Documents disponibles écrits par cet auteur

Boundary observer for output-feedback stabilization of thermal-fluid convection loop / Vazquez, Rafael in IEEE Transactions on control systems technology, Vol. 18 N° 4 (Juillet 2010) 

Public ISBD [article]  in IEEE Transactions on control systems technology > Vol. 18 N° 4 (Juillet 2010) . - pp. 789-797 Titre : Boundary observer for output-feedback stabilization of thermal-fluid convection loop Type de document : texte imprimé Auteurs : Vazquez, Rafael, Auteur ; Krstic, Miroslav, Auteur Année de publication : 2011 Article en page(s) : pp. 789-797 Note générale : Génie Aérospatial Langues : Anglais (eng) Mots-clés : Backstepping  Boundary  control  Distributed  parameter  systems  Flow  control  Partial  differential  equations  (PDEs)  Observers  Singularly  systems  Stabilization Index. décimale : 629.1 Résumé : In this paper, we consider a 2-D model of thermal fluid convection that exhibits the prototypical Rayleigh-Bernard convective instability. The fluid is enclosed between two cylinders, heated from above, and cooled from below, which makes its motion unstable for a large enough Rayleigh number. We design an stabilizing output feedback boundary control law for a realistic collocated setup, with actuation and measurements located at the outer boundary. Actuation is through rotation (direct velocity actuation) and heat flux (heating or cooling) of the outer cylinder, while measurements of friction and temperature are obtained at the same boundary. Though only a linearized version of the plant is considered in the design, an extensive closed loop simulation study of the nonlinear model shows that our design works for reasonably large initial conditions. A highly accurate approximation to the control kernels and observer output injection gains is found in closed form. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5208259 [article] Boundary observer for output-feedback stabilization of thermal-fluid convection loop [texte imprimé] / Vazquez, Rafael, Auteur ; Krstic, Miroslav, Auteur . - 2011 . - pp. 789-797. Génie Aérospatial Langues : Anglais (eng) in IEEE Transactions on control systems technology > Vol. 18 N° 4 (Juillet 2010) . - pp. 789-797 Mots-clés : Backstepping  Boundary  control  Distributed  parameter  systems  Flow  control  Partial  differential  equations  (PDEs)  Observers  Singularly  systems  Stabilization Index. décimale : 629.1 Résumé : In this paper, we consider a 2-D model of thermal fluid convection that exhibits the prototypical Rayleigh-Bernard convective instability. The fluid is enclosed between two cylinders, heated from above, and cooled from below, which makes its motion unstable for a large enough Rayleigh number. We design an stabilizing output feedback boundary control law for a realistic collocated setup, with actuation and measurements located at the outer boundary. Actuation is through rotation (direct velocity actuation) and heat flux (heating or cooling) of the outer cylinder, while measurements of friction and temperature are obtained at the same boundary. Though only a linearized version of the plant is considered in the design, an extensive closed loop simulation study of the nonlinear model shows that our design works for reasonably large initial conditions. A highly accurate approximation to the control kernels and observer output injection gains is found in closed form. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5208259

A Closed-form feedback controller for stabilization of the linearized 2-D navier–stokes poiseuille system / Vazquez, Rafael in IEEE transactions on automatic control, Vol. 52 N°12 (Decembre 2007) 

