CoreBot M : Le robot de la Team CoreBots préparé pour l'édition 2011 du défi Carotte

3 pagesNational audienceLa deuxième édition du défi CAROTTE, organisé par l'ANR et la DGA, aura lieu fin juin à Bourges. Son objectif : vérifier la capacité de petits robots terrestres pour des missions de reconnaissance en environnement intérieur. Après avoir remporté l'édition 2010, la Team CoreBots présente son nouveau robot dédié à l'édition 2011. Sans en révéler tous les secrets, ce papier expose les grandes lignes de notre architecture et de notre stratégie

Pile à combustible, production d'hydrogène à partir de biomasse, stockage d'hydrogène sur carbones nanostructurés, analyse du cycle de vie : un projet du groupe des Ecoles des Mines en génie des procédés, énergie et environnement (GEM GP E2)

International audienceLes équipes de différents centres de recherche des Ecoles des Mines, impliquées dans les domaines liés à la filière hydrogène, se sont regroupées au sein du Groupe des Ecoles des Mines en Génie des Procédés, Energie et Environnement (GEM GP E2). Le projet H2-PAC mis en place, a ainsi permis de regrouper les compétences de ces équipes pour aborder de manière plus efficace les quatre problématiques suivantes : les piles à combustible à membrane échangeuse de protons, la production d'hydrogène à partir de biomasse, le stockage d'hydrogène sur matériaux carbonés nanostructurés et l'analyse du cycle de vie. Dans chacun de ces thèmes des progrès ont été enregistrés et les équipes se sont mutuellement enrichies de nouvelles connaissances. Le projet a dans l'ensemble permis de créer des liens entre les différentes équipes impliquées, qui permettront de futures collaborations et la concrétisation de nouveaux projets

Development of colloidal suspension spraying application to the fabrication of dense YSZ coatings for SOFCs

The colloidal suspension spraying is being considered as an alternative coating process to the plasma spraying for SOFCs. It consists in spraying a suspension with nanoparticles of the required material through an air atomizing bi-fluid nozzle. After drying, the green coating are sinterd in air to obtain the final microstructure. In this work, the implementation of this process was investigated for the coating of dense electrolyte for SOFCs applications. First of all, an optimization of the layering process was made by modelling. A strategy consisting in coating several layers with a shift of the nozzle was successfully applied to obtain homogeneous coating. An optimum was found for 4 layers coating. Experimentally, standard suspensions were sprayed on top of various substrates in order to characterize the homogeneity of the coating. By changing the air pressure of the atomization, the parameters yielding to a semi-elliptic distribution of the spray pattern gave the best results in term of homogeneity in agreement with the modelling. The samples were sintered in air at 1300 °C (due to technical limitation with oven), but it was unfortunately not possible to obtain fully dense layer because of the low sintering temperature. However homogeneous coatings with 10 μm in thickness were obtain and suggest the opportunity to obtain dense films with a thickness between 5 and 10 μm. Major improvement could be achieved by optimizing the formulation of the suspension in order to increase the compacity of the green layers and avoid defects. In parallel to these tasks, the development of a software and the design of an automated system was made in order to control the spraying process with a computer

Design and construction of an autonomous hybrid ground/air drone for indoor applications

Ce travail est dédié au contrôle non linéaire d'un drone de type quadricoptère dont la spécificité est de pouvoir voler aussi bien que se déplacer en glissant sur le sol, à la façon d'un aéroglisseur. Dans un contexte d'exploration autonome de bâtiment, ce concept hybride permet d'économiser les batteries lorsqu'il n'est pas nécessaire de voler puisque le drone profite des surfaces planes pour se déplacer sans avoir à compenser la gravité ; il peut ainsi prolonger l'autonomie au-delà de la vingtaine de minutes typique d'un quadricoptère classique. Contrairement aux véhicules terrestres à roues, les capacités de franchissement de notre drone sont fortement augmentées car son aptitude au vol l'autorise à éviter les obstacles, à changer d'étage ou passer par une fenêtre. L'étude menée ici concerne essentiellement le déplacement surfacique de ce drone hybride, et vise à concevoir et implémenter une loi de contrôle capable d'asservir ce système sur des trajectoires planes au sol. Ce drone terrestre est similaire à un système sous actionné de type glisseur ; le problème de la stabilisation en un point est donc distingué du suivi de trajectoire en raison de la condition de Brockett que ce système ne satisfait pas ; notre plateforme ne peut donc pas être stabilisée par des retours d'états continus. En s'appuyant sur la littérature, cette thèse propose différentes approches théoriques en temps variant, fonctions transverses, platitude ou encore par "Backstepping" pour répondre à ces problèmes. Après une phase d'identification du modèle dynamique employé, la partie expérimentale, exploitant un système de Motion Capture pour récupérer les informations de position et d'orientation du système, valide ces lois de contrôle et de commande pour le suivi d'une trajectoire circulaire simple.This thesis is dedicated to the non-linear control of a special hybrid quadrotor which is able to fly, and slide on the ground like an hovercraft. In the context of an autonomous indoor exploration this hybrid concept allows saving energy when flying is not necessary, since the drone can then slide on the ground without having to compensate for the gravity; autonomy can last beyond the 20 minutes typical of a standard quadrotor. Contrarily to wheeled mobile robots, the hybrid drone ability to move across space is strongly increased since it can fly to avoid obstacles, to move between two levels, to get in through a window. The study under consideration is essentially focused on the displacement of the drone on the ground and aims at designing and implementing a control law so that our system is able to track a 2D xy plane trajectory. This terrestrial quadrotor is similar to a slider underactuated vehicle. The point stabilisation is then separately studied from the trajectory tracking issue because of the Brockett condition, which is not satisfied in that case; our platform cannot be stabilized by means of continuous state feedbacks. This thesis proposes different theoretical developments based on the literature and deriving from time varying control laws, transverse functions, flatness or backstepping techniques to solve both point stabilisation and trajectory tracking. The experimental part of the thesis is based on the recovering of the drone position in real time and orientation via a Motion Capture system for feedback loop in the control law; the proposed dynamical model was validated as well as the control and command laws for the tracking of a circular trajectory

