Dissertations / Theses on the topic 'Identification de sous-espaces'
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PEKPE, Komi Midzodzi. "Identification par les techniques des sous-espaces - application au diagnostic." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2004. http://tel.archives-ouvertes.fr/tel-00008649.
Pekpe, Komi Midzodzi. "Identification par les techniques des sous-espaces : application au diagnostic." Vandoeuvre-les-Nancy, INPL, 2004. http://www.theses.fr/2004INPL111N.
This thesis focus on MIMa system identification and sensor fault detection and isolation with subspace methods. At the beginning, linear system identification is tackled. First, a presentation of classical subspace methods based on the estimation of the observability matrix and/or state sequence matrix is presented; then a new approach based on a FIR modelling is proposed. This approach is based on the estimation of the Markov parameters which allows the determination of a minimal and balanced realisation using algorithm ERA. Three methods for identification of linear dynamic systems with coloured noises are proposed. Ln the context of switching systems identification, a multiple model modelling with binary weighting functions are used. Two methods are proposed to cope with this unsupervised learning problem: the first carries out a classification withtlchange detection methods, but the second performs this classification by finding hyperplanes which represent the local models in the inputs and outputs space. Both methods estimate a minimal and balanced realisation of each local model by least squares method with the knowledge of the weighting functions obtained by classification. A multiple model approach is used to deal with nonlinear system identification. The weights of the local models are supposed to be known and a method giving a minimal and balanced realisation of each local model is proposed. Finally, sensor fault detection and isolation in linear systems is performed without the knowledge of a model. A method only based on the knowledge of the inputs and outputs is proposed. Since no estimated mode! is used, the proposed method does not suffer from parametric uncertainties. By weighting the state with the high power of the state matrix which is supposed to be stable, the state influence is removed and the input influence is suppressed by orthogonal projection, then, we obtained a structured residual. This residual allows the detection and the isolation of the sensor faults
Ivanova, Elena. "Identification de systèmes multivariables par modèle non entier en utilisant la méthode des sous-espaces." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0561/document.
The identification of systems by fractional models was initiated in the 1990s and various results have been obtained since. Nevertheless, most of these results are based on prediction error methods (PEM) of identification, based on the minimization of the norm of the estimation error. Apparent in 1996, the subspace methods are relatively new in the theory of the identification of linear systems. Based on geometric projections and linear algebra, they present an alternative to classical methods based on linear or nonlinear regression. They allow estimating the matrices of the state-space representation of a system. In the context of fractional systems, a pseudo-state-space representation generalizes the notion of state-space representation by introducing an additional parameter which is the commensurable order.Currently, the subspace method for non-integer systems has only been applied inthe time domain. It is then developed in this thesis for such a class of systems in the frequency domain. Moreover, since non-integer systems are continuous time systems, datapre-filtering is necessary to respect the causality of the signals and to be able to realize the identification. A study of the different filtering methods in the context of subspaceidentification is then carried out in order to deduce their advantages and disadvantages in the time domain. Finally, the method has been applied to a thermal diffusion system.The obtained models are generalized for several input heat flows, considering their temperature available at several measurement points
Mercère, Guillaume. "Contribution à l'identification récursive des systèmes par l'approche des sous-espaces." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2004. http://tel.archives-ouvertes.fr/tel-00007958.
Mestrah, Ali. "Identification de modèles sous forme de représentation d'état pour les systèmes à sortie binaire." Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC255.
This thesis focuses on parametric modeling of invariant linear systems from binary output measurements. This identification problem is addressed via the use ofsubspace methods. These methods allow the estimation of state-space models, an added benefit of these methods being the fact that their implementation doesnot require the prior knowledge of the order of the system. These methods are initially adapted to high resolution data processing, the objective of this thesis istherefore their adaptation to the identification using binary measurements. In this thesis we propose three subspace methods. Convergence properties of two ofthem are established. Monte Carlo simulation results are presented to show the good performance, but also limits, of these methods
Pouliquen, Mathieu. "De l'identification des systèmes : points de vue sur les méthodes des sous-espaces, identification pour la commande." Caen, 2003. http://www.theses.fr/2003CAEN2074.
Bastogne, Thierry. "Identification des systèmes multivariables par les méthodes des sous-espaces. Application à un système d'entraînement de bande." Nancy 1, 1997. http://www.theses.fr/1997NAN10250.
This work deals with the identification of multivariable systems by the subspace methods (4SID : Subspace-based State-Space System IDentification). The first chapter presents an overview of the existing subspace-based techniques. To complete this theoretical synthesis, the applicability of these approaches is considered in the second chapter. The latter is based on a comparative study between the 4SID algorithms and those of the prediction error method, and is turned on the ill-conditionned multivariable systems. The development of the subspace methods to the identification problem of continuous-time state-space models is presented in the third chapter. A methodology and an algorithm based on the combination of the 4SID algorithms with the Poisson moment functionals filtering are proposed. The last chapter is devoted to the application of the subspace methods to a winding process. In a first part, discrete-time and continuous-time state-space models have been identified, compared and validated around a local operating point. These models have been used to develop and implement a multivariable controller of the winding tensions based on a LQG strategy. In a second part, a semi-physical modeling methodology including subspace methods is proposed and applied to the system in order to determine a simulation grey-box model valid on the whole winding processing. In the last part of this thesis, solutions to the identification problem associated with the asymetric behaviors of the winding tensions are proposed. They are based on the use of piecewise linear models
Gilson, Marion. "Identification des systèmes en boucle fermée : contributions aux méthodes de compensation de biais et des sous-espaces." Nancy 1, 2000. http://www.theses.fr/2000NAN10119.