Public ISBD [article]  in IEEE transactions on automatic control > Vol. 52 N°12 (Decembre 2007) . - 2298-2312 p. Titre : A Closed-form feedback controller for stabilization of the linearized 2-D navier–stokes poiseuille system Titre original : Un contrôleur de rétroaction de forme close pour la stabilisation de la 2-D linéarisé navier-charge le système de poiseuille Type de document : texte imprimé Auteurs : Vazquez, Rafael, Auteur ; Krstic, Miroslav, Auteur Article en page(s) : 2298-2312 p. Note générale : Automatique Langues : Anglais (eng) Mots-clés : Backstepping  Boundary  control  Distributed  parameter  systems  Flow  control  Lyapunov  function  Navier-Stokes  equations  Stabilization  Commande  de  frontière  Systèmes  de  paramètre  distribué  Contrôle  de  flux  Fonction  de  Lyapunov  Navier-Charge  des  équations  Stabilisation Index. décimale : 629.8 Résumé : We present a formula for a boundary control law which stabilizes the parabolic profile of an infinite channel flow, which is linearly unstable for high Reynolds numbers. Also known as the Poiseuille flow, this problem is frequently cited as a paradigm for transition to turbulence, whose stabilization for arbitrary Reynolds numbers, without using discretization, has so far been an open problem. Our result achieves exponential stability in the L2, H1, and H2 norms, for the linearized Navier-Stokes equations. Explicit solutions are obtained for the closed loop system. This is the first time explicit formulae are produced for solutions of the linearized Navier-Stokes equations in a channel flow, with feedback in the boundary conditions used to make this possible. The result is presented for the 2D case for clarity of exposition. An extension to 3D is available and will be presented in a future publication. Nous présentons une formule pour une loi de commande de frontière qui stabilise le profil parabolique d'un écoulement de canalisé infini, qui est linéairement instable pour des nombres de Reynolds élevés. Également connu comme écoulement de Poiseuille, ce problème est fréquemment cité comme paradigme pour la transition à la turbulence, dont la stabilisation pour des nombres de Reynolds arbitraires, sans employer la discrétisation, a jusqu'ici été un problème non résolu. Notre résultat réalise la stabilité exponentielle dans les normes L2, H1, et H2, parce que linéarisé Navier-Charge des équations. Des solutions explicites sont obtenues pour le système à boucle fermée. C'est la première fois que des formules explicites sont produites pour des solutions de linéarisées Navier-Charge des équations dans un écoulement de canalisé, avec la rétroaction en conditions de frontière employés pour rendre ceci possible. Le résultat est présenté pour le 2D point de droit pour la clarté de l'exposition. Une prolongation à 3D est disponible et sera présentée dans une future publication. DEWEY : 629.8 ISSN : 0018-9286 RAMEAU : Liapounov, Fonctions de En ligne : rvazquez1@us.es, krstic@ucsd.edu [article] A Closed-form feedback controller for stabilization of the linearized 2-D navier–stokes poiseuille system = Un contrôleur de rétroaction de forme close pour la stabilisation de la 2-D linéarisé navier-charge le système de poiseuille [texte imprimé] / Vazquez, Rafael, Auteur ; Krstic, Miroslav, Auteur . - 2298-2312 p. Automatique Langues : Anglais (eng) in IEEE transactions on automatic control > Vol. 52 N°12 (Decembre 2007) . - 2298-2312 p. Mots-clés : Backstepping  Boundary  control  Distributed  parameter  systems  Flow  control  Lyapunov  function  Navier-Stokes  equations  Stabilization  Commande  de  frontière  Systèmes  de  paramètre  distribué  Contrôle  de  flux  Fonction  de  Lyapunov  Navier-Charge  des  équations  Stabilisation Index. décimale : 629.8 Résumé : We present a formula for a boundary control law which stabilizes the parabolic profile of an infinite channel flow, which is linearly unstable for high Reynolds numbers. Also known as the Poiseuille flow, this problem is frequently cited as a paradigm for transition to turbulence, whose stabilization for arbitrary Reynolds numbers, without using discretization, has so far been an open problem. Our result achieves exponential stability in the L2, H1, and H2 norms, for the linearized Navier-Stokes equations. Explicit solutions are obtained for the closed loop system. This is the first time explicit formulae are produced for solutions of the linearized Navier-Stokes equations in a channel flow, with feedback in the boundary conditions used to make this possible. The result is presented for the 2D case for clarity of exposition. An extension to 3D is available and will be presented in a future publication. Nous présentons une formule pour une loi de commande de frontière qui stabilise le profil parabolique d'un écoulement de canalisé infini, qui est linéairement instable pour des nombres de Reynolds élevés. Également connu comme écoulement de Poiseuille, ce problème est fréquemment cité comme paradigme pour la transition à la turbulence, dont la stabilisation pour des nombres de Reynolds arbitraires, sans employer la discrétisation, a jusqu'ici été un problème non résolu. Notre résultat réalise la stabilité exponentielle dans les normes L2, H1, et H2, parce que linéarisé Navier-Charge des équations. Des solutions explicites sont obtenues pour le système à boucle fermée. C'est la première fois que des formules explicites sont produites pour des solutions de linéarisées Navier-Charge des équations dans un écoulement de canalisé, avec la rétroaction en conditions de frontière employés pour rendre ceci possible. Le résultat est présenté pour le 2D point de droit pour la clarté de l'exposition. Une prolongation à 3D est disponible et sera présentée dans une future publication. DEWEY : 629.8 ISSN : 0018-9286 RAMEAU : Liapounov, Fonctions de En ligne : rvazquez1@us.es, krstic@ucsd.edu

