Download or read book Commande Robuste Et Optimale Via Les Techniques Par Intervalles Pour Le Contr le de Microsyst mes written by Mounir Hammouche and published by . This book was released on 2018 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric actuators are widely used at micro/nanoscale because of their simpleconfiguration, high resolution (sub-nanometric), high speed (large bandwidth upto 1kHz), and high force density. However, they are characterized by some nonlinearitiessuch as hysteresis, internal friction and creep,...etc. These characteristicsconsiderably impact the dynamics of the piezoactuators which makes the controlof these systems not a trivial task. Various robust controllers have been developedto control piezoelectric actuators. These include high gain feedback approach, H1approach, disturbance observer based control approach,...etc. Those techniquesdemonstrated a significant improvement of the control performance, but they oftenderive controllers with high-order which are difficult for implementation. Tobypass this limitation, we focus on the thesis on combining interval analysis withclassical controller design techniques to obtain a low order controllers. The mainadvantage of intervals is that they permit to model parametric uncertainties easilyby bounding them. Furthermore, the process of modeling the system uncertaintiesby intervals makes the synthesis of robust controller with low order relatively easy.The state of the art on the use of interval techniques to design and derive robustcontrollers for uncertain system can be divided into two categories: intervaltransfer functions based approaches and interval state-space representation basedapproaches. Interval transfer functions based designs have been widely used tomodel and to control SISO (Single Input single Output) systems subjected to uncertainties.These approaches make the synthesis of robust controllers for suchsystems easy with providing good performance. However, the current work thatuse interval transfer functions are limited to systems in SISO case. In the otherside, the state-space based approaches have been shown to be well adapted tosynthesis robust controllers for multivariable systems. Nevertheless, the excitingworks are limited to systems with state and input matrices of special structures.Furthermore, they address only the degree of stability of the closed-loop systemwithout discussing performance specification. In order to make the design of robustcontroller using interval state-space approach possible for any interval state-spacestructure, this thesis will explore the interval state-space control design using robustpole assignment technique. This proposed approach will guarantee the stability and the desired performance of the closed-loop system also it allows to obtaina low order controller.For this matter, an algorithm based on Set Inversion Via Interval Analysis(SIVIA) combined with interval eigenvalues computation is proposed to seek for aset of robust gains. This recursive SIVIA-based algorithm allows to approximatewith subpaving the set solutions [K] that satisfy the inclusion of the eigenvaluesof the closed-loop system in a desired region in the complex plan. Furthermore,simple algorithms are proposed to find the optimal feedback gains among the rangeof robust gains [K] as well as the range of the gains that satisfy input constraints,all with the help of interval analysis. Finally, in order to improve the controllerperformance, we were directed our attention to nonlinear control approaches andespecially interval sliding mode control (ISMC) design using interval observers.The effectiveness of the proposed approaches are tested by a real experimentationon several platforms developed in our laboratory to achieve robust performance.
Download or read book Techniques de commande robuste written by Christelle Manceaux-Cumer and published by . This book was released on 1998 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse concerne l'analyse et la synthèse de commandes, capables de stabiliser des systèmes linéaires en dépit d'incertitudes fréquentielles et paramétriques. Les travaux sont essentiellement axés sur la mise en œuvre pratique des méthodes de commande robuste. Mais, la prise en compte de la nature et de la structure de l'incertitude ainsi que le niveau de suffisance du critère de stabilité choisi rendent ce problème difficile à résoudre. Les méthodes couramment utilisées sont récapitulées mais ne répondent que partiellement au problème d'analyse. En particulier, les critères de stabilité mis sous forme de tests fréquentiels souffrent de l'échantillonnage fréquentiel et ne peuvent qu'induire des erreurs lors de la synthèse (μ-analyse et μ-synthèse). L'obtention de critères de stabilité pratiques pour la synthèse a donc orienté les travaux dans deux directions complémentaires. Le premier axe de recherche élabore des algorithmes fondés sur la théorie des multiplicateurs pour traiter des problèmes de type μ-synthèse (ou synthèse H2 robuste) dans lesquels les incertitudes peuvent être mixtes. Là encore, nous utilisons une heuristique classique qui alterne entre analyse, à correcteur fixé, et synthèse, à multiplicateur fixé mais qui présente l'avantage d'éviter l'échantillonnage en fréquences. Au préalable, les multiplicateurs sont choisis dans une base soit polynômiale soit rationnelle. Ces approches se formulent par des problèmes d'optimisation convexe, de type LMI. Le scond axe de recherche utilise une technqiue hybride identification / commande pour le calcul des marges paramétriques d'un système commandé (PRABI), fondée sur la qualité d'identification paramétrique. Cette technique est exploitée pour l'obtention d'un nouvel algotithme de désensibilisation. On robustifie itérativement un compensateur à structure donnée, tout en assurant un compromis performance / robustesse paramétrique. Cela nous amène à travailler successivement dans l'espace des paramètres définissant le correcteur, puis dans l'espace des paramètres inhérents au modèle. En fin, on propose une généralisation de la méthode d'analyse PRABI, nécessitant le calcul d'un correcteur LQG équivalent. Toutes ces techniques sont validées sur des cas tests et des problèmes réalistes de l'aéronautique (missile, satellite de télécommunication).
