Documents disponibles écrits par cet auteur

Adaptive PID cascade control for superheated steam temperature based on inverse model / Zhijie Wang in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 11 (Novembre 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 11 (Novembre 2011) . - 06 P. Titre : Adaptive PID cascade control for superheated steam temperature based on inverse model Type de document : texte imprimé Auteurs : Zhijie Wang, Auteur ; Guangjun Wang, Auteur ; Chen, Hong, Auteur Année de publication : 2012 Article en page(s) : 06 P. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Adaptive  control  Boilers  Fuzzy  control  Power  generation  control  Temperature  control  Thermal  power  stations  Three-term  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Since the superheated steam temperature system of boiler in thermal power plant is characterized as time varying and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional-integral-derivative (PID) cascade control scheme. This paper presents a design method of adaptive PID cascade control system for superheated steam temperature based on inverse model: First, the inner loop and the outer process in the cascade control system are equivalent to a generalized plant. A simplified Takagi–Sugeno (STS) fuzzy model is adopted to identify the inverse model of the generalized plant. By choosing the appropriate structure and optimizing with constrains for the parameters of the inverse model, the organic combination of the PID primary controller with the inverse model is realized. To maintain the structure of the existing conventional PID cascade control system in power plant without change, in the control process, the parameters of the primary controller are adjusted on-line according to the identification result of the inverse model of the generalized plant; thus an adaptive PID cascade control system is formed, which matches with the characteristics of the controlled plant. Through the simulation experiments of controlling superheated steam temperature, it is illustrated that the proposed scheme has good adaptability and anti-interference ability. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Adaptive PID cascade control for superheated steam temperature based on inverse model [texte imprimé] / Zhijie Wang, Auteur ; Guangjun Wang, Auteur ; Chen, Hong, Auteur . - 2012 . - 06 P. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 11 (Novembre 2011) . - 06 P. Mots-clés : Adaptive  control  Boilers  Fuzzy  control  Power  generation  control  Temperature  control  Thermal  power  stations  Three-term  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Since the superheated steam temperature system of boiler in thermal power plant is characterized as time varying and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional-integral-derivative (PID) cascade control scheme. This paper presents a design method of adaptive PID cascade control system for superheated steam temperature based on inverse model: First, the inner loop and the outer process in the cascade control system are equivalent to a generalized plant. A simplified Takagi–Sugeno (STS) fuzzy model is adopted to identify the inverse model of the generalized plant. By choosing the appropriate structure and optimizing with constrains for the parameters of the inverse model, the organic combination of the PID primary controller with the inverse model is realized. To maintain the structure of the existing conventional PID cascade control system in power plant without change, in the control process, the parameters of the primary controller are adjusted on-line according to the identification result of the inverse model of the generalized plant; thus an adaptive PID cascade control system is formed, which matches with the characteristics of the controlled plant. Through the simulation experiments of controlling superheated steam temperature, it is illustrated that the proposed scheme has good adaptability and anti-interference ability. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Explosion and Fire Analysis of Steel Frames Using Mixed Element Approach / Richard Liew, J. Y. in Journal of engineering mechanics, Vol.131, N°6 (Juin 2005) 

