{"id":226,"date":"2024-11-29T14:26:58","date_gmt":"2024-11-29T13:26:58","guid":{"rendered":"https:\/\/pole-acs.lis-lab.fr\/?p=226"},"modified":"2024-12-02T11:34:25","modified_gmt":"2024-12-02T10:34:25","slug":"soha-kanso-et-william-jussiau","status":"publish","type":"post","link":"https:\/\/pole-acs.lis-lab.fr\/?p=226","title":{"rendered":"Soha Kanso et William Jussiau"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">S\u00e9minaire jeunes chercheurs Diapro &#8211; 21 novembre 2024 &#8211; Saint-J\u00e9r\u00f4me<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Lien vers la vid\u00e9o du s\u00e9minaire <strong>(mot de passe : Diapro)<\/strong> : <a href=\"https:\/\/amupod.univ-amu.fr\/video\/33442-seminaire-diapro-21-11-2024\/\">https:\/\/amupod.univ-amu.fr\/video\/33442-seminaire-diapro-21-11-2024\/<\/a><\/li>\n\n\n\n<li>Lien vers les pr\u00e9sentations : <a href=\"https:\/\/sync.lis-lab.fr\/index.php\/s\/EgC2nCWpZaFz383\">https:\/\/sync.lis-lab.fr\/index.php\/s\/EgC2nCWpZaFz383<\/a><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>William Jussiau, <\/strong>jeune docteur de l&rsquo;ONERA <\/h2>\n\n\n\n<p><strong>Titre<\/strong> : Lois de commande pour le contr\u00f4le des \u00e9coulements oscillateurs<\/p>\n\n\n\n<p><strong>R\u00e9sum\u00e9 <\/strong>: Cette th\u00e8se porte sur la synth\u00e8se de lois de commande pour les \u00e9coulements oscillateurs \u00e0 faible nombre de Reynolds. Nous y \u00e9tudions deux configurations canoniques en 2D : l\u2019\u00e9coulement autour d\u2019un cylindre, et l\u2019\u00e9coulement au-dessus d\u2019une cavit\u00e9 ouverte. Ces deux cas d\u2019\u00e9tude pr\u00e9sentent un \u00e9quilibre stationnaire instable, et un r\u00e9gime d\u2019oscillations auto-entretenues \u2013 respectivement, un cycle limite et un attracteur torique. L\u2019objectif principal est la synth\u00e8se de lois de commande pour supprimer compl\u00e8tement le r\u00e9gime oscillatoire, pour r\u00e9duire la tra\u00een\u00e9e moyenne, les vibrations structurelles ou le rayonnement acoustique tonal. En pratique, la synth\u00e8se de lois de commande pour ces syst\u00e8mes est rendue difficile par la diversit\u00e9 des ph\u00e9nom\u00e8nes dynamiques \u00e9mergeant des \u00e9quations de Navier-Stokes, non-lin\u00e9aires et de dimension infinie. Nous proposons trois m\u00e9thodes distinctes pour r\u00e9aliser cette t\u00e2che, utilisant respectivement une param\u00e9trisation des correcteurs stabilisants, la continuation num\u00e9rique et le formalisme de la r\u00e9solvante moyenne.<br><br><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Soha KANSO, <\/strong>doctorante, CRAN, Universit\u00e9 de Lorraine, Nancy. ATER Polytech Nancy<\/h2>\n\n\n\n<p class=\"has-text-align-left\"><strong>Titre <\/strong>: Safe Reinforcement Learning and Degradation Tolerant Control Design<br><br><strong>R\u00e9sum\u00e9 <\/strong>: Safety-critical dynamical systems are essential in various industries, such as aerospace domain, autonomous systems, robots in healthcare area etc., where violating safety constraints and structural or functional failure may lead to catastrophic consequences. A significant challenge in these systems is the degradation of components and actuators, which can compromise safety and stability of systems. As such, incorporating system\u2019s health state within the control design framework is essential to ensure tolerance to functional degradation. Moreover, such system models often involve uncertainties and incomplete knowledge, especially as components degrade, altering system dynamics in a nonlinear manner. This underscores the necessity for the development of learning approaches that incorporate the available data within the control learning paradigm.<br>In this context, Reinforcement Learning (RL) emerges as a powerful approach, capable of learning optimal control laws for partially or fully unknown dynamic systems, in the presence of input-output data (without the exact knowledge of system models). However, a major challenge in applying RL methods to safety-critical systems lies in ensuring safety during both the exploration and exploitation phases. Exploration involves introducing probing noise to the policy in order to collect  informative data across the state space, while exploitation refers to applying the learned policy to optimize performance in real operations.<br><\/p>\n\n\n\n<p>To this end, this presentation will first explore an off-policy safe RL approach for the regulation and the tracking problem in continuous-time nonlinear systems affine in control input. A novel approach will be presented that ensures system stability and safety during all phases: initialization, exploration, and exploitation. By using  quadratic programming with control Lyapunov function (CLF) and control barrier function (CBF), the proposed approach ensures stability and safety of the system during initialization and exploration phases. Furthermore, during exploitation, the safety of the learned policy is ensured by augmenting the cost function with reciprocal CBFs, thus balancing performance optimization and safety. The second part of the talk will focus on addressing actuator degradation, which poses a critical threat to system performance and stability. A degradation-tolerant controller based on RL is introduced for continuous-time nonlinear systems affine in control input. The objectives are twofold: ensuring system stability despite degradation, and decelerating the degradation rate to complete missions and extend actuator life. This is achieved by imposing constraints on degradation rates using CBFs. Furthermore, a cyclic off-policy algorithm is presented, enabling iterative exploration and  exploitation across multiple learning cycles. This allows for continuous updates of neural network weights with recent information on degradation levels, ensuring that the learned policy effectively stabilizes the system while accounting for degradation effects.<\/p>\n\n\n\n<p>In the developed approaches, neural networks are used to approximate both the value function and the control policy, thereby enabling efficient learning. Simulation results will be presented to demonstrate the efficiency of the proposed approaches.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>S\u00e9minaire jeunes chercheurs Diapro &#8211; 21 novembre 2024 &#8211; Saint-J\u00e9r\u00f4me William Jussiau, jeune docteur de l&rsquo;ONERA Titre : Lois de commande pour le contr\u00f4le des \u00e9coulements oscillateurs R\u00e9sum\u00e9 : Cette th\u00e8se porte sur la synth\u00e8se de lois de commande pour les \u00e9coulements oscillateurs \u00e0 faible nombre de Reynolds. Nous y \u00e9tudions deux configurations canoniques en &hellip; <a href=\"https:\/\/pole-acs.lis-lab.fr\/?p=226\" class=\"more-link\">Continuer la lecture de <span class=\"screen-reader-text\">Soha Kanso et William Jussiau<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-226","post","type-post","status-publish","format-standard","hentry","category-non-classe"],"_links":{"self":[{"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/posts\/226","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=226"}],"version-history":[{"count":3,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/posts\/226\/revisions"}],"predecessor-version":[{"id":229,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=\/wp\/v2\/posts\/226\/revisions\/229"}],"wp:attachment":[{"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pole-acs.lis-lab.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}