Dynamic Control of the Quattro Robot by the Leg Edges

International audienceThis paper discusses variable selection for the efficient dynamic control of the Quattro parallel robot through an inverse dynamic model expressed by means of leg orientations. A selection is made within a group of variables where each can imply the state of the robot. Besides, in this work, steering a parallel robot dynamically using its self-projection onto the image plane (where the edges of the lower-legs are exploited in control) is proposed and validated for the first time. In the light of the realistic control simulation, the formative points of better control of the Quattro robot are figured out

FROM’MIR : Développer des outils de prédiction et de conseil pour maîtriser la fromageabilité des laits destinés à la fabrication des fromages traditionnels franc-comtois

Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche finalisée et innovation" de 2014. Il a été réalisé sous l’égide du GIS Relance Agronomique.Mid-infrared spectroscopy prediction equations of the cheese-making properties of milk, established inthe Franche-Comté PDO/PGI context, exist for the first time in France. Laboratory curd yield in DryMatter was consistent with the yields observed in mini-manufactures of soft and pressed cookedcheeses and it is the best predicted parameter. Under our conditions, some coagulation properties suchas curd firmness could be estimated. The acidification properties, which heavily depend on themicrobiological component of milk, are poorly estimated. The best prediction performances wereobtained on individual cow milks. The performances were poorer on the scale of bulk milks, herd tankmilk but especially dairy vat milk. The study of variation factors made it possible to highlight theimportant weight of genetics with a high level of heritability and strong effects of the genome regionsinvolved. The quality and quantity of fodder and the distribution of calves were influential in the contextstudied. In this same context, few factors of variation have been identified at the scale of dairy vat milks,as the practices were very much governed by the PDO specifications. At the end of this project, anobservatory, from the quality of the milk to the quality of the cheese, will be set up in Franche Comté.Studies will also be carried out at the national level to consolidate and improve the equations in othercontexts.Des équations MIR (spectrométrie moyen infrarouge) d'estimation de la fromageabilité des laits,établies en contexte AOP/IGP franc-comtois, existent pour la première fois en France. Le rendementlaboratoire extrait sec (ES), cohérent avec les rendements observés en mini-fabrications de fromages àpâte molle et à pâte pressée cuite, est le paramètre le mieux prédit. Dans nos conditions, certainsaspects de l'aptitude à la coagulation enzymatique, comme la fermeté des gels, peuvent être estimés.L’aptitude à l’acidification, dépendant fortement de la composante microbiologique des laits, est quant àelle mal estimée. Les meilleures performances de prédiction sont obtenues sur les laits individuels devaches. Les performances sont moins bonnes à l’échelle des laits de mélange, des laits de troupeauxmais surtout des laits de cuves de fromagerie. L'étude des facteurs de variation a permis de mettre enévidence le poids important de la génétique avec un niveau d’héritabilité élevé et des effets forts desrégions du génome impliquées. La qualité et la quantité de fourrages ainsi que la répartition desvêlages sont influents dans le contexte étudié. Dans ce même contexte, peu de facteurs de variationont été mis en évidence à l’échelle des laits de cuves, les pratiques étant très encadrées par le cahierdes charges AOP. A l’issue de ce projet, un observatoire, depuis la qualité des laits jusqu’à celle desfromages, va être mis en place en Franche Comté. Des études seront aussi mises en œuvre au niveaunational pour permettre notamment une consolidation et une amélioration des équations dans d'autrescontextes

A simulation study on the effects of neuronal ensemble properties on decoding algorithms for intracortical brain-machine interfaces

