Diagonalisation des modèles linéaires simple-entrée structurés en second ordre

Les modèles linéaires structurés en second-ordre (MSSO) sont des modèles dont la dynamique interne est décrite par un système d'équations différentielles linéaires du second degré. Lorsque les modèlent vérifient les propriétés structurelles, ils peuvent décrire des systèmes mécaniques. Dans un objectif de réduction de modèle, ce papier traite du découplage des équations différentielles des MSSO simple-entrée par diagonalisation des matrices du modèle. Si les conditions de Rayleigh-Caughey sont respectées, alors les résultats classiques de la décomposition modale sont retrouvés

Troncature modale des systèmes port-hamiltoniens linéaires par approche énergétique

Ce papier traite du problème de réduction de l'ordre des modèles de systèmes conservatifs pouvant se mettre sous forme port-hamiltonienne. L'aspect conservatif empêche l'utilisation des techniques les plus répandues se fondant sur les valeurs singulières de Hankel ou sur la norme Hinf. L'approche proposée est une troncature modale qui repose sur un critère énergétique des modes propres. Cette approche permet de prendre en compte non seulement la dynamique interne du système mais aussi la notion d'entrée/sortie de ce dernier

Modified Intelligent Driver Model

The intelligent Driver Model (IDM) is an Adaptive Cruise Control (ACC) model which is wide used in transportation research. Although implementation simplicity in case of simulation, this model has drawbacks in terms of respect of the vehicle’s capability and driver safety. This paper presents the stateof- the art of the IDM and the applied modifications to overcome its drawbacks

Low Speed Automation, a French Initiative

Nowadays, vehicle safety is constantly increasing thanks to the improvement of vehicle passive and active safety. However, on a daily usage of the car, traffic jams remains a problem. With limited space for road infrastructure, automation of the driving task on specific situation seems to be a possible solution. The French project ABV, which stands for low speed automation, tries to demonstrate the feasibility of the concept and to prove the benefits. In this article, we describe the scientific background of the project and expected outputs. Comment: TRA (2012) Document type: Conference objec

Generalized velocity–density model based on microscopic traffic simulation

In case of the Intelligent Driver Model (IDM) the actual Velocity–Density law V(D) applied by this dynamic system is not defined, only the dynamic behaviour of the vehicles/drivers is determined. Therefore, the logical question is whether the related investigations enhance an existing and known law or reveal a new connection. Specifically, which function class/type is enhanced by the IDM? The publication presents a model analysis, the goal of which was the exploration of a feature of the IDM, which, as yet, ‘remained hidden’. The theoretical model results are useful, this analysis important in the practice in the field of hybrid control as well. The transfer of the IDM groups through large-scale networks has special practical significance. For example, in convoys, groups of special vehicle, safety measures with delegations. In this case, the large-scale network traffic characteristics and the IDM traffic characteristics should be taken into account simultaneously. Important characteristics are the speed–density laws. In case of effective modelling of large networks macroscopic models are used, however the IDMs are microscopic. With careful modelling, we cannot be in contradiction with the application of speed–density law, where there IDM convoy passes. Therefore, in terms of practical applications, it is important to recognize what kind of speed–density law is applied by the IDM convoys in traffic. Therefore, in our case the goal was not the validation of the model, but the exploration of a further feature of the validated model. The separate validation of the model was not necessary, since many validated applications for this model have been demonstrated in practice. In our calculations, also the applied model parameter values remained in the range of the model parameters used in the literature. This paper presents a new approach for Velocity–Density Model (VDM) synthesis. It consists in modelling separately each of the density and the velocity (macroscopic parameter). From this study, safety time headway (microscopic parameter) can be identified from macroscopic data by mean of interpolation method in the developed map of velocity–density. By combining the density and the velocity models, a generalized new VDM is developed. It is shown that from this one, some literature VDMs, as well as their properties, can be derived by fixing some of its parameters. First published online 12 April 201