Conception et réalisation d'un drone hybride sol/air autonome

This thesis is dedicated to the non-linear control of a special hybrid quadrotor which is able to fly, and slide on the ground like an hovercraft. In the context of an autonomous indoor exploration this hybrid concept allows saving energy when flying is not necessary, since the drone can then slide on the ground without having to compensate for the gravity; autonomy can last beyond the 20 minutes typical of a standard quadrotor. Contrarily to wheeled mobile robots, the hybrid drone ability to move across space is strongly increased since it can fly to avoid obstacles, to move between two levels, to get in through a window. The study under consideration is essentially focused on the displacement of the drone on the ground and aims at designing and implementing a control law so that our system is able to track a 2D xy plane trajectory. This terrestrial quadrotor is similar to a slider underactuated vehicle. The point stabilisation is then separately studied from the trajectory tracking issue because of the Brockett condition, which is not satisfied in that case; our platform cannot be stabilized by means of continuous state feedbacks. This thesis proposes different theoretical developments based on the literature and deriving from time varying control laws, transverse functions, flatness or backstepping techniques to solve both point stabilisation and trajectory tracking. The experimental part of the thesis is based on the recovering of the drone position in real time and orientation via a Motion Capture system for feedback loop in the control law; the proposed dynamical model was validated as well as the control and command laws for the tracking of a circular trajectory.Ce travail est dédié au contrôle non linéaire d'un drone de type quadricoptère dont la spécificité est de pouvoir voler aussi bien que se déplacer en glissant sur le sol, à la façon d'un aéroglisseur. Dans un contexte d'exploration autonome de bâtiment, ce concept hybride permet d'économiser les batteries lorsqu'il n'est pas nécessaire de voler puisque le drone profite des surfaces planes pour se déplacer sans avoir à compenser la gravité ; il peut ainsi prolonger l'autonomie au-delà de la vingtaine de minutes typique d'un quadricoptère classique. Contrairement aux véhicules terrestres à roues, les capacités de franchissement de notre drone sont fortement augmentées car son aptitude au vol l'autorise à éviter les obstacles, à changer d'étage ou passer par une fenêtre. L'étude menée ici concerne essentiellement le déplacement surfacique de ce drone hybride, et vise à concevoir et implémenter une loi de contrôle capable d'asservir ce système sur des trajectoires planes au sol. Ce drone terrestre est similaire à un système sous actionné de type glisseur ; le problème de la stabilisation en un point est donc distingué du suivi de trajectoire en raison de la condition de Brockett que ce système ne satisfait pas ; notre plateforme ne peut donc pas être stabilisée par des retours d'états continus. En s'appuyant sur la littérature, cette thèse propose différentes approches théoriques en temps variant, fonctions transverses, platitude ou encore par "Backstepping" pour répondre à ces problèmes. Après une phase d'identification du modèle dynamique employé, la partie expérimentale, exploitant un système de Motion Capture pour récupérer les informations de position et d'orientation du système, valide ces lois de contrôle et de commande pour le suivi d'une trajectoire circulaire simple

Control of non holonomic or under-actuated mechanical systems: the examples of the unicycle robot and the slider

International audienceThis paper is dedicated to the control of some classes of mechanical systems, not stabilizable by means of at least continuous state feedback laws. This is the case for non holonomic mechanical systems, an example being the unicycle robot, or for under-actuated mechanical systems, an example being the slider. The similarity between these two kinds of dynamical systems will be analyzed, with respect to controllability, stabilizability and flatness properties.The control design for slider stabilization could be viewed, to some extent, as an extension of the control law used for unicycle systems, but it is not so obvious if one wants to stabilize the slider at a chosen reference position, with a chosen fixed orientation. In fact, a new fixed point stabilization result will be given for the slider, and therefore, a switched control strategy will be proposed for both systems, based on differential flatness property to track moving non singular reference trajectories, and switching to periodic time-varying feedback laws to ensure final stabilization at rest equilibrium points. The method will be illustrated with success through simulation results and also first experimental results in the case of a terrestrial quadrotor tracking non singular reference trajectories