Background: Intracortical brain-machine interfaces (BMIs) harness movement information by sensing neuronal activities using chronic microelectrode implants to restore lost functions to patients with paralysis. However, neuronal signals often vary over time, even within a day, forcing one to rebuild a BMI every time they operate it. The term "rebuild" means overall procedures for operating a BMI, such as decoder selection, decoder training, and decoder testing. It gives rise to a practical issue of what decoder should be built for a given neuronal ensemble. This study aims to address it by exploring how decoders' performance varies with the neuronal properties. To extensively explore a range of neuronal properties, we conduct a simulation study. Methods: Focusing on movement direction, we examine several basic neuronal properties, including the signal-to-noise ratio of neurons, the proportion of well-tuned neurons, the uniformity of their preferred directions (PDs), and the non-stationarity of PDs. We investigate the performance of three popular BMI decoders: Kalman filter, optimal linear estimator, and population vector algorithm. Results: Our simulation results showed that decoding performance of all the decoders was affected more by the proportion of well-tuned neurons that their uniformity. Conclusions: Our study suggests a simulated scenario of how to choose a decoder for intracortical BMIs in various neuronal conditions

Game Plan: What AI can do for Football, and What Football can do for AI

The rapid progress in artificial intelligence (AI) and machine learning has opened unprecedented analytics possibilities in various team and individual sports, including baseball, basketball, and tennis. More recently, AI techniques have been applied to football, due to a huge increase in data collection by professional teams, increased computational power, and advances in machine learning, with the goal of better addressing new scientific challenges involved in the analysis of both individual players' and coordinated teams' behaviors. The research challenges associated with predictive and prescriptive football analytics require new developments and progress at the intersection of statistical learning, game theory, and computer vision. In this paper, we provide an overarching perspective highlighting how the combination of these fields, in particular, forms a unique microcosm for AI research, while offering mutual benefits for professional teams, spectators, and broadcasters in the years to come. We illustrate that this duality makes football analytics a game changer of tremendous value, in terms of not only changing the game of football itself, but also in terms of what this domain can mean for the field of AI. We review the state-of-the-art and exemplify the types of analysis enabled by combining the aforementioned fields, including illustrative examples of counterfactual analysis using predictive models, and the combination of game-theoretic analysis of penalty kicks with statistical learning of player attributes. We conclude by highlighting envisioned downstream impacts, including possibilities for extensions to other sports (real and virtual)

Stabilité dynamique des véhicules légers tout-terrain. Nouvelles solutions. Application aux véhicules légers de type quad

This dissertation addresses the topic of lateral dynamic stability of light All-Terrain Vehicles (ATV) in natural environment. In particular, the development of both a lateral rollover indicator and an active device dedicated to ATV stability is investigated, with a special focus on the experimental application to quad bikes vehicles. Therefore, this work proposes global algorithms for rollover indicator computation and control, based on the following three robotic fields : modelling, observation and control theory. First, a dynamic model, taking account of sliding phenomena and pilot behavior, is proposed so as to detect lateral rollover by means of the Lateral Load Transfer (LLT) anticipation and computation. Observers, dedicated to on-line grip conditions estimation, are then used to supply models with the estimated variables. Finally, a predictive control law permits to ensure the vehicle lateral stability, as validated through various experimentations.La problématique de cette thèse réside dans l'étude et le maintien de la stabilité dynamique latérale des Véhicules Légers Tout Terrain (VLTT) évoluant en milieu naturel. Elle s'attache plus particulièrement au développement d'indicateurs de risque pour l'aide à la conduite ainsi qu'au développement de systèmes de sécurité actifs dédiés aux VLTT, avec comme cadre expérimental privilégié, l'application à la stabilité latérale des véhicules quadricyles à moteur communément appelés quads. Cette thèse propose des algorithmes de calcul d'un indicateur de risque et de commande globaux, exploitant trois domaines connexes de la robotique : la modélisation, l'observation et la commande. Un modèle dynamique, intégrant les glissements et le comportement du pilote, est d'abord proposé afin de caractériser le renversement latéral de l'engin au travers du calcul et de l'anticipation de Transfert de Charge Latéral (TCL). Des observateurs capables d'estimer en temps réel l'adhérence sont utilisés pour alimenter ce modèle. Enfin une loi commande prédictive permet d'assurer la stabilité latérale de l'engin, validée par de nombreuses expérimentation

Pertes de substances acquises maxillaires et mandibulaires et réhabilitation prothétique (impacts sur la déglutition)

