A Metric Observer for Induction Motors Control

This paper deals with metric observer application for induction motors. Firstly, assuming that stator currents and speed are measured, a metric observer is designed to estimate the rotor fluxes. Secondly, assuming that only stator currents are measured, another metric observer is derived to estimate rotor fluxes and speed. The proposed observer validity is checked throughout simulations on a 4 kW induction motor drive

Cardiogenic shock due to reverse takotsubo syndrome triggered by multiple sclerosis brainstem lesions: a case report and mini review

BackgroundTakotsubo syndrome (TTS) is mainly characterized by chest pain, left ventricular dysfunction, ST-segment deviation on electrocardiogram (ECG) and elevated troponins in the absence of obstructive coronary artery disease. Diagnostic features include left ventricular systolic dysfunction shown on transthoracic echocardiography (TTE) with wall motion abnormalities, generally with the typical “apical ballooning” pattern. In very rare cases, it involves a reverse form which is characterized by basal and mid-ventricular severe hypokinesia or akinesia, and sparing of the apex. TTS is known to be triggered by emotional or physical stressors. Recently, multiple sclerosis (MS) has been described as a potential trigger of TTS, especially when lesions are located in the brainstem.Case summaryWe herein report the case of a 26-year-old woman who developed cardiogenic shock due to reverse TTS in the setting of MS. After being admitted for suspected MS, the patient presented with rapidly deteriorating clinical condition, with acute pulmonary oedema and hemodynamic collapse, requiring mechanical ventilation and aminergic support. TTE found a severely reduced left ventricular ejection fraction (LVEF) of 20%, consistent with reverse TTS (basal and mid ventricular akinesia, apical hyperkinesia). Cardiac magnetic resonance imaging (MRI) performed 4 days later showed myocardial oedema in the mid and basal segments on T2-weighted imaging, with partial recovery of LVEF (46%), confirmed the diagnosis of TTS. In the meantime, the suspicion of MS was also confirmed, based on cerebral MRI and cerebral spinal fluid analyses, with a final diagnosis of reverse TTS induced by MS. High-dose intravenous corticotherapy was initiated. Subsequent evolution was marked by rapid clinical improvement, as well as normalization of LVEF and segmental wall-motion abnormalities.ConclusionOur case is an example of the brain-heart relationship: it shows how neurologic inflammatory diseases can trigger a cardiogenic shock due to TTS, with potentially serious outcomes. It sheds light on the reverse form, which, although rare, has already been described in the setting of acute neurologic disorders. Only a handful of case reports have highlighted MS as a trigger of reverse TTS. Finally, through an updated systematic review, we highlight the unique features of patients with reversed TTS triggered by MS

Fibrin monomers evaluation during hospitalization for COVID-19 is a predictive marker of in-hospital mortality

BackgroundCoagulopathy is one of the main triggers of severity and worsening of Coronavirus disease 2019 (COVID-19) particularly in critically ill patients. D-dimer has been widely used to detect COVID-19 coagulation disorders and has been correlated with outcomes such as disease severity and in-hospital mortality. Involvement of other fibrin degradation products, particularly fibrin monomers (FM), remains an ongoing question.MethodsWe performed a monocentric study of adult patients with COVID-19, who were admitted either in the medical ward (MW) or in the intensive care unit (ICU) and who had FM measurements performed on them during the first wave of COVID-19 outbreak. We analyzed the positivity of FM levels (FM > 7 µg/mL) to assess the ability of FM monitoring during the first days of hospitalization to predict COVID-19 outcomes.ResultsIn our cohort, 935 FM measurements were performed in 246 patients during their first 9 days of hospitalization. During patient follow-up, the FM levels were higher in patients admitted directly to the ICU than in those admitted to the MW. Moreover, we observed significantly increased levels of FM in patients when the data were stratified for in-hospital mortality. At hospital admission, only 27 (11%) patients displayed a positive value for FM; this subgroup did not differ from other patients in terms of severity (indicated by ICU referral at admission) or in-hospital mortality. When analyzing FM positivity in the first 9 days of hospitalization, we found that 37% of patients had positive FM at least once during hospitalization and these patients had increased in-hospital mortality (p = 0.001). Thus, we used non-adjusted Kaplan–Meier curves for in-hospital mortality according to FM positivity during hospitalization and we observed a statistically significant difference for in-hospital mortality (hazard ratio = 1.48, 95% CI: 1.25–1.76, p < 0.001). However, we compared the AUC of FM positivity associated with a ratio of D-dimer >70% and found that this combined receiver operating characteristic (ROC) curve was superior to the FM positivity ROC curve alone.ConclusionMonitoring of FM positivity in hospitalized patients with COVID-19 could be a reliable and helpful tool to predict the worsening condition and mortality of COVID-19

Achievement of the planetary defense investigations of the Double Asteroid Redirection Test (DART) mission

NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by –33.24 minutes, with two independent analysis methods each reporting a 1σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos–Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense

CONCEPTION EVOLUTIONNAIRE DE SYSTEMES ROBOTIQUES

PARIS-BIUSJ-Mathématiques rech (751052111) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Adaptive Learning Control in Evolutionary Design of Mobile Robots,

