Using discrete-time hyperchaotic-based asymmetric encryption and decryption keys for secure signal transmission

In this paper, a framework for the synchronization of two non-identical discrete-time hyperchaotic systems, namely the 3D Baier-Klein and the 3D Hitzel-Zele maps, based on the use of hybrid output feedback concept and aggregation techniques, is employed to design a two-channel secure communication system. New sufficient conditions for synchronization are obtained by the use of Borne and Gentina practical criterion for stabilization study associated to the forced arrow form matrix for system description. The efficiency of the proposed approach to confidentially recover the transmitted message signal is shown via an application to the hyperchaotic Baier-Klein and Hitzel-Zele systems, considered as generators of asymmetric encryption and decryption keys

Discrete-time synchronization of chaotic systems for secure communication

This paper deals with the problem of designing an exact nonlinear reconstructor for discrete-time chaotic encrypted messages. More precisely, we investigate the problem of designing a discrete-time dead-beat observer for nonlinear systems with unknown inputs. The application of the proposed observer in the context of secure communication and data transmission is also investigated

Fouling Detection in Heat Exchangers

This paper deals with the design of a nonlinear observer for the purpose of detecting the fouling phenomenon that commonly occurs in heat exchangers. First, the general model of the heat exchanger is presented in terms of partial differential equations. Next, a simplified lump model is derived that is suitable for the observer design. The observer gains are generated by using appropriate Lyapunov functions, equations and inequalities

Analyse biomécanique multidimensionnelle du geste de tourner le volant chez les conducteurs sans déficiences motrices

Tourner le volant d une automobile peut s avérer difficile pour les conducteurs ayant des déficiences motrices des membres supérieurs. En effet, ce mouvement demande une grande mobilité et une force musculaire non négligeable. A ce jour, les directions assistées automobiles sont réglées uniquement sur le ressenti des conducteurs sans déficiences motrices. Le projet ANR VTT VolHand, dans lequel ce travail de recherche s inscrit, ambitionne d apporter une réponse à cette problématique. L objectif de cette thèse est de renseigner la biomécanique du geste déjà chez le conducteur sans déficiences motrices (sain). Pour cela, l interaction main/volant, ainsi que la cinématique (ex. angles articulaires) et la dynamique (ex. efforts sur volant, efforts articulaires) du geste de tourner le volant sont étudiés au travers de plusieurs analyses multidimensionnelles multivariables (atemporelle et temporelle). La méthode originale proposée s appuie sur un découpage flou du volant et des variables cinématiques et dynamiques. La population expérimentée compte une centaine de sujets, dont 23 sujets sans déficience motrice. La plateforme expérimentale regroupe principalement un simulateur automobile compact permettant le recueil des efforts développés par chaque main, une consigne de suivi de trajectoire incitant le conducteur à reproduire un angle désiré et un système optoélectronique mesurant le geste de tourner le volant.Les résultats de l analyse de l interaction main/volant mettent en évidence 3 profils de conducteurs : les conducteurs croiseurs, les conducteurs croiseurs asymétriques et les conducteurs non croiseurs. L analyse des variables cinématiques et dynamiques montrent que les variables dynamiques résultant du tirer/pousser le volant sont discriminantes. Deux nouveaux profils sont alors identifiés : les pousseurs moyens et les tireurs. En majorité, les conducteurs sains tendent à croiser les mains et à pousser sur le volant lors de la réalisation d un geste de tourner le volant à basse vitesse.Plusieurs perspectives sont proposées à court terme, à moyen terme et à long terme. L une d entre elles concerne l adaptation de l assistance aux caractéristiques motrices des conducteurs avec déficience motrice.Steering wheel can be difficult for divers with disabilities on upper limb. Indeed, the steering action might require a large range of motion of upper limb and some muscular strength. Power steering systems that are currently proposed in car were implemented to match non disabled driver feelings and needs. ANR VTT VolHand project wants to enlarge the field of power steering system to drivers with disabilities on upper limbs. The present work is a part of this project. As a preliminary approach, the objective was to analyze the upper limb motion of healthy drivers during a steering exercise. Different multivariable analyses (low level of time summarizing and high level of time summarizing) were done to study hand/wheel interactions, kinematics variables (e.g. joint angles) and dynamics variables (e.g. joint torques). An original fuzzy windowing was proposed to describe hand position on steering wheel, kinematic and dynamics variables. One hundred subjects participated to experiment, included 23 healthy subjects, which consisted on a low speed steering task. The experimental platform was composed of a compact driving simulator, that allow the measurement of each hand effort on the steering wheel, a steering exercise based on a line following protocol, and a motion capture system.Analysis of hand/wheel interaction showed the existence of three driver profiles: hand crossing, asymmetric hand crossing and non hand crossing. Analysis of kinematics and dynamics variables showed that pulling/pushing forces were also discriminating. As a consequence, two additional profiles were identified: mean pushing drivers and pulling drivers. Overall, healthy drivers were hand crossing and mean pushing drivers during a low speed steering task.Short, middle and long prospects are proposed. One of them concerns automotive power steering system adaptation for disabled drivers.VALENCIENNES-Bib. électronique (596069901) / SudocSudocFranceF