Ce travail traite de l impact des pertes de substance acquises maxillaires et mandibulaires sur la déglutition. Elles sont majoritairement dues à des exérèses carcinologiques. Les conséquences qui en résultent sont graves et n affectent pas uniquement la prise alimentaire. En effet, les voies aéro-digestives supérieures étant le centre des grandes fonctions de la face, la phonation sera également atteinte. C est pourquoi la réalisation de deux thèses jumelées semblait judicieuse. Le rôle du chirurgien-dentiste est primordial dans l accompagnement de ces patients qui se retrouvent démunis face à leur handicap. Pour cette raison, il est indispensable de connaître l impact de ces résections sur la phonation et la déglutition. Ces deux grandes fonctions siégeant au sein des mêmes cavités, l anatomie de celles-ci, les étiologies et la prise en charge des pertes de substance ainsi que les thérapeutiques liées à la réhabilitation ont été décrites dans une partie commune. La physiologie, quant à elle, sera détaillée indépendamment dans chaque thèse ainsi qu une revue de littérature tentant de répondre à la problématique du sujet. Dans une dernière partie, nous verrons que la chirurgie et les traitements par radiothérapie et chimiothérapie associés peuvent impliquer une disparition des structures et des éléments physiologiques indispensables à la déglutition. L objectif sera alors de restaurer la fonction pour limiter les conséquences dramatiques de ce handicap sur la vie du patient.LILLE2-UFR Odontologie (593502202) / SudocSudocFranceF

Controlling Parallel Robots during Singular Assembly Mode Changing

International audienceIn order to increase the reachable workspace of parallel robots, a promising solution consists of the definition of optimal trajectories that ensure the non-degeneracy of the dynamic model in the Type 2 (or parallel) singularity and allow to cross it. However, this assumes that the control law can perfectly track the desired trajectory, which is impossible due to modeling errors. This paper improves the results obtained previously by two of the authors of the present work that defined a robust multi-model approach allowing parallel robots to cross Type 2 singularities. The main idea was to shift near singularities the general dynamic model to a simplified one that can never degenerate. However, because in Type 2 singularity, the robot is locally overconstrained, we will show that the simplified dynamic model admits infinity of exact solutions. We propose to use the solution leading to a null overconstraint in order to avoid undesirable effects near singularities, such as buckling or unstability. The mentioned multi-model control approach is modified accordingly and it is then applied on a prototype of five-bar mechanism to show the effects of correctly and not-correctly managed overconstraint

Singularity analysis and reconfiguration mode of the 3-CRS parallel manipulator

International audienceThe 3-CRS manipulator is an original parallel mechanism having 6 degrees of freedom (DOFs) with only 3 limbs. This mechanism uses a motorized cylindrical joint per limb. This new paradigm of actuation opens research fields on new families of robots that should particularly interest the parallel robotics community. According to its dimensional synthesis, this mechanism can have remarkable kinematic properties such as a large orientation workspace or reconfiguration capabilities. In this paper, we introduce this mechanism and we study its singularities by using a geometric approach. This approach simplifies considerably singularity analysis problem by considering the relative geometric configurations of three planes defined by the distal links of the limbs. Thanks to that, a reconfiguration mode of the 3-CRS, that doubles its reachable workspace, is highlighted. This property is illustrated on a physical prototype of the robot

Dynamics-based Algorithm for Reliable Assembly Mode Tracking in Parallel Robots

International audienceFinding the current pose of the end-effector of a parallel robot is a problem, since its forward geometric model generally has several solutions. Current methods to address this problem operate mainly under the assumption that the robot never changes its assembly mode nor gets close to Type 2 singularities. Nonetheless, recent works proved that a parallel robot can change its assembly mode thanks to dedicated trajectory generation and control. Such a feature allows increasing the operational workspace of such manipulators. Hence tracking correctly the end-effector pose while crossing Type 2 singularities, is mandatory for a practical usage of this workspace enhancement method. However, on Type 2 singularities several solutions of the forward geometric model merge, making current tracking methods ineffective. To fill this gap, we propose a two-step pose-tracking methodology: First, a differential inclusion based on kinematics and dynamics is solved. Second, joint measurements are used to tighten resulting enclosures. The effectiveness of this method is discussed thanks to experimental data gathered on a planar parallel robot