A closed-form full-state feedback controller for stabilization of 3D magnetohydrodynamic channel flow / Vazquez, Rafael in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 4 (Juillet 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 4 (Juillet 2009) . - 10 p. Titre : A closed-form full-state feedback controller for stabilization of 3D magnetohydrodynamic channel flow Type de document : texte imprimé Auteurs : Vazquez, Rafael, Auteur ; Eugenio Schuster, Auteur ; Krstic, Miroslav, Auteur Année de publication : 2009 Article en page(s) : 10 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : boundary  feedback  law;  magnetohydrodynamic  channel  flow;  Navier–Stokes  equations;  Reynolds  numbers Résumé : We present a boundary feedback law that stabilizes the velocity, pressure, and electromagnetic fields in a magnetohydrodynamic (MHD) channel flow. The MHD channel flow, also known as Hartmann flow, is a benchmark for applications such as cooling, hypersonic flight, and propulsion. It involves an electrically conducting fluid moving between parallel plates in the presence of an externally imposed transverse magnetic field. The system is described by the inductionless MHD equations, a combination of the Navier–Stokes equations and a Poisson equation for the electric potential under the MHD approximation in a low magnetic Reynolds number regime. This model is unstable for large Reynolds numbers and is stabilized by actuation of velocity and the electric potential at only one of the walls. The backstepping method for stabilization of parabolic partial differential equations (PDEs) is applied to the velocity field system written in appropriate coordinates. Control gains are computed by solving a set of linear hyperbolic PDEs. Stabilization of nondiscretized 3D MHD channel flow has so far been an open problem. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...] [article] A closed-form full-state feedback controller for stabilization of 3D magnetohydrodynamic channel flow [texte imprimé] / Vazquez, Rafael, Auteur ; Eugenio Schuster, Auteur ; Krstic, Miroslav, Auteur . - 2009 . - 10 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 4 (Juillet 2009) . - 10 p. Mots-clés : boundary  feedback  law;  magnetohydrodynamic  channel  flow;  Navier–Stokes  equations;  Reynolds  numbers Résumé : We present a boundary feedback law that stabilizes the velocity, pressure, and electromagnetic fields in a magnetohydrodynamic (MHD) channel flow. The MHD channel flow, also known as Hartmann flow, is a benchmark for applications such as cooling, hypersonic flight, and propulsion. It involves an electrically conducting fluid moving between parallel plates in the presence of an externally imposed transverse magnetic field. The system is described by the inductionless MHD equations, a combination of the Navier–Stokes equations and a Poisson equation for the electric potential under the MHD approximation in a low magnetic Reynolds number regime. This model is unstable for large Reynolds numbers and is stabilized by actuation of velocity and the electric potential at only one of the walls. The backstepping method for stabilization of parabolic partial differential equations (PDEs) is applied to the velocity field system written in appropriate coordinates. Control gains are computed by solving a set of linear hyperbolic PDEs. Stabilization of nondiscretized 3D MHD channel flow has so far been an open problem. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...]

