Documents disponibles écrits par cet auteur

Realization-preserving structure and order reduction of nonlinear energetic system models using energy trajectory correlations / Tulga Ersal in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 3 (Mai 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 3 (Mai 2009) . - 08 p. Titre : Realization-preserving structure and order reduction of nonlinear energetic system models using energy trajectory correlations Type de document : texte imprimé Auteurs : Tulga Ersal, Auteur ; Hosam K. Fathy, Auteur ; Jeffrey L. Stein, Auteur Année de publication : 2009 Article en page(s) : 08 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : lumped  dynamic  system  model;  new  energy-based  metric;  correlation;  energy  flow  pattern;  Karhunen–Loève  expansion Résumé : Previous work by the authors developed algorithms for simplifying the structure of a lumped dynamic system model and reducing its order. This paper extends this previous work to enable simultaneous model structure and order reduction. Specifically, it introduces a new energy-based metric to evaluate the relative importance of energetic connections in a model. This metric (1) accounts for correlations between energy flow patterns in a model using the Karhunen–Loève expansion; (2) examines all energetic connections in a model, thereby assessing the relative importance of both energetic components and their interactions, and enabling both order and structural reduction; and (3) is realization preserving, in the sense of not requiring a state transformation. A reduction scheme based on this metric is presented and illustrated using a simple example. The example shows that the proposed method can successfully concurrently reduce model order and structure without requiring a realization change, and that it can provide an improved assessment of the importance of various model components due to its correlation-based nature. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Realization-preserving structure and order reduction of nonlinear energetic system models using energy trajectory correlations [texte imprimé] / Tulga Ersal, Auteur ; Hosam K. Fathy, Auteur ; Jeffrey L. Stein, Auteur . - 2009 . - 08 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 3 (Mai 2009) . - 08 p. Mots-clés : lumped  dynamic  system  model;  new  energy-based  metric;  correlation;  energy  flow  pattern;  Karhunen–Loève  expansion Résumé : Previous work by the authors developed algorithms for simplifying the structure of a lumped dynamic system model and reducing its order. This paper extends this previous work to enable simultaneous model structure and order reduction. Specifically, it introduces a new energy-based metric to evaluate the relative importance of energetic connections in a model. This metric (1) accounts for correlations between energy flow patterns in a model using the Karhunen–Loève expansion; (2) examines all energetic connections in a model, thereby assessing the relative importance of both energetic components and their interactions, and enabling both order and structural reduction; and (3) is realization preserving, in the sense of not requiring a state transformation. A reduction scheme based on this metric is presented and illustrated using a simple example. The example shows that the proposed method can successfully concurrently reduce model order and structure without requiring a realization change, and that it can provide an improved assessment of the importance of various model components due to its correlation-based nature. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

A review of proper modeling techniques / Tulga Ersal in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°6 (Novembre 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°6 (Novembre 2008) . - 13 p. Titre : A review of proper modeling techniques Type de document : texte imprimé Auteurs : Tulga Ersal, Auteur ; D. Geoff Rideout, Auteur ; Loucas S. Louca, Auteur Année de publication : 2009 Article en page(s) : 13 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : algorithms;  modeling;  approximation;  dynamics  (mechanics);  optimization;  errors;  dynamic  systems Résumé : A dynamic system model is proper for a particular application if it achieves the accuracy required by the application with minimal complexity. Because model complexity often—but not always—correlates inversely with simulation speed, a proper model is often alternatively defined as one balancing accuracy and speed. Such balancing is crucial for applications requiring both model accuracy and speed, such as system optimization and hardware-in-the-loop simulation. Furthermore, the simplicity of proper models conduces to control system analysis and design, particularly given the ease with which lower-order controllers can be implemented compared to higher-order ones. The literature presents many algorithms for deducing proper models from simpler ones or reducing complex models until they become proper. This paper presents a broad survey of the proper modeling literature. To simplify the presentation, the algorithms are classified into frequency, projection, optimization, and energy based, based on the metrics they use for obtaining proper models. The basic mechanics, properties, advantages, and limitations of the methods are discussed, along with the relationships between different techniques, with the intention of helping the modeler to identify the most suitable proper modeling method for a given application. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] A review of proper modeling techniques [texte imprimé] / Tulga Ersal, Auteur ; D. Geoff Rideout, Auteur ; Loucas S. Louca, Auteur . - 2009 . - 13 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°6 (Novembre 2008) . - 13 p. Mots-clés : algorithms;  modeling;  approximation;  dynamics  (mechanics);  optimization;  errors;  dynamic  systems Résumé : A dynamic system model is proper for a particular application if it achieves the accuracy required by the application with minimal complexity. Because model complexity often—but not always—correlates inversely with simulation speed, a proper model is often alternatively defined as one balancing accuracy and speed. Such balancing is crucial for applications requiring both model accuracy and speed, such as system optimization and hardware-in-the-loop simulation. Furthermore, the simplicity of proper models conduces to control system analysis and design, particularly given the ease with which lower-order controllers can be implemented compared to higher-order ones. The literature presents many algorithms for deducing proper models from simpler ones or reducing complex models until they become proper. This paper presents a broad survey of the proper modeling literature. To simplify the presentation, the algorithms are classified into frequency, projection, optimization, and energy based, based on the metrics they use for obtaining proper models. The basic mechanics, properties, advantages, and limitations of the methods are discussed, along with the relationships between different techniques, with the intention of helping the modeler to identify the most suitable proper modeling method for a given application. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]