Public ISBD [article]  in Journal of engineering mechanics > Vol.131, N°6 (Juin 2005) . - 606-616 p. Titre : Explosion and Fire Analysis of Steel Frames Using Mixed Element Approach Titre original : Analyse d'Explosion et de Feu des Armatures en Acier en Utilisant l'Approche Mélangée d'Elément Type de document : texte imprimé Auteurs : Richard Liew, J. Y., Auteur ; Chen, Hong, Auteur Article en page(s) : 606-616 p. Note générale : Génie Civil, Génie Mécanique Langues : Anglais (eng) Mots-clés : Blast  loads  Transient  loads  Explosions  Fire  resistance  Strain  rate  Buckling  Steel  frames  Charges  de  souffle  Charges  passagères  Explosions  Résistance  de  feu  Boucling  Fléchissement  Taux  de  contrainte  Armatures  en  acier Index. décimale : 621.34/624 Résumé : This Paper presents a mixed element approach for analyzing steel frame structures subjected to a localized explosion and followed by fire. Critical members that are subjected to direct action of explosion and fire are modeled using shell elements. Noncritical members that are away from the affected area are modeled using beam elements. The Proposed approach is computationally efficient for modeling large-scale structures and accurate enough to capture detailed behavior of member inelasticity and stability associated with the effects of blast and fires. Section classification may change from static load because of the enhanced yield strength due to high strain rate. The Beam element approach is found to overpredict the overall resistance of steel frame structures if local deformation of cros section occured after the blast loads. Detailed finite element modeling of critical frame members is necessary to improve the accuracy of predicting the ultimate resistance of structures. The Proposed approach is applied to study the ultimate behaviors of a steel column and a three-story steel frame under explosion and fire. Cet article présente une approche mélangée d'élément pour analyser les structures en acier d'armature soumises à une explosion localisée et suivies du feu. Des membres critiques qui sont soumis à l'action directe de l'explosion et du feu sont modelés en utilisant des éléments de coquille. Des membres de Noncritical qui sont partis du secteur affecté sont modelés en utilisant des éléments de faisceau. L'approche proposée est informatique efficace pour modeler les structures à grande échelle et assez précise pour capturer le comportement détaillé de l'inélasticité et de la stabilité de membre liées aux effets du souffle et des feux. La classification de section peut changer de la charge statique en raison de la force augmentée de rendement due au taux élevé de contrainte. L'approche d'élément de faisceau est trouvée à l'overpredict que la résistance globale de l'armature en acier structure si la déformation locale de la section de cros se produisait après les charges de souffle. Modeler fini détaillé d'élément des membres critiques d'armature est nécessaire pour améliorer l'exactitude de prévoir la résistance finale des structures. L'approche proposée est appliquée pour étudier les comportements finals d'une colonne en acier et d'une armature en acier d'trois-histoire sous l'explosion et le feu. En ligne : cveljy@nus.edu.sg [article] Explosion and Fire Analysis of Steel Frames Using Mixed Element Approach = Analyse d'Explosion et de Feu des Armatures en Acier en Utilisant l'Approche Mélangée d'Elément [texte imprimé] / Richard Liew, J. Y., Auteur ; Chen, Hong, Auteur . - 606-616 p. Génie Civil, Génie Mécanique Langues : Anglais (eng) in Journal of engineering mechanics > Vol.131, N°6 (Juin 2005) . - 606-616 p. Mots-clés : Blast  loads  Transient  loads  Explosions  Fire  resistance  Strain  rate  Buckling  Steel  frames  Charges  de  souffle  Charges  passagères  Explosions  Résistance  de  feu  Boucling  Fléchissement  Taux  de  contrainte  Armatures  en  acier Index. décimale : 621.34/624 Résumé : This Paper presents a mixed element approach for analyzing steel frame structures subjected to a localized explosion and followed by fire. Critical members that are subjected to direct action of explosion and fire are modeled using shell elements. Noncritical members that are away from the affected area are modeled using beam elements. The Proposed approach is computationally efficient for modeling large-scale structures and accurate enough to capture detailed behavior of member inelasticity and stability associated with the effects of blast and fires. Section classification may change from static load because of the enhanced yield strength due to high strain rate. The Beam element approach is found to overpredict the overall resistance of steel frame structures if local deformation of cros section occured after the blast loads. Detailed finite element modeling of critical frame members is necessary to improve the accuracy of predicting the ultimate resistance of structures. The Proposed approach is applied to study the ultimate behaviors of a steel column and a three-story steel frame under explosion and fire. Cet article présente une approche mélangée d'élément pour analyser les structures en acier d'armature soumises à une explosion localisée et suivies du feu. Des membres critiques qui sont soumis à l'action directe de l'explosion et du feu sont modelés en utilisant des éléments de coquille. Des membres de Noncritical qui sont partis du secteur affecté sont modelés en utilisant des éléments de faisceau. L'approche proposée est informatique efficace pour modeler les structures à grande échelle et assez précise pour capturer le comportement détaillé de l'inélasticité et de la stabilité de membre liées aux effets du souffle et des feux. La classification de section peut changer de la charge statique en raison de la force augmentée de rendement due au taux élevé de contrainte. L'approche d'élément de faisceau est trouvée à l'overpredict que la résistance globale de l'armature en acier structure si la déformation locale de la section de cros se produisait après les charges de souffle. Modeler fini détaillé d'élément des membres critiques d'armature est nécessaire pour améliorer l'exactitude de prévoir la résistance finale des structures. L'approche proposée est appliquée pour étudier les comportements finals d'une colonne en acier et d'une armature en acier d'trois-histoire sous l'explosion et le feu. En ligne : cveljy@nus.edu.sg