New online estimation algorithm of lateral tire-road coefficients based on Inertial Navigation System

International audienceFor the sake of simplicity, control laws for autonomous vehicle mainly use linear tire models, but this modeling is only valid for small slip angles. Hence, to keep this hypothesis valid, tire's behavior has to lie within the limits of handling, i.e. there is a threshold the slip angle cannot surpass. This paper develops a new estimator for the cornering stiffness and maximum lateral friction coefficients. These parameters provide important information on the ground conditions and are beneficial for improving the stability of the vehicle. The algorithm is based on estimated lateral tire forces and on a 3 zones adaptive algorithm, including a Dugoff theoretical tire model. It will allow to set up a model not only for the linear part but for the whole range of slip angles, providing the trend of the tire behavior at each time and informing about the future evolution of lateral forces. The advantage of the algorithm is that no measurement of lateral tire forces is needed and few parameters are required such as yaw rate, longitudinal and lateral velocities obtained through an effective Inertial Navigation System, wheel rotational speeds and steering angles. Simulations conducted on realistic dynamical situation validate the algorithm efficiency

Component-Based Model for Building Material Stock and Waste-Flow Characterization: A Case in the Île-de-France Region

Building demolition is one of the main sources of waste generation in urban areas and is a growing problem for cities due to the generated environmental impacts. To promote high levels of circular economy, it is necessary to better understand the waste-flow composition; nevertheless, material flow studies typically focus on low levels of detail. This article presents a model based on a bottom-up macro-component approach, which allows the multiscale characterization of construction materials and the estimation of demolition waste flows, a model that we call the BTP-flux model. Data mining, analytical techniques, and geographic information system (GIS) tools were used to assess different datasets available at the national level and develop a common database for French buildings: BDNB. Generic information for buildings in the BDNB is then enriched by coupling every building with a catalog of macro-components (TyPy), thus allowing the building’s physical description. Subsequently, stock and demolition flows are calculated by aggregation and classified into 32 waste categories. The BTP-flux model was applied in Île-de-France in a sample of 101,320 buildings for residential and non-residential uses, representative of the assessed population (1,968,242 buildings). In the case of Île-de-France, the building stock and the total demolition flows were estimated at 1382 Mt and 4065 kt, respectively. For its inter-regional areas—departments—, stock and demolition waste can vary between 85 and 138 tons/cap and 0.263 and 0.486 tons/cap/year, respectively. The mean of the total demolition wastes was estimated at 0.33 tons/cap/year for the region. Results could encourage scientists, planners, and stakeholders to develop pathways towards a circular economy in the construction sector by implementing strategies for better management of waste recovery and reintegrating in economic circuits, while preserving a maximum of their added value.ISSN:2071-105

High Risk of Anal and Rectal Cancer in Patients With Anal and/or Perianal Crohn’s Disease

International audienceBackground & AimsLittle is known about the magnitude of the risk of anal and rectal cancer in patients with anal and/or perineal Crohn’s disease. We aimed to assess the risk of anal and rectal cancer in patients with Crohn’s perianal disease followed up in the Cancers Et Surrisque Associé aux Maladies Inflammatoires Intestinales En France (CESAME) cohort.MethodsWe collected data from 19,486 patients with inflammatory bowel disease (IBD) enrolled in the observational CESAME study in France, from May 2004 through June 2005; 14.9% of participants had past or current anal and/or perianal Crohn’s disease. Subjects were followed up for a median time of 35 months (interquartile range, 29–40 mo). To identify risk factors for anal cancer in the total CESAME population, we performed a case-control study in which participants were matched for age and sex.ResultsAmong the total IBD population, 8 patients developed anal cancer and 14 patients developed rectal cancer. In the subgroup of 2911 patients with past or current anal and/or perianal Crohn’s lesions at cohort entry, 2 developed anal squamous-cell carcinoma, 3 developed perianal fistula–related adenocarcinoma, and 6 developed rectal cancer. The corresponding incidence rates were 0.26 per 1000 patient-years for anal squamous-cell carcinoma, 0.38 per 1000 patient-years for perianal fistula–related adenocarcinoma, and 0.77 per 1000 patient-years for rectal cancer. Among the 16,575 patients with ulcerative colitis or Crohn’s disease without anal or perianal lesions, the incidence rate of anal cancer was 0.08 per 1000 patient-years and of rectal cancer was 0.21 per 1000 patient-years. Among factors tested by univariate conditional regression (IBD subtype, disease duration, exposure to immune-suppressive therapy, presence of past or current anal and/or perianal lesions), the presence of past or current anal and/or perianal lesions at cohort entry was the only factor significantly associated with development of anal cancer (odds ratio, 11.2; 95% CI, 1.18-551.51; P = .03).ConclusionsIn an analysis of data from the CESAME cohort in France, patients with anal and/or perianal Crohn’s disease have a high risk of anal cancer, including perianal fistula–related cancer, and a high risk of rectal cancer