Documents disponibles écrits par cet auteur

Consensus tracking under directed interaction topologies / Wei Ren in IEEE Transactions on control systems technology, Vol. 18 N° 1 (Janvier 2010) 

Public ISBD [article]  in IEEE Transactions on control systems technology > Vol. 18 N° 1 (Janvier 2010) . - pp. 230-237 Titre : Consensus tracking under directed interaction topologies : algorithms and experiments Type de document : texte imprimé Auteurs : Wei Ren, Auteur Année de publication : 2011 Article en page(s) : pp. 230-237 Note générale : Génie Aérospatial Langues : Anglais (eng) Mots-clés : Consensus  Cooperative  control  Formation  control  Multi-vehicle  systems Index. décimale : 629.1 Résumé : Consensus tracking problems with, respectively, bounded control effort and directed switching interaction topologies are considered when a time-varying consensus reference state is available to only a subgroup of a team and the team members have only local interaction. A consensus tracking algorithm explicitly accounting for bounded control effort is proposed and analyzed under a directed fixed interaction topology. Furthermore, convergence analysis for a consensus tracking algorithm is provided when the time-varying consensus reference state is available to a dynamically changing subgroup of the team under directed switching inter-vehicle interaction topologies. Experimental results of a formation control application are demonstrated on a multi-robot platform to validate one of the proposed consensus tracking algorithms. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5229136 [article] Consensus tracking under directed interaction topologies : algorithms and experiments [texte imprimé] / Wei Ren, Auteur . - 2011 . - pp. 230-237. Génie Aérospatial Langues : Anglais (eng) in IEEE Transactions on control systems technology > Vol. 18 N° 1 (Janvier 2010) . - pp. 230-237 Mots-clés : Consensus  Cooperative  control  Formation  control  Multi-vehicle  systems Index. décimale : 629.1 Résumé : Consensus tracking problems with, respectively, bounded control effort and directed switching interaction topologies are considered when a time-varying consensus reference state is available to only a subgroup of a team and the team members have only local interaction. A consensus tracking algorithm explicitly accounting for bounded control effort is proposed and analyzed under a directed fixed interaction topology. Furthermore, convergence analysis for a consensus tracking algorithm is provided when the time-varying consensus reference state is available to a dynamically changing subgroup of the team under directed switching inter-vehicle interaction topologies. Experimental results of a formation control application are demonstrated on a multi-robot platform to validate one of the proposed consensus tracking algorithms. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5229136

Distributed cooperative attitude synchronization and tracking for multiple rigid bodies / Wei Ren in IEEE Transactions on control systems technology, Vol. 18 N° 2 (Mars 2010) 

Public ISBD [article]  in IEEE Transactions on control systems technology > Vol. 18 N° 2 (Mars 2010) . - pp. 383-392 Titre : Distributed cooperative attitude synchronization and tracking for multiple rigid bodies Type de document : texte imprimé Auteurs : Wei Ren, Auteur Année de publication : 2011 Article en page(s) : pp. 383-392 Note générale : Génie Aérospatial Langues : Anglais (eng) Mots-clés : Attitude  synchronization  Cooperative  control  Distributed  algorithms  Multi-vehicule  systems Index. décimale : 629.1 Résumé : In this paper, distributed cooperative attitude synchronization and tracking problems are considered for multiple rigid bodies with attitudes represented by modified rodriguez parameters. Two distributed control laws are proposed and analyzed. The first control law applies a passivity approach for distributed attitude synchronization. The control law guarantees attitude synchronization without the requirement for absolute angular velocity measurements and relative angular velocity measurements between neighboring rigid bodies. The second control law incorporates a time-varying reference attitude, where the reference attitude is allowed to be available to only a subset of the group members under general directed information exchange. The control law guarantees that all rigid bodies track the time-varying reference attitude as long as a virtual leader whose attitude is the time-varying reference attitude has a directed path to all other rigid bodies in the group. Simulation results are presented to demonstrate the effectiveness of the two control laws. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5229134 [article] Distributed cooperative attitude synchronization and tracking for multiple rigid bodies [texte imprimé] / Wei Ren, Auteur . - 2011 . - pp. 383-392. Génie Aérospatial Langues : Anglais (eng) in IEEE Transactions on control systems technology > Vol. 18 N° 2 (Mars 2010) . - pp. 383-392 Mots-clés : Attitude  synchronization  Cooperative  control  Distributed  algorithms  Multi-vehicule  systems Index. décimale : 629.1 Résumé : In this paper, distributed cooperative attitude synchronization and tracking problems are considered for multiple rigid bodies with attitudes represented by modified rodriguez parameters. Two distributed control laws are proposed and analyzed. The first control law applies a passivity approach for distributed attitude synchronization. The control law guarantees attitude synchronization without the requirement for absolute angular velocity measurements and relative angular velocity measurements between neighboring rigid bodies. The second control law incorporates a time-varying reference attitude, where the reference attitude is allowed to be available to only a subset of the group members under general directed information exchange. The control law guarantees that all rigid bodies track the time-varying reference attitude as long as a virtual leader whose attitude is the time-varying reference attitude has a directed path to all other rigid bodies in the group. Simulation results are presented to demonstrate the effectiveness of the two control laws. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5229134