Download or read book Approche LMI de la commande robuste multicrit re written by Stéphane Dussy and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: En automatique, l'asservissement d'un système peut se définir comme la recherche d'une loi de commande devant satisfaire un ensemble de spécifications parfois concurrentes. Ces dernières incluent entre autres des critères de stabilité, de temps de réponse, de rejet de perturbations, de passivité, de bornes sur la commande, de saturations de certaines sorties ou de robustesse par rapport à des incertitudes paramétriques ou de modélisation ... Remplir un tel cahier des charges pour un système linéaire est déjà un problème difficile en soi. La motivation principale de la thèse est de proposer une méthodologie de synthèse de cor recteur qui garantisse simultanément ces spécifications pour une large classe de systèmes non-linéaires incertains. Les problèmes numériques, dits de précision finie, rencontrés lors de l'implémentation du correcteur dans un système réel sont aussi abordés. Les techniques proposées de recherche de loi de commande robuste reposent sur la traduction des contraintes sous la forme de problèmes d'optimisation convexe. Une formulation des conditions dite par Inégalités Matricielles Linéaires (LMI) permet alors, grâce à de récentes avancées dans le domaine de l'optimisation par points intérieurs, de synthétiser numérique ment une loi de commande. Cette approche représente un bon compromis entre calculabilité et complexité des conditions de synthèse. Des algorithmes sont alors définis, adaptés à la commande de différents types de systèmes, et des exemples d'application sont traités. Un logiciel, sous la forme d'une boîte à outils Matlab, a été développé pour permettre à un ingénieur automaticien d'utiliser les techniques présentées dans la thèse de manière transparente et sans connaissance pré-requise en optimisation convexe.
Download or read book X OPEN Portability Guide Programming languages written by and published by . This book was released on 1987 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Dominated Flows written by Denis L. Blackmore and published by World Scientific. This book was released on 2005 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: Honoring the contributions of one of the field's leading experts, Lu Ting, this indispensable volume contains important new results at the cutting edge of research. A wide variety of significant new analytical and numerical results in critical areas are presented, including point vortex dynamics, superconductor vortices, cavity flows, vortex breakdown, shock/vortex interaction, wake flows, magneto-hydrodynamics, rotary wake flows, and hypersonic vortex phenomena.The book will be invaluable for those interested in the state of the art of vortex dominated flows, both from a theoretical and applied perspective.Professor Lu Ting and Joe Keller have worked together for over 40 years. In their first joint work entitled ?Periodic vibrations of systems governed by nonlinear partial differential equations?, perturbation analysis and bifurcation theory were used to determine the frequencies and modes of vibration of various physical systems. The novelty was the application to partial differential equations of methods which, previously, had been used almost exclusively on ordinary differential equations. Professsor Lu Ting is an expert in both fluid dynamics and the use of matched asymptotic expansions. His physical insight into fluid flows has led the way to finding the appropriate mathematical simplications used in the solutions to many difficult flow problems.
Download or read book Instabilities in Multiphase Flows written by A. Berlemont and published by . This book was released on 2014-01-15 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parallel Computing written by Barbara Chapman and published by IOS Press. This book was released on 2010 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: From Multicores and GPUs to Petascale. Parallel computing technologies have brought dramatic changes to mainstream computing the majority of todays PCs, laptops and even notebooks incorporate multiprocessor chips with up to four processors. Standard components are increasingly combined with GPUs Graphics Processing Unit, originally designed for high-speed graphics processing, and FPGAs Free Programmable Gate Array to build parallel computers with a wide spectrum of high-speed processing functions. The scale of this powerful hardware is limited only by factors such as energy consumption and thermal control. However, in addition to"
Download or read book Modelling Fluid Flow written by János Vad and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling Fluid Flow presents invited lectures, workshop summaries and a selection of papers from a recent international conference CMFF '03 on fluid technology. The lectures follow the current evolution and the newest challenges of the computational methods and measuring techniques related to fluid flow. The workshop summaries reflect the recent trends, open questions and unsolved problems in the mutually inspiring fields of experimental and computational fluid mechanics. The papers cover a wide range of fluids engineering, including reactive flow, chemical and process engineering, environmental fluid dynamics, turbulence modelling, numerical methods, and fluid machinery.
Download or read book Parallel Computational Fluid Dynamics written by Kenli Li and published by Springer. This book was released on 2014-03-08 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 25th International Conference on Parallel Computational Fluid Dynamics, ParCFD 2013, held in Changsha, China, in May 2013. The 35 revised full papers presented were carefully reviewed and selected from more than 240 submissions. The papers address issues such as parallel algorithms, developments in software tools and environments, unstructured adaptive mesh applications, industrial applications, atmospheric and oceanic global simulation, interdisciplinary applications and evaluation of computer architectures and software environments.
