Detection and diagnosis of changes in the eigenstructure of nonstationary multivariable systems

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Model changes in signal processing: state of the art and results of GRECO SARTA

The purpose of this paper is to outline the interest of the so-called "model changes" approach for solving Signal Processing problems. We describe what we think to be the state of the art in this field together with the remaining open problems, and we present the results of the CNRS GRECO SARTA working group on this topic. After an introduction to the change detection and estimation problem, we present three typical examples of situations in which change detection techniques can be used . We then give the state of the art together with the main existing references and we list the open problems . Finally, we describe the contribution of the GRECO SARTA in this area and conclude with some future research works.Le but de ce bref article est de mettre en évidence l'intérêt de l'approche dite « ruptures de modèles » en Traitement du Signal, de présenter ce que l'auteur considère comme étant l'état de l'art ainsi que les problèmes ouverts qui demeurent, et d'indiquer le bilan du GRECO SARTA pour ce thème . Après une introduction au problème, on présente trois exemples typiques de situations qui peuvent être abordées à l'aide de techniques de ruptures de modèles . On précise ensuite l'état de l'art avec les principales références existantes, et on indique les problèmes ouverts . Enfin, on décrit l'apport du GRECO SARTA et en conclusion on propose des perspectives

Model-based fault detection and diagnosis : cases study for vibration monitoring

A signal processing approach is presented for detection and diagnosis of fatigues or failures in vibrating mechanical systems subject to natural excitation . Detection and diagnosis is performed while the system being at work, so that the excitation is usually not observed and may involve turbulent phenomena . This is a short report of a 10 years project which involved more than 2 persons per year in mean . The method is illustrated on the following case studies : offshore structures, and rotating machinery.On présente une approche de traitement du signal pour la détection et le diagnostic des fatigues ou usures dans des systèmes mécaniques soumis à une excitation naturelle ou ambiante . La détection et le diagnostic sont réalisés sur le système en fonctionnement habituel, et donc en général avec une excitation non mesurée et présentant des phénomènes de turbulence . Cet article est un bref rapport sur un projet de recherche d'environ 10 ans qui a mobilisé plus de 2 personnes par an en moyenne . La méthode est illustrée sur les deux cas suivants : structures offshore et turbo-alternateurs (') . (') Ce travail a été soutenu pendant 7 ans par 4 contrats avec IFREMER et pendant 4 ans par 2 contrats avec EDF

Biologically-inspired Motion Control for Kinematic Redundancy Resolution and Self-sensing Exploitation for Energy Conservation in Electromagnetic Devices

This thesis investigates particular topics in advanced motion control of two distinct mechanical systems: human-like motion control of redundant robot manipulators and advanced sensing and control for energy-efficient operation of electromagnetic devices. Control of robot manipulators for human-like motions has been one of challenging topics in robot control for over half a century. The first part of this thesis considers methods that exploits robot manipulators’ degrees of freedom for such purposes. Jacobian transpose control law is investigated as one of the well-known controllers and sufficient conditions for its universal convergence are derived by using concepts of “stability on a manifold” and “transferability to a sub-manifold”. Firstly, a modification on this method is proposed to enhance the rectilinear trajectory of the robot end-effector. Secondly, an abridged Jacobian controller is proposed that exploits passive control of joints to reduce the attended degrees of freedom of the system. Finally, the application of minimally-attended controller for human-like motion is introduced. Electromagnetic (EM) access control systems are one of growing electronic systems which are used in applications where conventional mechanical locks may not guarantee the expected safety of the peripheral doors of buildings. In the second part of this thesis, an intelligent EM unit is introduced which recruits the selfsensing capability of the original EM block for detection purposes. The proposed EM device optimizes its energy consumption through a control strategy which regulates the supply to the system upon detection of any eminent disturbance. Therefore, it draws a very small current when the full power is not needed. The performance of the proposed control strategy was evaluated based on a standard safety requirement for EM locking mechanisms. For a particular EM model, the proposed method is verified to realize a 75% reduction in the power consumption

Detection and diagnosis of changes in the Eigenstructure of nonstationary multivariable systems

SIGLECNRS RS 14802 E / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc