A Unifying Framework for Finite Wordlength Realizations.

A general framework for the analysis of the finite wordlength (FWL) effects of linear time-invariant digital filter implementations is proposed. By means of a special implicit system description, all realization forms can be described. An algebraic characterization of the equivalent classes is provided, which enables a search for realizations that minimize the FWL effects to be made. Two suitable FWL coefficient sensitivity measures are proposed for use within the framework, these being a transfer function sensitivity measure and a pole sensitivity measure. An illustrative example is presented

La réception des littératures étrangéres.

Sin resume

Direct and Steering Tilt Robust Control of Narrow Vehicles

International audienceNarrow Tilting Vehicles (NTVs) are the convergence of a car and a motorcycle. They are expected to be the new generation of city cars considering their practical dimensions and lower energy consumption. However, due to their height to breadth ratio, in order to maintain lateral stability, NTVs should tilt when cornering. Unlike the motorcycle, where the driver tilts the vehicle himself, the tilting of an NTV should be automatic. Two tilting systems are available; Direct and Steering Tilt Control, the combined action of these two systems being certainly the key to improve considerably NTV dynamic performances. In this paper, multivariable control tools (H2 methodology) are used to design, in a systematic way, lateral assistance controllers driving DTC, STC or both DTC/STC systems. A three degrees of freedom model of the vehicle is used, as well as a model of the steering signal, leading to a two degrees of freedom low order controller with an efficient feedforward anticipative part. Taking advantage of all the available measurements on NTVs, the lateral acceleration is directly regulated. Finally, a gain-scheduling solution is provided to make the DTC, STC, and DTC/STC controllers robust to longitudinal speed variations

Finite Wordlength Controller Realizations using the Specialized Implicit Form

Une forme d'état implicite spécialisée est présentée pour étudier les effets de l'implantation en précision finie des régulateurs. Cette forme permet une description macroscopique des algorithmes à implanter. Elle constitue un canevas unificateur permettant de décrire les différentes structures utilisées pour l'implantation, telles que les réalisations avec l'opérateur delta, la forme directe II en rho, la forme d'état-observateur et bien d'autres formes qui sont d'habitude traitées séparément dans la littérature. Différentes mesures quantifiant les effets de l'implantation sur le comportement en boucle fermée sont définis dans ce contexte. Elles concernent aussi bien la stabilité que la performance. L'écart entre la réalisation à précision infinie et la réalisation à précision finie est évaluée selon la mesure de sensibilité des coefficients et la mesure du bruit de quantification. Le problème consistant à trouver une réalisation dont l'implantation amène un minimum de dégradation peut alors est résolut numériquement. Cette approche est illustrée avec deux exemples

Non-linear control of a Narrow Tilting Vehicle

International audience— Narrow Tilting Vehicles (NTVs) are the convergence of a car and a motorcycle. They are expected to be the new generation of city cars considering their practical dimensions and lower energy consumption. But considering their height to breadth ratio, in order to maintain lateral stability, NTVs should tilt when cornering. Unlike the motorcycle's case, where the driver tilts the vehicle himself, the tilting of an NTV should be automatic. Two tilting systems are available; Direct and Steering Tilt Control, the combined action of these two systems being certainly the key to improve considerably NTVs dynamic performances. Focusing on the lateral dynamic of NTVs, multivariable control strategies based on linear robust control theory, were already proposed in the literature, assuming decoupling with the longitudinal dynamic. In this paper a 4 DoF model of the main longitudinal and lateral dynamics is considered, and its differential flatness is demonstrated. The three flat outputs have furthermore a particular physical meaning, making possible the design of a simple external control loop complying with the driver demands

Geometric Model of a Narrow Tilting CAR using Robotics formalism

International audienceThe use of an Electrical narrow tilting car instead of a large gasoline car should dramatically decrease traffic congestion, pollution and parking problem. The aim of this paper is to give a unique presentation of the geometric modeling issue of a new narrow tilting car. The modeling is based on the modified Denavit Hartenberg geometric description, which is commonly used in Robotics. Also, we describe the special Kinematic of the vehicle and give a method to analyze the tilting mechanism of it. Primarily experimental results on the validation of the geometrical model of a real tilting car are given

Modelling and Simulation of a Two wheeled vehicle with suspensions by using Robotic Formalism

International audienceModels, simulators and control strategies are required tools for the conception of secure and comfortable vehicles. The aim of this paper is to present an efficient way to develop models for dynamic vehicle, focusing on a two wheeled vehicles whose body involves six degrees of freedom. The resulting model is sufficiently generic to perform simulation of realistic cornering and accelerating behavior in various situations. It may be used in the context of motorcycle modeling, but also in various situations (e.g. for control application) as simplified model for 3 or 4 wheeled (tilting) cars. The approach is based on considering the vehicle as a multi-body poly-articulated system and the modeling is carried out using the robotics formalism based on the modified Denavit-Hartenberg geometric description. In that way, the dynamic model is easy to implement and the system can be used for control applications

Modelling and Simulation of a Two wheeled vehicle with suspensions by using Robotic Formalism

International audienceModels, simulators and control strategies are required tools for the conception of secure and comfortable vehicles. The aim of this paper is to present an efficient way to develop models for dynamic vehicle, focusing on a two wheeled vehicles whose body involves six degrees of freedom. The resulting model is sufficiently generic to perform simulation of realistic cornering and accelerating behavior in various situations. It may be used in the context of motorcycle modeling, but also in various situations (e.g. for control application) as simplified model for 3 or 4 wheeled (tilting) cars. The approach is based on considering the vehicle as a multi-body poly-articulated system and the modeling is carried out using the robotics formalism based on the modified Denavit-Hartenberg geometric description. In that way, the dynamic model is easy to implement and the system can be used for control applications