Inverse estimation for heat flux distribution at the metal-mold interface using fuzzy inference / Lina Zhu in Journal of heat transfer, Vol. 133 N° 8 (Août 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 8 (Août 2011) . - pp. [081602/1-6] Titre : Inverse estimation for heat flux distribution at the metal-mold interface using fuzzy inference Type de document : texte imprimé Auteurs : Lina Zhu, Auteur ; Guangjun Wang, Auteur ; Chen, Hong, Auteur Année de publication : 2011 Article en page(s) : pp. [081602/1-6] Note générale : Physique Langues : Anglais (eng) Mots-clés : Inverse  approach  Fuzzy  inference  Heat  flux  distribution  Continuous  casting Index. décimale : 536 Chaleur. Thermodynamique Résumé : This study provides a new inverse approach based on fuzzy inference for solving the problem of estimating heat flux distribution at the metal-mold interface in the continuous casting process. Measured temperatures acquired with the thermocouples buried in the mold are used to obtain corresponding inference results with the fuzzy inference. Then according to the importance of measured information for estimating the heat flux distribution, inference results are weighted to realize estimation of heat flux distribution at the metal-mold interface. Some numerical tests are presented to discuss the validity of the present approach by using different initial guesses of heat flux distribution, the number of measuring points, and measurement errors. In comparison with the conjugate gradient method, it is concluded that the method based on fuzzy inference is of a good anti-ill-posed characteristic. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...] [article] Inverse estimation for heat flux distribution at the metal-mold interface using fuzzy inference [texte imprimé] / Lina Zhu, Auteur ; Guangjun Wang, Auteur ; Chen, Hong, Auteur . - 2011 . - pp. [081602/1-6]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 8 (Août 2011) . - pp. [081602/1-6] Mots-clés : Inverse  approach  Fuzzy  inference  Heat  flux  distribution  Continuous  casting Index. décimale : 536 Chaleur. Thermodynamique Résumé : This study provides a new inverse approach based on fuzzy inference for solving the problem of estimating heat flux distribution at the metal-mold interface in the continuous casting process. Measured temperatures acquired with the thermocouples buried in the mold are used to obtain corresponding inference results with the fuzzy inference. Then according to the importance of measured information for estimating the heat flux distribution, inference results are weighted to realize estimation of heat flux distribution at the metal-mold interface. Some numerical tests are presented to discuss the validity of the present approach by using different initial guesses of heat flux distribution, the number of measuring points, and measurement errors. In comparison with the conjugate gradient method, it is concluded that the method based on fuzzy inference is of a good anti-ill-posed characteristic. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013300 [...]

A nonlinear clutch pressure observer for automatic transmission / Bingzhao Gao in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 134 N° 1 (Janvier 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 1 (Janvier 2012) . - 08 p. Titre : A nonlinear clutch pressure observer for automatic transmission : considering drive-shaft compliance Type de document : texte imprimé Auteurs : Bingzhao Gao, Auteur ; Chen, Hong, Auteur ; Lu Tian, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : Dynamic systems Langues : Anglais (eng) Mots-clés : Clutches  Drives  Engines  Nonlinear  control  systems  Observers  Power  transmission  (mechanical)  Reduced  order  systems  Shafts Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : For a new kind of automatic transmissions adopting clutch-to-clutch shift control technology, a clutch pressure observer is proposed to improve the estimation accuracy during the shift torque phase. The observer is designed in the concept of input-to-state stability. Lookup tables, which are widely used to represent the complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer, and the torsional stiffness of the drive axle shaft is considered in the model-based design procedure to improve the estimation accuracy. Finally, the designed pressure observer is tested on an amesim powertrain simulation model. Comparisons with an observer without considering the drive shaft compliance are given as well. DEWEY : 553 ISSN : 0022-0434 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013400 [...] [article] A nonlinear clutch pressure observer for automatic transmission : considering drive-shaft compliance [texte imprimé] / Bingzhao Gao, Auteur ; Chen, Hong, Auteur ; Lu Tian, Auteur . - 2012 . - 08 p. Dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 1 (Janvier 2012) . - 08 p. Mots-clés : Clutches  Drives  Engines  Nonlinear  control  systems  Observers  Power  transmission  (mechanical)  Reduced  order  systems  Shafts Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : For a new kind of automatic transmissions adopting clutch-to-clutch shift control technology, a clutch pressure observer is proposed to improve the estimation accuracy during the shift torque phase. The observer is designed in the concept of input-to-state stability. Lookup tables, which are widely used to represent the complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer, and the torsional stiffness of the drive axle shaft is considered in the model-based design procedure to improve the estimation accuracy. Finally, the designed pressure observer is tested on an amesim powertrain simulation model. Comparisons with an observer without considering the drive shaft compliance are given as well. DEWEY : 553 ISSN : 0022-0434 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013400 [...]

