Convergence d'observateurs flous sous formes descripteurs : application à l'homme en station debout

International audienceUne classe d'observateurs non linéaires sous forme descripteurs basée sur une modélisation de type Takagi-Sugeno (TS) est décrite. Les conditions de convergence de l'erreur de reconstruction sont obtenues sous la forme de problèmes LMI. L'intérêt de ce type de représentation est, pour certains modèles non linéaires, de réduire la conservativité des résultats classiques. Cette réduction se fait au travers de la réduction du nombre de règles du modèle TS. Une application à la biomécanique de l'homme en station debout est proposée. Un observateur à entrées inconnues est défini afin d'estimer les vitesses et couples articulaires à partir de mesures de positions obtenues par un système optoélectronique de capture du mouvement

Solid-state-biased coherent detection of ultra-broadband terahertz pulses

Significant progress in nonlinear and ultrafast optics has recently opened new and exciting opportunities for terahertz (THz) science and technology, which require the development of reliable THz sources, detectors, and supporting devices. In this work, we demonstrate the first solid-state technique for the coherent detection of ultra-broadband THz pulses (0.1–10 THz), relying on the electric-field-induced second-harmonic generation in a thin layer of ultraviolet fused silica. The proposed CMOS-compatible devices, which can be realized with standard microfabrication techniques, allow us to perform ultra-broadband detection with a high dynamic range by employing probe laser powers and bias voltages much lower than those used in gas-based techniques. Eventually, this may pave the way for the use of high-repetition-rate ultrafast lasers and commercially available electronics for the coherent detection of ultrashort THz pulses

Evaluation de stratégies de commande pour véhicules hybride paralleles

Hybrid vehicles are usually propelled by one or two electric motor and an internal combustion engine. The first part of this study presents some classical mechanical arrangements and describes the prototype built at the LAMIH during a previous project. Algorithms, called control strategy, are used to choose at each sampling time the power split between the engine and the motor. Some of them rely on empiric rules and uses fuzzy controllers and other deals with more detailed energy flow analysis. Then the choice of the power split is written into the form of an optimization under constraint problem. Several algorithms based on the optimal control theory are proposed. The aim is to compute, in simulation, the control sequence that ensures the lowest fuel consumption. A new control strategy is derived from the global optimization algorithm and a second one is proposed, based on the analysis of the global optimization results. Several criterions are proposed in order to characterize speed cycles, to evaluate control strategies. A comparison of several control strategies shows that one of the proposed control strategies provides best results, closed to those of the global optimization algorithm. At last, the use of the global optimization algorithm for the choice of the mechanical arrangement and sizing the engine and the motor is explained in the last section.électriques associés à un moteur thermique. La première partie décrit les grandes familles d'architectures et le prototype réalisé au LAMIH au cours de travaux précédents. La deuxième partie est consacrée à l'étude d'algorithmes, appelés stratégies de commande, qui choisissent à chaque instant la répartition de puissance entre les deux chaînes de traction. Les approches envisagées reposent soit sur l'utilisation du formalise flou et mettent en oeuvre des règles de bon sens soit sur l'analyse plus fine des échanges énergétiques au sein du groupe motopropulseur. La répartition de puissance entre les différentes motorisations est ensuite écrite sous la forme d'un problème d'optimisation globale sous contraintes. Plusieurs algorithmes basés sur la théorie de la commande optimale sont alors proposés. L'objectif est de rechercher, en simulation, la séquence de commandes qui minimise de la consommation de carburant. Dans la dernière partie, les résultats des algorithmes d'optimisation globale sont utilisés, dans un premier temps pour proposer deux nouvelles stratégies de commande temps réel. Ensuite, une étude basée sur des critères permettant de caractériser les cycles de vitesses et les performances des stratégies de commande a notamment permis de valider les stratégies proposées. Enfin, l'utilisation des algorithmes d'optimisation globale comme outil d'aide au dimensionnement et aux choix d'architecture est illustré dans la dernière partie

Active Side Shafts Torsion Damping Control for Hybrid Electric Vehicles

International audienceHybrid electric vehicles generally use an internal combustion engine and one or several electric drives. Optimization-based energy management strategies computes a power split between both the engine and the machine to minimize the fuel consumption. Nevertheless, the driving comfort is not taken into account. Due to its high torque bandwidth, the electric machine can be used to improve driving comfort. The objective of this paper is to propose the use the electric machine to actively damp the encountered side-shafts torque oscillations. The driveshaft torsional behavior is described and the corresponding comfort issues are highlighted. Simulations results have been done for the nominal case and to validate the controller behavior with respect to some un-modeled parameter variations

Brake and velocity model-free control on an actual vehicle

International audienceA tuning procedure for the model-free control paradigm introduced in Fliess and Join (2013) is proposed. This controller requires an estimate of the system dynamics usually obtained using an ALIEN filter, presented in Fliess and Sira-Ramírez (2003). Several implementation issues of this ALIEN filter, such as the order of the numerical quadrature, are discussed and overcome. Finally, the control law is applied to two systems: the low-level braking system of a vehicle and its longitudinal speed control. Experimental results on a real vehicle are provided and compared with a classic PI controller

MEGEVH project: graphical modeling for energy management of hybrid electric vehicles

EET-2007 European Ele-Drive Conference, BRUXELLES, BELGIQUE, 30-/05/2007 - 01/06/2007The French national MEGEVH project deals with energy management of hybrid electric vehicles (HEV). The objective is to provide general methodologies to model HEV and optimize their energy flows. The project is subdivided in modeling and optimization sub-projects. Graphical modeling has been chosen to highlight energetic properties of the studied vehicles. Two actual vehicles are taking as reference for the developments. Theoretical methods will be first developed independently of the kind of HEV. Then these methods will be tested on the reference vehicles. The MEGEHV objectives and organization are firstly detailed. In a second section, Energetic Macroscopic Representation of a parallel HEV is described as an example of use of graphical modeling for energy management

MEGEVH project: graphical modeling for energy management of hybrid electric vehicles

EET-2007 European Ele-Drive Conference, BRUXELLES, BELGIQUE, 30-/05/2007 - 01/06/2007The French national MEGEVH project deals with energy management of hybrid electric vehicles (HEV). The objective is to provide general methodologies to model HEV and optimize their energy flows. The project is subdivided in modeling and optimization sub-projects. Graphical modeling has been chosen to highlight energetic properties of the studied vehicles. Two actual vehicles are taking as reference for the developments. Theoretical methods will be first developed independently of the kind of HEV. Then these methods will be tested on the reference vehicles. The MEGEHV objectives and organization are firstly detailed. In a second section, Energetic Macroscopic Representation of a parallel HEV is described as an example of use of graphical modeling for energy management