The thesis deals with closed-loop identification of SISO or MIMO systems, represented by a linear time-invariant-model either in transfer or state-space forms. This work is divided into three main parts. The first part gives key issues associated with closed-loop system identification as well as a bibliographic synthesis of the different available methods, classicall divided into three broad categories and referred to as direct, indirect and joint inout/output approaches. The second part focuses on the so-called bias-eliminated least-squares method for closed-loop identification of a transfer function by an indirect approach. It basically consists in estimating and then removing the bias introduced by the least-squares algorithm. The contribution of this chapter is twofold. At first proposition aims as enlightening the interpretation of those bias eliminated techniques by demonstrating their membership to the instrumental variable estimator class. A second proposition develops an extension of the previous method to the closed-loop continuous-time system identification, from sampled input/output data. Then, the last part of this thesis adresses the crucial (open) point of analyzing and assessing the quality of a nominal closed-loop state-space model stemmed from a subspace technique. In this respect, the identification algorithm is formulated in terms of a criterion minimisaton. This formulation is used on the one hand, to develop an algorithm improvement for estimating the nominal model. On the second hand, several methofd for estimating uncertainty regions of nominal model invariant parameters are proposed
Jhinaoui, Ahmed. "Subspace-based identification and vibration monitoring algorithms for rotating systems." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S161.
Subspace identification methods are widely used for caracterizing modal param-eters and for vibration monitoring of mechanical structures. They were shown powerful for the so-called linear time-invariant systems. However, they are not adapted to rotating sys-tems such as helicopters and wind turbines, which are inherently time-periodic systems. The goal of this thesis is to extend the applicability of these methods to this particular class of systems. First, a new identification algorithm is suggested. This algorithm permits to iden-tify the so-called Floquet modal structure. Then, a sensitivity study is conducted in order to quantify uncertainties, related to noises and other sources, about the identified modal param-eters. Finally and based on the suggested identification algorithm, a method for instability detection is developed. The main feature of this method is to define some residual, which is function of modal parameters, then to detect an eventual change over it which means a possible deviation toward an unstable regime. The suggested methods were applied to both numerical and experimental data
Jorajuria, Corentin. "Estimation de l'amortissement des aubages en analyse modale opérationnelle." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0003.
European goals to reduce air traffic environmental impacts leads to design new civilian turbojet engines. These new designs can result in more severe aeroelastic risks for turbojet engines. In this regard, understanding and predicting dissipation phenomena is a key industrial challenge. As these phenomena can be very wide and complex, experimental approaches take an important role to understand damping. This thesis focuses on the estimation of damping of fan of civilian turbojet engines. To this end, estimation methods in frequency and time domain have been studied. The estimation issues are addressed thanks to a test rig making possible to measure vibratory responses of rotating full-scale fan in vacuum conditions using piezoelectric excitations. Moreover, subspace identification methods, showing particular advantages for the estimation of modes of rotating fans, have been investigated more specifically. Estimation performances of these techniques have been assessed over numerical models. Then, these techniques have been applied over vibratory measurements of a rotating fan in vacuum conditions. Furthermore, experimental data of fans in operation show that excitations can induce significant transient responses. Accordingly, an experimental study evaluating the effect of unsteady responses over modal characterization has been carried out. This experimental study has been performed thanks to modal tests using excitations with different unsteady rate. Finally, estimation methods showing encouraging results over modal tests of a rotating fan in vacuum conditions have been applied over experimental data obtained in operational conditions
Demourant, Fabrice. "Interactions identification-commande robuste : méthodes et applications à l'avion souple." École nationale supérieure de l'aéronautique et de l'espace (Toulouse ; 1972-2007), 2002. http://www.theses.fr/2002ESAE0019.
Mendoume, Minko Ignace Davy. "Identification des systèmes dynamiques stochastiques." Phd thesis, Clermont-Ferrand 2, 2005. https://tel.archives-ouvertes.fr/tel-00676619/document.
Vincent, Emmanuel. "Modèles d'instruments pour la séparation de sources et la transcription d'enregistrements musicaux." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00544710.
Gautier, Guillaume. "Diagnostic vibratoire des systèmes mécaniques par subspace fitting." Thesis, Tours, 2015. http://www.theses.fr/2015TOUR4026/document.
In this thesis, a subspace fitting (SF) method is presented for the identification of mechanical parameters and assessment of the health condition of vibrating structures. The SF method attempts to extract, from subspace identification methods (4SID), a system observability matrix of the system and correlate them with a theoretical observability matrix. The originality of this work is to obtain the theoretical observability matrix from a finite element model (EF) of the structure. By adjusting unknown parameters of the FE model, the mechanical properties of the vibrating structure are identified. Computational costs of such a procedure are reduced by considering a model reduction method based on the excitations and sensors location. The method is evaluated for the identification of natural frequencies of a vibrating structure. Numerical and experimental applications are assessed to show the relevance of such an approach. In particular, it is highlighted that the SF method can accurately identify the natural frequencies of a structure to high noise levels
Saeed, Kashif. "CONTRIBUTION A LA SURVEILLANCE DE L'INTEGRITE DES STRUCTURES." Phd thesis, 2010. http://pastel.archives-ouvertes.fr/pastel-00503109.