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Effective tuning method for fuzzy PID with internal model control / X. Duan in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8317–8323 Titre : Effective tuning method for fuzzy PID with internal model control Type de document : texte imprimé Auteurs : X. Duan, Auteur ; Han-Xiong Li, Auteur Année de publication : 2008 Article en page(s) : p. 8317–8323 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : The  lyapunov  stability  theory Résumé : An internal model control (IMC) based tuning method is proposed to autotune the fuzzy proportional integral derivative (PID) controller in this paper. An analytical model of the fuzzy PID controller is first derived, which consists of a linear PID controller and a nonlinear compensation item. The nonlinear compensation item can be considered as a process disturbance, and then parameters of the fuzzy PID controller can be analytically determined on the basis of the IMC structure. The stability of the fuzzy PID control system is analyzed using the Lyapunov stability theory. The simulation results demonstrate the effectiveness of the proposed tuning method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800485j [article] Effective tuning method for fuzzy PID with internal model control [texte imprimé] / X. Duan, Auteur ; Han-Xiong Li, Auteur . - 2008 . - p. 8317–8323. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8317–8323 Mots-clés : The  lyapunov  stability  theory Résumé : An internal model control (IMC) based tuning method is proposed to autotune the fuzzy proportional integral derivative (PID) controller in this paper. An analytical model of the fuzzy PID controller is first derived, which consists of a linear PID controller and a nonlinear compensation item. The nonlinear compensation item can be considered as a process disturbance, and then parameters of the fuzzy PID controller can be analytically determined on the basis of the IMC structure. The stability of the fuzzy PID control system is analyzed using the Lyapunov stability theory. The simulation results demonstrate the effectiveness of the proposed tuning method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800485j

Thermal protection of a ground layer with phase change materials / X. Duan in Journal of heat transfer, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 1 (Janvier 2010) . - pp. [011301/9] Titre : Thermal protection of a ground layer with phase change materials Type de document : texte imprimé Auteurs : X. Duan, Auteur ; G. F. Naterer, Auteur Article en page(s) : pp. [011301/9] Note générale : Physique Langues : Anglais (eng) Mots-clés : Phase  change  material  Ground  heat  transfer  Insulation  Foundation  Permafrost Index. décimale : 536 Chaleur. Thermodynamique Résumé : Conventional ground surface insulation can be used to protect power line foundations in permafrost regions from the adverse effects of seasonal freezing and thawing cycles. But previous studies have shown ineffective thermal protection against the receding permafrost with conventional insulation. In this paper, an alternative thermal protection method (phase change materials (PCMs)) is analyzed and studied experimentally. Seasonal ground temperature variations are estimated by an analytical conduction model, with a sinusoidal ground surface temperature variation. A compensation function is introduced to predict temperature variations in the foundation, when the ground surface reaches a certain temperature profile. Measured data are acquired from an experimental test cell to simulate the tower foundation. With thermal energy storage in the PCM layer, the surface temperature of the soil was modified, leading to changes in temperature in the foundation. Measured temperature data show that the PCM thermal barrier effectively reduces the temperature variation amplitude in the foundation, thereby alleviating the seasonal freezing and thawing cycles. Different thermal effects of the PCM thermal barrier were obtained under different air temperature conditions. These are analyzed via melting degree hours and freezing degree hours, compared with a critical number of degree hours. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Thermal protection of a ground layer with phase change materials [texte imprimé] / X. Duan, Auteur ; G. F. Naterer, Auteur . - pp. [011301/9]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 1 (Janvier 2010) . - pp. [011301/9] Mots-clés : Phase  change  material  Ground  heat  transfer  Insulation  Foundation  Permafrost Index. décimale : 536 Chaleur. Thermodynamique Résumé : Conventional ground surface insulation can be used to protect power line foundations in permafrost regions from the adverse effects of seasonal freezing and thawing cycles. But previous studies have shown ineffective thermal protection against the receding permafrost with conventional insulation. In this paper, an alternative thermal protection method (phase change materials (PCMs)) is analyzed and studied experimentally. Seasonal ground temperature variations are estimated by an analytical conduction model, with a sinusoidal ground surface temperature variation. A compensation function is introduced to predict temperature variations in the foundation, when the ground surface reaches a certain temperature profile. Measured data are acquired from an experimental test cell to simulate the tower foundation. With thermal energy storage in the PCM layer, the surface temperature of the soil was modified, leading to changes in temperature in the foundation. Measured temperature data show that the PCM thermal barrier effectively reduces the temperature variation amplitude in the foundation, thereby alleviating the seasonal freezing and thawing cycles. Different thermal effects of the PCM thermal barrier were obtained under different air temperature conditions. These are analyzed via melting degree hours and freezing degree hours, compared with a critical number of degree hours. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]