Understanding biphasic ionic liquid/CO2 systems for homogeneous catalysis / Azita Ahosseini in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4254–4265 Titre : Understanding biphasic ionic liquid/CO2 systems for homogeneous catalysis : hydroformylation Type de document : texte imprimé Auteurs : Azita Ahosseini, Auteur ; Wei Ren, Auteur ; Aaron M. Scurto, Auteur Année de publication : 2009 Article en page(s) : pp. 4254–4265 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Biphasic  ionic  liquid  Compressed  carbon  dioxide  system  Homogeneous  catalysis  Hydroformylation Résumé : A biphasic ionic liquid (IL) and compressed carbon dioxide system has a number of advantages for efficient homogeneous catalysis. The hydroformylation of 1-octene to nonanal catalyzed by a rhodium−triphenylphosphine complex was used as a model reaction to illustrate the effects of carbon dioxide in a biphasic ionic liquid/CO2 system using the model ionic liquid, 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)amide ([HMIm][Tf2N]). Detailed phase equilibrium studies were conducted to determine volume expansion of the IL phase and the multiphase equilibria and mixture critical points between the reactant, product, and IL with CO2 and syngas (CO/H2). These data ultimately affect the concentration of the reactant and, thus, the apparent reaction rate. The viscosity of the IL with CO2 pressure was measured and demonstrates the dramatic decrease with increasing CO2 pressure. The self-diffusion coefficient of the ionic liquid and 1-octene were measured and indicate a large increase with CO2 pressure (solubility). With an understanding of the kinetics, phase behavior, and mass transport, biphasic IL/CO2 reaction systems may be properly understood and designed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801871k [article] Understanding biphasic ionic liquid/CO2 systems for homogeneous catalysis : hydroformylation [texte imprimé] / Azita Ahosseini, Auteur ; Wei Ren, Auteur ; Aaron M. Scurto, Auteur . - 2009 . - pp. 4254–4265. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4254–4265 Mots-clés : Biphasic  ionic  liquid  Compressed  carbon  dioxide  system  Homogeneous  catalysis  Hydroformylation Résumé : A biphasic ionic liquid (IL) and compressed carbon dioxide system has a number of advantages for efficient homogeneous catalysis. The hydroformylation of 1-octene to nonanal catalyzed by a rhodium−triphenylphosphine complex was used as a model reaction to illustrate the effects of carbon dioxide in a biphasic ionic liquid/CO2 system using the model ionic liquid, 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)amide ([HMIm][Tf2N]). Detailed phase equilibrium studies were conducted to determine volume expansion of the IL phase and the multiphase equilibria and mixture critical points between the reactant, product, and IL with CO2 and syngas (CO/H2). These data ultimately affect the concentration of the reactant and, thus, the apparent reaction rate. The viscosity of the IL with CO2 pressure was measured and demonstrates the dramatic decrease with increasing CO2 pressure. The self-diffusion coefficient of the ionic liquid and 1-octene were measured and indicate a large increase with CO2 pressure (solubility). With an understanding of the kinetics, phase behavior, and mass transport, biphasic IL/CO2 reaction systems may be properly understood and designed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801871k