Modeling and Calibration of Coupled Fish-Eye CCD Camera and Laser Range Scanner for Outdoor Environment Reconstruction

International audiencePrecise and realistic models of outdoor environments such as cities and roads are useful for various applications. In order to do so, geometry and photography of environments must be captured. We present in this paper a coupled system , based on a fish-eye lens CCD camera and a laser range scanner, aimed at capturing color and geometry in this context. To use this system, a revelant model and a accurate calibration method are presented. The calibration method uses a simplified fish-eye model; the method uses only one image for fish-eye parameters, and avoids the use of large calibration pattern as required in others methods. The validity and precision of the method are assessed and example of colored 3D points produced by the system is presented

Kinematics of regional salt flow in the northern Gulf of Mexico

International audienceThe kinematics of regional-scale salt flow in the northern Gulf of Mexico is analysed using: (i) a map of shelf-break contours at the termination of successive depositional episodes; (ii) the location and geometry of large-scale structures of the slope domain as imaged by seismics; and (iii) digital slope bathymetry. In the north margin, salt has flowed towards the SW since the Cretaceous with three main stages of development prior to, during and after a massive salt extrusion in the Early Miocene time. The corresponding sequence of structural development is discussed using a laboratory model. Contrary to all previous interpretations that invoked sedimentary loading as the main driving force, the analysis of regional-scale salt flow implies that the salt tectonics of the northern Gulf of Mexico is predominantly controlled by gliding above the margin dip. The SWdirected salt flow indicates that the north margin of the northern Gulf of Mexico trendsNW-SE, in agreement with plate kinematic models in which the Yucatan continental block has undergone a 45-608 dextral rotation relative to its present orientatio

Identificació electrònica en animals de companyia

Treball presentat a l'assignatura de Deontologia i Veterinària Legal (21223

A robust multivariable control for an electropneumatic system using backstepping design

International audienceDuring the last twenty years, the parallel development of pneumatic systems and control theory has lead to the implementation of modern control laws in pneumatic devices. This paper deals with the robust control problem of a pneumatic actuator subjected to mass flow leakage inside the servodistributor and load disturbances. The control strategy is based on backstepping design. For this, backstepping is presented in an informal setting. The nonlinear model of the electropneumatic system is presented. This one is transformed to be nonlinear affine model and a coordinate transformation is then related to make possible the implementation of the nonlinear controller. Control laws are developed using backstepping design to control position and pressure. The robustness visa -vis modeling errors and some unknown terms is proved. Finally, the experiment results are presented and discussed

Pressure regulator stability analysis in electropneumatic

International audienceThis paper aims at giving a analytical approach of the stability analysis of control pressure components in pneumatic domain. Some authors have given some results in linear case especially in the hydraulic context [Meritt 1960, Mac Cloy et al 1980, Margolis 1997, Alirand et al. 2002]. The structure and the technologies of commonly used pneumatic pressure control component are firstly introduced, and then a non-linear model is proposed as the basis for the stability analysis. The classical linear method, based on the tangent linearized model is applied to determine the analytical stability conditions using Routh-Hurwitz criteria. The root loci are finally studied according to a set of equilibrium points which corresponds to various conditions of use. In this last part, an existing pressure regulator is used as an example and allows the development of an analysis concerning the dynamic performances on realistic basis. To conclude, the proposed approach gives a set of design rules which enables the system parameters to be sized according to the required dynamic performances and stability

Control design for energy saving

International audienceThis paper presents the interest of including control strategy into electropneumatic design. For this certain experimental results obtained in an electropneumatic process have been presented. Using two servo-distributors leads to a system with one degree of freedom. This opportunity is exploited for in two objectives. The first concerns positioning control and the second attempts to optimise energy efficiency. With this aim an energy optimisation algorithm has been presented. The chosen control algorithm issues from the flatness concept. KEY WORDS nonlinear control, flatness, energy saving, electropneumatic

Hybrid control for switching between position and force tracking

International audienceThis paper is the logical result of previous researches about advanced control in electropneumatic systems. After different works in feedback control of electropneumatic actuators in position tracking [1] or in force tracking [2], this study led about a method to switch between these two different focuses. This question is an important problem in many industrial systems, for example in the case of vehicle active suspension or for pneumatic or hydraulic pliers, fingers and spot welding, fatigue test. Indeed, some dangerous damages could occur when the aim is to move a load near a structure and to apply a force against this structure. The major difficulty is to know when and how to switch between the position control and the force control (this is here the notion of hybrid control). A classical occurrence is due to a static position error when the control algorithm switches from position feedback to force feedback. The result leads very often to an undesirable impact to the structure. KEYWORDS Force / position tracking, hybrid control, pneumatic

L'Automatique pour les systèmes "Fluid Power"

National audienceL'objectif de cette présentation est de présenter les problèmes d'automatique dans le cadre des systèmes mécatroniques à fluide sous pression : électropneumatiques et électrohydrauliques. Ce sujet très vaste sera abordé via la présentation d'exemples de réalisations effectuées en partenariat entre le Laboratoire Ampère et des industriels (Asco Joucomatic, Renault Trucks, MD Electronic, DGA-MBDA, CNES…). Le Laboratoire Ampère fait partie du réseau européen 'Fluid Power Centres in Europe' (http://www.fpce.net/), et intervient en temps qu'expert dans le cadre du dimensionnement, de la modélisation, de la simulation et de la commande des systèmes électropneumatiques. Cet exposé présentera d'une part un bref état de l'art des activités liant Fluid Power et Automatique et d'autre part abordera quelques prospectives sur cette thématique.Le monde du Fluid Power est très vaste et les contours du domaine étudié seront présentés. Les systèmes qui seront détaillés ont été conçus pour actionner une charge afin de la déplacer selon différents modes de fonctionnement : régulation, asservissement ou suivi de trajectoire. Dans la plupart des cas, il a fallu développer des techniques de commande dites "avancées" pour satisfaire les spécifications. En effet, ces systèmes à fluides sous pression comportent de fortes non linéarités dues à la compressibilité des fluides utilisés (surtout dans le cas de l'air), aux lois d’écoulements à travers les restrictions situées au niveau des modulateurs de puissance utilisés (servodistributeurs, régulateur de pression), aux pertes de charges dans les circuits de transmissions (surtout dans le cas de l'huile), à la présence de frottements secs non négligeables sur des applications demandant une grande précision, aux commutations rapides de certains organes de commande (électrovannes). Ainsi, la synthèse de commandes non linéaires trouve ici tout sont intérêt. Ces lois de commandes sont d'autant plus efficaces si la connaissance du système permet d'obtenir des modèles précis exploitables pour leur synthèse. Ces commandes peuvent utiliser les capteurs physiques présents au niveau des modulateurs de puissances, actionneurs, charge, mais également au niveau de la source d'énergie, de l'environnement ou à partir de capteurs logiciels (observateurs) synthétisés dans le calculateur

Design of a compliant positioning control using an inverse method

International audienceThe design of new system requires generally achieving different objectives. The choice of the right system and control architecture is crucial and they can be judiciously exploited. The proposed approach is dealing with the efficient use of a pneumatic cylinder controlled by two servovalves. The control objectives are independent position and stiffness tracking. A Bond graph approach gives, in a first step, a general methodology to check the accessibility of the specifications on energetic and dynamic criteria. Then a control algorithm issued from the flatness concept and the nonlinear control theory is developed. Simulation and experimental results illustrating the proposed principle are finally presented. Concerning the tracking performance, it is shown that the new strategy does not decrease tracking errors, or the static errors, or the standard deviation in term of position and velocity tracking. The performance of the stiffness control is finally illustrated in simulation