Optimal control and equilibrium behavior of production-inventory systems / Owen Q. Wu in Management science, Vol. 56 N° 8 (Août 2010) 

Public ISBD [article]  in Management science > Vol. 56 N° 8 (Août 2010) . - pp. 1362-1379 Titre : Optimal control and equilibrium behavior of production-inventory systems Type de document : texte imprimé Auteurs : Owen Q. Wu, Auteur ; Chen, Hong, Auteur Année de publication : 2010 Article en page(s) : pp. 1362-1379 Note générale : Management Langues : Anglais (eng) Mots-clés : Optimal  control  Production-inventory  system  Rational  expectations  equilibrium  Petroleum  industry Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : The relationship between commodity inventory and short-term price variations has received considerable attention, but the understanding has been limited to single-stage cross-sectional relation. In this paper, we aim to deepen our understanding of the inventory–price relationship in two dimensions: across time and across production stages. We first examine an individual firm controlling production and two stages of inventory under uncertain input and output prices and operating costs. We next establish and characterize the rational expectations equilibrium for an economy in which competitive production firms link a raw material market and a finished goods market, with uncertain and price-sensitive supply and demand. We characterize the dynamics of inventory, market price, and gross margin based on theoretical analysis, simulation, and empirical evidence from the petroleum industry. We find that inventory fluctuations lag behind price variations, and the length of the lags depend on how far the inventory is from the source of the supply or demand shocks. We also find that shocks are both dampened and delayed when propagating through the production stages, and that shocks have a prolonged effect on inventories and prices at both stages. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/56/8.toc [article] Optimal control and equilibrium behavior of production-inventory systems [texte imprimé] / Owen Q. Wu, Auteur ; Chen, Hong, Auteur . - 2010 . - pp. 1362-1379. Management Langues : Anglais (eng) in Management science > Vol. 56 N° 8 (Août 2010) . - pp. 1362-1379 Mots-clés : Optimal  control  Production-inventory  system  Rational  expectations  equilibrium  Petroleum  industry Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : The relationship between commodity inventory and short-term price variations has received considerable attention, but the understanding has been limited to single-stage cross-sectional relation. In this paper, we aim to deepen our understanding of the inventory–price relationship in two dimensions: across time and across production stages. We first examine an individual firm controlling production and two stages of inventory under uncertain input and output prices and operating costs. We next establish and characterize the rational expectations equilibrium for an economy in which competitive production firms link a raw material market and a finished goods market, with uncertain and price-sensitive supply and demand. We characterize the dynamics of inventory, market price, and gross margin based on theoretical analysis, simulation, and empirical evidence from the petroleum industry. We find that inventory fluctuations lag behind price variations, and the length of the lags depend on how far the inventory is from the source of the supply or demand shocks. We also find that shocks are both dampened and delayed when propagating through the production stages, and that shocks have a prolonged effect on inventories and prices at both stages. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/56/8.toc

A Reduced-order nonlinear clutch pressure observer for automatic transmission / Bingzhao Gao in IEEE Transactions on control systems technology, Vol. 18 N° 2 (Mars 2010) 

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