A branch and bound approach for minimizing the energy consumption of an electrical vehicle

National audienceIn this paper we discuss about the way to approximate the solution of an optimal control problem with a switched command. Our Method is based on a discretization technique associated with a Branch and Bound algorithm. The problem that we focus on is the minimization of the consumption of the energy of an electrical vehicle during some imposed displacements

Optimal time control to swing-up the inverted pendulum-cart in open-loop form

National audienceThis work deals with simulation on an Inverted Pendulum (IP). The control strategy of an IP is split into two main control phases: (i) swing-up control to bring back the pendulum from the downward position to the upward one, and (ii) upright stabilization control to maintain the pendulum to the upright vertical position. In the case (ii), a feedback or a neuro-fuzzy controller is used to stabilize the pendulum cart, while in the first case (i), a non-linear controller based on the energy of the pendulum is used in order to reach the desired performance with a minimum number of swings. Our contribution is to present a simulation using MatLab of time-optimal control system for swinging-up the pendulum, with a single control law in an open-loop form. From the bang-bang structure of the time-optimal control resulting from the necessary condition of the Pontryagin Maximum Principle, the solution obtained from direct discretization method is adjusted by using Newton based method

Modélisation des structures en bois en environnement variable

Les propriétés mécaniques du bois dans les structures dépendent fortement de l état hydrique du matériau. Il en est d ailleurs montré un couplage mécanosorptif fort. Le caractère aléatoire de l environnement climatique impose donc une meilleure modélisation du comportement hygroscopique du bois pour pouvoir estimer les variations de l humidité interne en intégrant les processus de transfert de chaleur et de masse. Si les effets de l humidité sur le comportement a largement été étudié, ce travail permet d aborder les effets de l état mécanique sur les lois de transfert, aussi bien au niveau des conditions limites d échange qu au niveau des propriétés de diffusion. Dans ce contexte, nous proposons une approche thermodynamique et expérimentale permettant d introduire, dans les codes aux éléments finis, un algorithme de transfert couplé plus réaliste.Mechanical properties of timber constructions depend strongly on moisture content state. In this context, it is shown a mecanosorptive coupling. This climatic environment aspect imposes a hygroscopic behavior modeling in order to estimate moisture content variations by integrating the heat and mass transfer processes. If the effect of moisture content on the mechanical behavior has been studied in the literature, this work enables us to precise effects of mechanical state on the transfer laws by taking into account boundary conditions and diffusion properties. In this context, we propose a thermodynamic and experimental approaches which allow to introduce a realistic coupled transfer algorithm in a finite element software.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Modelling of the sorption hysteresis for wood

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[Modeling sorption hysteresis in hygroscopic materials] : Modélisation des hystérésis de sorption dans les matériaux hygroscopiques

International audienceThis article deals with a sorption/desorption model in a hygroscopic material which is derived of the thermodynamic study of the phase equilibrium between the free water and its saturated vapor pressure. This model presents the hysteresis and cyclic variation aspects of the environment relative humidity. The sorption isotherm traduces the explanation of the equilibrium between the bound water phase in the material and the vapor pressure in the environment. This model allows expressing partial variation in the relative humidity domain under variable temperature. A good fitting is obtained with experimental results

Estimation H^1 pour la solution de l'équation de Lamé avec conditions au bord mixte

In this paper we consider Lamé's system of equations on a polygonal domain with mixed boundary conditions of Dirichlet-Neumann type. An explicit L^2 norm estimate for the gradient of the solution of this problem is established. This leads to an explicit bound of the H^1 norm of this solution. Note that the obtained bounds are not optimal .On considère dans cet article le système d'équations de Lamé posé sur un domaine polygonal avec conditions au bord mixtes de type Dirichlet-Neumann. On établit une estimation en norme L^2 explicite pour le gradient de la solution de ce problème. Ce qui permet de majorer explicitement la norme H^1 de cette solution. Noter que les majorations obtenues ne sont pas optimales

Passive RFID technology in pulse wave mode

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