Développement d'une méthode de pesage embarqué pour poids lourd

Avec plus de 75% du fret dans la plupart des pays de l UE, le mode routier reste le plus dominant pour le transport de marchandises. La proportion de Poids Lourds (PL) croît dans le trafic routier et atteint souvent 15 à 20%. Pour atteindre les nouveaux objectifs de développement durable, garantir la durabilité des infrastructures et améliorer la sécurité routière, une attention particulière doit être portée sur ce mode de transport pour évaluer et limiter les charges dynamiques des roues et essieux sur les chaussées. La sécurité et l efficacité des PL peuvent être améliorées par l utilisation de systèmes embarqués permettant la surveillance continue et l estimation des charges dynamiques en temps réel. Les progrès des outils de l automatique fournissent des techniques intéressantes pour le pesage en marche embarqué. L objectif de cette thèse est de développer une méthode d estimation des forces d impacts des poids lourds sur les chaussées et de proposer un contrôle actif pour réduire les effets dynamiques maximaux. Après un état de l art détaillé sur les techniques de pesage embarqué disponibles, un modèle lacet-roulis dynamique du PL est développé. Des méthodes d estimations basées sur l inversion explicite et implicite du modèle et d observateurs à mode glissant sont développées et testés à l aide du simulateur Prosper/Callas et une première validation a été obtenue par des tests expérimentaux. Enfin, une architecture de commande par braquage actif, basée sur les forces d impact estimées et permettant d alerter et d assister le conducteur en présence de risque de renversement et de situations accidentogènes a été proposée.With more than 75% of freight in most EU countries, road traffic is the most dominant mode for the transport of goods. The proportion of heavy duty vehicles (HDV) increases in traffic and often reaches 15 to 20%. To achieve the new objectives of sustainable development, ensuring the sustainability of infrastructure and improving road safety, a special attention should be paid to this mode of transportation to assess and reduce the dynamic loads of the wheels and axles on pavements. The safety and efficiency of HDV can be improved by the use of on-board systems for the monitoring and the estimation of dynamic loads in real time. The progress in development of new tools in control theory provides interesting techniques for the weigh-in-motion board. The objective of this thesis is to develop a method to estimate the impact forces of heavy vehicles on the roadways and to provide an active control to reduce the maximum dynamic effects. After a detailed state of art about available on-board weighing technology, a yaw-roll model dynamics of the HDV is developed. Estimation methods based on explicit and implicit model inversion and sliding mode observers are developed and tested using the Prosper/Callas simulator and a first validation is obtained by experimental tests. Finally, control architecture for active steering, based on the estimated impact forces in order to alert and assist the driver in the presence of rollover risk and dangerous situations is proposed.VALENCIENNES-BU Sciences Lettres (596062101) / SudocSudocFranceF

Designing r-sliding mode control using smooth iterative manifolds

In this paper we discuss some specific issues related to higher order sliding mode control design. We highlight the efficiency of such control design with respect to finite time convergence and robustness in the case where the system possesses a relative degree greater than one. We also point out some difficulties that arise due to the fact that eventually some derivative terms becomes very large. In addition, we also propose a smooth sliding manifold for the case where the system possesses a relative degree greater than one. The problem of practical finite-time stability is also discussed. Finally, we present an illustrative example for third order sliding mode

Design and practical implementation of a back-emf sliding-mode observer for a brushless dc motor

A sliding-mode observer is proposed in order to estimate the phase-to-phase trapezoidal back-EMF in a brushless DC motor by using only the measurements of the stator currents and voltages. The main feature of the proposed observer is that it is not sensitive to the switching noise and no filtering is required. The back-EMF estimate was then used to deduce the six rotor positions of the motor. In addition, a method to obtain an estimate of the rotor speed of the motor, by exploiting the mathematical relationship between the speed and the back-EMF, is presented. The observer of the trapezoidal back-EMF is implemented practically on a DSP board. Simulation and experimental results are given to show the performance of the observer

Speed sensorless flux observer for induction machines

In this paper, we present a methodology for the design of a speed sensorless flux observer for induction motors using a behavioral model of the angular speed. We start by developing a reduced order model of the induction motor using complex differential equations. After that, we formulate a behavioral model whose data represents the angular speed of the physical model of the induction motor. This has been done because the original equation governing the rotor speed within the physical model of the machine is highly nonlinear and too complicated to analyse. Furthermore, we use the developed behavioral model in order to design the speed sensorless flux observer for induction motors. The validity of the proposed approach is verified from simulation of the model of the induction motor's flux observer