International audienc

Une approche générique de la commande basée modèle des AUV sous actionnés

Ce travail présente une nouvelle approche pour la commande des véhicules sous marins autonomes(Autonomous Underwater Vehicle, AUV) sous actionnés. Un AUV est dit sous actionné lorsqu’il a moinsde 6 degrés de liberté actionnés. De nombreuses méthodes existent pour aborder la problématique dusous-actionnement. La plupart de ces méthodes consistent à réduire l’espace de calcul aux degrés deliberté actionnés en négligeant les effets concernant les degrés non actionnés. Dans la majorité des cas,les degrés de liberté non actionnés sont mécaniquement stables et leurs effets sont bornés. De ce fait,travailler en espace réduit présente des performances acceptables sur la plupart des tâches.Néanmoins, les approches classiques des problèmes de sous-actionnement mettent en avant de nouveauxinconvénients. Le plus souvent, ces méthodes ne sont pas génériques et ne fonctionnent que pour cer-taines topologies d’actionnement. Par ailleurs, la réduction de l’espace de calcul n’est pas forcémentcompatible avec certains contrôleurs. Dans le cas d’un contrôleur basé sur le modèle cinématique duvéhicule par exemple, la réduction d’espace modifie les propriétés fondamentales des matrices néces-saires à la réalisation du calcul de la commande. Les matrices de changement de repère peuvent ne plusêtre toujours inversibles après réduction. Dans ce cas, la réduction d’espace introduit des combinaisonsd’orientations singulières du robot dans lesquelles le calcul du contrôleur n’est pas faisable.Ce travail propose une nouvelle méthode de commande pour les AUV sous actionnés basée sur lesmodèles cinématique et dynamique du système. Cette approche est générique à toutes les topologies depropulsion (nombre, type, position et orientation des propulseurs) et à tous les contrôleurs ; elle constitueun nouveau paradigme de contrôle pour les véhicules sous marins sous actionnés. La méthode permetd’asservir tous les degrés de liberté actionnés par la topologie de propulsion et d’exploiter les rotationsactionnées pour compenser des translations qui ne le sont pas. Concrètement, la méthode repose surl’utilisation d’une matrice, disons H 2, introduite dans la partie cinématique du calcul de la commande.Cette matrice permet de générer des vitesses de rotation à partir des erreurs sur des translations nonactionnées. L’utilisation de la matrice H est une nouvelle approche qui n’a pas encore été abordée entant que telle dans la littérature.Pour définir la matrice H il est nécessaire de commencer par introduire deux vecteurs. Ces vecteurscodent les degrés de liberté dans le repère du robot. On définit le vecteur des degrés de liberté actionnésau centre du repère mobile hO et le vecteur des degrés de liberté nécessaires au point traquant 3 hE . Cesdeux vecteurs peuvent être différents mais doivent être compatibles. On peut par exemple asservir unetranslation de hE grâce à une rotation de hO mais pas l’inverse et pas sur le même axe. La matrice H estgénérée par un algorithme qui parcoure ces deux vecteurs, trouve quelle translation de hE n’est pas danshO et grâce à quelle rotation de hO elle peut être contrôlée. La matrice permet de calculer une vitesse decommande en rotation au centre du robot basée sur l’erreur en position au point traquant. Le calcul desefforts de commande se fait ensuite dans l’espace complet et est générique pour toutes les topologies depropulsion et toutes les combinaisons de degrés de liberté.La méthode est appliquée sur plusieurs topologies de propulsion et sur plusieurs tâches mais surtout dansle cas classique d’un robot actionné en cavalement et en lacet qui se déplace dans un plan horizontal.Dans ce cas, on montre qu’il est possible avec cette méthode d’asservir soit l’embardée soit le lacet durobot sur la trajectoire ce qui s’avère impossible avec d’autres méthodes

Magnetic design and analysis of a radial reconfigurable magnetic coupling thruster for vectorial AUV propulsion

International audienc

Design of an Optimally Stiff Axial Magnetic Coupling for Compliant Actuators

International audienceManoeuvrability is one of the essential keys in the development of improved autonomous underwater vehicles for challenging missions. In the last years, more researches were dedicated to the development of new hulls shapes and thrusters to assure more manoeuvrability. The present review explores various enabling technologies used to implement the vectorial thrusters (VT), based on water-jet or propellers. The proposals are analysed in terms of added degrees of freedom, mechanisms, number of necessary actuators, water-tightness, electromagnetomechanical complexity, feasibility, etc. The usage of magnetic coupling thrusters (conventional or reconfigurable) is analysed in details since they can assure the development of competitive full waterproof reconfigurable thrusters, which is a frictionless, flexible, safe, and low-maintenance solution. The current limitations (as for instance the use of non conductive hull) are discussed and ideas are proposed for the improvement of this new generation of underwater thrusters, as extending the magnetic coupling usage to obtain a fully contactless vector thrust transmission

Advances in Reconfigurable Vectorial Thrusters for Adaptive Underwater Robots

International audienceManoeuvrability is one of the essential keys in the development of improved autonomous underwater vehicles for challenging missions. In the last years, more researches were dedicated to the development of new hulls shapes and thrusters to assure more manoeuvrability. The present review explores various enabling technologies used to implement the vectorial thrusters (VT), based on water-jet or propellers. The proposals are analysed in terms of added degrees of freedom, mechanisms, number of necessary actuators, water-tightness, electromagnetomechanical complexity, feasibility, etc. The usage of magnetic coupling thrusters (conventional or reconfigurable) is analysed in details since they can assure the development of competitive full waterproof reconfigurable thrusters, which is a frictionless, flexible, safe, and low-maintenance solution. The current limitations (as for instance the use of non conductive hull) are discussed and ideas are proposed for the improvement of this new generation of underwater thrusters, as extending the magnetic coupling usage to obtain a fully contactless vector thrust transmission