Low Speed Automation, a French Initiative

Nowadays, vehicle safety is constantly increasing thanks to the improvement of vehicle passive and active safety. However, on a daily usage of the car, traffic jams remains a problem. With limited space for road infrastructure, automation of the driving task on specific situation seems to be a possible solution. The French project ABV, which stands for low speed automation, tries to demonstrate the feasibility of the concept and to prove the benefits. In this article, we describe the scientific background of the project and expected outputs

Extension d'un système de perception embarqué par communication (application à la diminution du risque routier)

Cette thèse aborde la coopération possible entre des systèmes de perception embarqués grâce à l utilisation de technologies de télécommunications dans le but de diminuer le risque routier et d améliorer les systèmes d aide à la conduite. Après avoir reconstruit son environnement proche (carte locale), chaque véhicule équipé communique sa carte locale aux autres afin de pouvoir construire une carte dite étendue. Après avoir montré que des communications de type alerte contribuent à la diminution du risque routier, cette thèse propose une étude sur l utilisation de communications généralisées permettant la construction de cartes étendues. Les limites des communications montrent que les informations échangées peuvent présenter de très forts retards. Ce constat amène la nécessité de la construction d une étape de fusion de données robuste. Pour cela, la construction de cartes étendues est décomposée en deux étapes : une étape de recalage des informations et une étape d association. La première étape cherche à recaler les informations présentes dans deux cartes différentes. Pour cela, différentes variantes du filtre de Kalman ont été étudiées afin de trouver l algorithme qui convient le mieux à notre problématique. Ensuite, il convient d associer entre eux les différents objets présents dans les deux cartes. Cette étape se fonde sur la théorie de l évidence. Le système peut ne pas prendre de décision dans le cas d un conflit trop fort entre les différentes informations.This thesis studies the cooperation between embedded perception systems thanks to communication in order to improve the road safety. After having rebuild the close environment (local map), equipped vehicles exchange the local maps in order to build an extended map.After having shown that warning communications improve the road safety, this thesis studies the use of general communications allowing the construction of extended maps. The limits of communication show that exchanged data can be strongly delayed or can be unavailable. Thus a robust data fusion step is needed.To carry out this fusion, the construction of extended maps is split into two steps: a predictive step and an associative step. For the predictive step, we carry out a comparison of several Kalman filters for non-linear system in order to ensure the best algorithm to our problematic. Then, when data from two local maps are retiming and represented in the same space, objects resulting from the two local maps are associated thanks to an algorithm based on the belief theory. One good property of this algorithm is that if the conflict between data is strong, the system can take no decision.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Young Duality and Schmidt-pair for Linear Systems

International audienceThis paper studies the concepts of reachability, observability, controllability and constructibility focusing on the principle of duality with time reversal. This work takes into account linear time-varying systems in continuous time. A discussion is proposed about the Legendre transforms of energy functions and the significance of Schmidt-pairs

Modal truncation for linear Hamiltonian systems : a physical energy approach

International audienceThis paper proposes a new criterion to select the eigenmodes to be left out in a modal truncation procedure. This criterion takes account of the dynamics of the system, on the one hand, and the input/output matrices of the system, on the other. Therefore, this approach is satisfactory from a system and control theory point of view. Moreover, this criterion is physically meaningful because its computation is directly linked with the physical energy supplied to each eigenmode

Model order-reduction for discrete-time switched linear systems

International audienceThis article describes the problem of model order-reduction for a class of hybrid discrete-time switched linear systems composed of linear discrete-time invariant subsystems with a switching rule. This article investigates two novel approaches to model order-reduction. The first approach consists in evaluating the error approximation performance; the problems are solved using the robust stability results of the switched systems. The second approach presents the reachability and observability Gramians of the switched systems, which allows a balanced truncation model reduction procedure. A numerical example shows the effectiveness of the proposed approaches