory (PP-DFT) method is applied to investigatethe structural, electronic and mechanical properties of C14-Mg 2 RE Laves phases, with RE being Eu,Er, Tm, Yb and Lu. The predicted cell parameter and c/a ratio of each compound are in good agreement with experimental and theoretical results. Moreover, the studied alloys exhibit a metalliccharacter, which is attributed to the presence of Mg atoms in the C14 Laves phase. Also, theformation of C14-Mg 2 RE is found to be controlled by the hybridisation between Mg p states and RE-d and f states. From a mechanical property analysis, the studied alloys are found to be mechanicallystable. The Mg 2 Lu compound exhibits higher ductility, while Mg 2 Er exhibits the smallest one.Finally, Mg 2 Yb is found to be more anisotropic than other phases. Voir les détails

Mots clés : A DFT calculations, B Magnesium based Laves phases, C Density Functional Theory (DFT), D Mechanical properties, E Electronic properties