Compensation of time-varying input and state delays for nonlinear systems / Nikolaos Bekiaris-Liberis in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 134 N° 1 (Janvier 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 1 (Janvier 2012) . - 14 p. Titre : Compensation of time-varying input and state delays for nonlinear systems Type de document : texte imprimé Auteurs : Nikolaos Bekiaris-Liberis, Auteur ; Krstic, Miroslav, Auteur Année de publication : 2012 Article en page(s) : 14 p. Note générale : Dynamic systems Langues : Anglais (eng) Mots-clés : Asymptotic  stability  Control  system  synthesis  Delays  Feedback  Lyapunov  methods  Nonlinear  control  systems  Predictive  control  Time-varying  systems Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : We consider general nonlinear systems with time-varying input and state delays for which we design predictor-based feedback controllers. Based on a time-varying infinite-dimensional backstepping transformation that we introduce, our controller achieves global asymptotic stability in the presence of a time-varying input delay, which is proved with the aid of a strict Lyapunov function that we construct. Then, we “backstep” one time-varying integrator and we design a globally stabilizing controller for nonlinear strict-feedback systems with time-varying delays on the virtual inputs. The main challenge in this case is the construction of the backstepping transformations since the predictors for different states use different prediction windows. Our designs are illustrated by three numerical examples, including unicycle stabilization. DEWEY : 553 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000001 [...] [article] Compensation of time-varying input and state delays for nonlinear systems [texte imprimé] / Nikolaos Bekiaris-Liberis, Auteur ; Krstic, Miroslav, Auteur . - 2012 . - 14 p. Dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 1 (Janvier 2012) . - 14 p. Mots-clés : Asymptotic  stability  Control  system  synthesis  Delays  Feedback  Lyapunov  methods  Nonlinear  control  systems  Predictive  control  Time-varying  systems Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : We consider general nonlinear systems with time-varying input and state delays for which we design predictor-based feedback controllers. Based on a time-varying infinite-dimensional backstepping transformation that we introduce, our controller achieves global asymptotic stability in the presence of a time-varying input delay, which is proved with the aid of a strict Lyapunov function that we construct. Then, we “backstep” one time-varying integrator and we design a globally stabilizing controller for nonlinear strict-feedback systems with time-varying delays on the virtual inputs. The main challenge in this case is the construction of the backstepping transformations since the predictors for different states use different prediction windows. Our designs are illustrated by three numerical examples, including unicycle stabilization. DEWEY : 553 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000001 [...]

Dead-time compensation for wave/string PDEs / Krstic, Miroslav in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 133 N° 3 (Mai 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 133 N° 3 (Mai 2011) . - 13 p. Titre : Dead-time compensation for wave/string PDEs Type de document : texte imprimé Auteurs : Krstic, Miroslav, Auteur Année de publication : 2011 Article en page(s) : 13 p. Note générale : Systèmes dynamiques Langues : Anglais (eng) Mots-clés : Asymptotic  stability  Delays  Feedback  Multidimensional  systems  Parabolic  equations  Partial  differential  equations Index. décimale : 629.8 Résumé : Smith predictorlike designs for compensation of arbitrarily long input delays are commonly available only for finite-dimensional systems. Only very few examples exist, where such compensation has been achieved for partial differential equation (PDE) systems, including our recent result for a parabolic (reaction-diffusion) PDE. In this paper, we address a more challenging wave PDE problem, where the difficulty is amplified by allowing all of this PDE's eigenvalues to be a distance to the right of the imaginary axis. Antidamping (positive feedback) on the uncontrolled boundary induces this dramatic form of instability. We develop a design that compensates an arbitrarily long delay at the input of the boundary control system and achieves exponential stability in closed-loop. We derive explicit formulae for our controller's gain kernel functions. They are related to the open-loop solutions of the antistable wave equation system over the time period of input delay (this simple relationship is the result of the design approach). DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013300 [...] [article] Dead-time compensation for wave/string PDEs [texte imprimé] / Krstic, Miroslav, Auteur . - 2011 . - 13 p. Systèmes dynamiques Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 133 N° 3 (Mai 2011) . - 13 p. Mots-clés : Asymptotic  stability  Delays  Feedback  Multidimensional  systems  Parabolic  equations  Partial  differential  equations Index. décimale : 629.8 Résumé : Smith predictorlike designs for compensation of arbitrarily long input delays are commonly available only for finite-dimensional systems. Only very few examples exist, where such compensation has been achieved for partial differential equation (PDE) systems, including our recent result for a parabolic (reaction-diffusion) PDE. In this paper, we address a more challenging wave PDE problem, where the difficulty is amplified by allowing all of this PDE's eigenvalues to be a distance to the right of the imaginary axis. Antidamping (positive feedback) on the uncontrolled boundary induces this dramatic form of instability. We develop a design that compensates an arbitrarily long delay at the input of the boundary control system and achieves exponential stability in closed-loop. We derive explicit formulae for our controller's gain kernel functions. They are related to the open-loop solutions of the antistable wave equation system over the time period of input delay (this simple relationship is the result of the design approach). DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013300 [...]

Étude des métaux par microscopie électronique en transmission (MET). Microscope, échantillons et diffraction / Krstic, Miroslav

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Motion planning and tracking for tip displacement and deflection angle for flexible beams / Antranik A. Siranosian in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 3 (Mai 2009) 

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Nonlinear control of the viscous burgers equation / Krstic, Miroslav in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N°2 (Mars/Avril 2009) 

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Parameter identification for electrohydraulic valvetrain systems / James Gray in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 133 N° 6 (Novembre 2011) 

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