Documents disponibles écrits par cet auteur

Quantitative fault tolerant control design for a leaking hydraulic actuator / Mark Karpenko in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 132 N° 5 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 5 (Septembre 2010) . - 07 p. Titre : Quantitative fault tolerant control design for a leaking hydraulic actuator Type de document : texte imprimé Auteurs : Mark Karpenko, Auteur ; Sepehri, Nariman, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Systèmes dynamiques Langues : Anglais (eng) Mots-clés : Closed  loop  systems  Control  system  synthesis  Controllers  Fault  tolerance  Feedback  Fourier  transforms  Gain  control  Hydraulic  actuators  Position  control  Robust  control Index. décimale : 629.8 Résumé : This paper documents the design of a low-order, fixed-gain, controller that can maintain the positioning performance of an electrohydraulic actuator operating under variable load with a leaking piston seal. A set of linear time-invariant equivalent models of the faulty hydraulic actuator is first established, in the frequency domain, by Fourier transformation of acceptable actuator input-output responses. Then, a robust position control law is synthesized by quantitative feedback theory to meet the prescribed design tolerances on closed-loop stability and reference tracking. The designed fault tolerant controller uses only actuator position as feedback, yet it can accommodate nonlinearities in the hydraulic functions, maintain robustness against typical parametric uncertainties, and maintain the closed-loop performance despite a leakage fault that can bypass up to 40% of the rated servovalve flow across the actuator piston. To demonstrate the utility of the fault tolerant control approach in a realistic application, the experimental fault tolerant hydraulic system is operated as a flight surface actuator in the hardware-in-the-loop simulation of a high-performance jet aircraft. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...] [article] Quantitative fault tolerant control design for a leaking hydraulic actuator [texte imprimé] / Mark Karpenko, Auteur ; Sepehri, Nariman, Auteur . - 2010 . - 07 p. Systèmes dynamiques Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 5 (Septembre 2010) . - 07 p. Mots-clés : Closed  loop  systems  Control  system  synthesis  Controllers  Fault  tolerance  Feedback  Fourier  transforms  Gain  control  Hydraulic  actuators  Position  control  Robust  control Index. décimale : 629.8 Résumé : This paper documents the design of a low-order, fixed-gain, controller that can maintain the positioning performance of an electrohydraulic actuator operating under variable load with a leaking piston seal. A set of linear time-invariant equivalent models of the faulty hydraulic actuator is first established, in the frequency domain, by Fourier transformation of acceptable actuator input-output responses. Then, a robust position control law is synthesized by quantitative feedback theory to meet the prescribed design tolerances on closed-loop stability and reference tracking. The designed fault tolerant controller uses only actuator position as feedback, yet it can accommodate nonlinearities in the hydraulic functions, maintain robustness against typical parametric uncertainties, and maintain the closed-loop performance despite a leakage fault that can bypass up to 40% of the rated servovalve flow across the actuator piston. To demonstrate the utility of the fault tolerant control approach in a realistic application, the experimental fault tolerant hydraulic system is operated as a flight surface actuator in the hardware-in-the-loop simulation of a high-performance jet aircraft. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...]

Tracking control of hydraulic actuators using a LuGre friction model compensation / Hairong Zeng in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 N°1 (Janvier/Fevrier 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N°1 (Janvier/Fevrier 2008) . - 7 p. Titre : Tracking control of hydraulic actuators using a LuGre friction model compensation Type de document : texte imprimé Auteurs : Hairong Zeng, Auteur ; Sepehri, Nariman, Auteur Année de publication : 2008 Article en page(s) : 7 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : hydraulic  actuators;  robotic  systems;  tracking  control Résumé : This paper addresses the tracking control of hydraulic actuators commonly used in many hydraulically actuated robotic systems. Dynamic model of the entire actuator incorporating highly nonlinear hydraulic functions and the LuGre dynamic friction model is used to arrive at a suitable controller. The controller is augmented with adaptation laws to compensate for parametric uncertainties in the actuator dynamics, hydraulic functions as well as friction with nonuniform force variations. Furthermore, an adaptive observer is used in the controller to avoid the use of acceleration measurement. Therefore, only measurements of displacement, velocity, and hydraulic line pressures are required for the implementation of the proposed controller. Stability and convergence of the control system are theoretically studied. Experimental results are presented verifying the effectiveness of the developed controller. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Tracking control of hydraulic actuators using a LuGre friction model compensation [texte imprimé] / Hairong Zeng, Auteur ; Sepehri, Nariman, Auteur . - 2008 . - 7 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N°1 (Janvier/Fevrier 2008) . - 7 p. Mots-clés : hydraulic  actuators;  robotic  systems;  tracking  control Résumé : This paper addresses the tracking control of hydraulic actuators commonly used in many hydraulically actuated robotic systems. Dynamic model of the entire actuator incorporating highly nonlinear hydraulic functions and the LuGre dynamic friction model is used to arrive at a suitable controller. The controller is augmented with adaptation laws to compensate for parametric uncertainties in the actuator dynamics, hydraulic functions as well as friction with nonuniform force variations. Furthermore, an adaptive observer is used in the controller to avoid the use of acceleration measurement. Therefore, only measurements of displacement, velocity, and hydraulic line pressures are required for the implementation of the proposed controller. Stability and convergence of the control system are theoretically studied. Experimental results are presented verifying the effectiveness of the developed controller. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

A wavelet-based approach to internal seal damage diagnosis in hydraulic actuators / Goharrizi, Amin Yazdanpanah in IEEE transactions on industrial electronics, Vol. 57 N° 5 (Mai 2010) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 57 N° 5 (Mai 2010) . - pp. 1755 - 1763 Titre : A wavelet-based approach to internal seal damage diagnosis in hydraulic actuators Type de document : texte imprimé Auteurs : Goharrizi, Amin Yazdanpanah, Auteur ; Sepehri, Nariman, Auteur Année de publication : 2011 Article en page(s) : pp. 1755 - 1763 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Fault  detection  Hydraulic  actuators  Internal  leakage  Wavelet  transform  (WT) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : This paper describes the application of wavelet transform (WT) to detect internal leakage in hydraulic actuators, caused by seal damage. The method analyzes the pressure signal at one side of the actuator in response to periodic step inputs to the control valve. It is shown that the detailed version of decomposed pressure signal, using discrete WT, establishes feature patterns that can effectively detect internal leakage and its severity. The proposed scheme requires a baseline (threshold) value, predetermined first by analyzing the pressure signal of a healthy actuator. Once the root mean square (rms) of the level-two detail coefficient values, obtained from the measured pressure signals in subsequent offline tests, fall below this baseline, a fault alarm is triggered. Furthermore, the degree of changes of the rms value from the one obtained under normal operating condition indicates the severity of fault. Experimental tests show promising results for detecting internal leakages as low as 0.124 L/min, representing approximately 2.6% reduction of flow rate available to move the actuator. This is done without a need to model the actuator or leakage. Other methods of leakage fault diagnosis require the model of the actuator or leakage fault. Furthermore, no other method reported the internal leakage detection of magnitude as low as the one reported in this paper. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5256314 [article] A wavelet-based approach to internal seal damage diagnosis in hydraulic actuators [texte imprimé] / Goharrizi, Amin Yazdanpanah, Auteur ; Sepehri, Nariman, Auteur . - 2011 . - pp. 1755 - 1763. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 5 (Mai 2010) . - pp. 1755 - 1763 Mots-clés : Fault  detection  Hydraulic  actuators  Internal  leakage  Wavelet  transform  (WT) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : This paper describes the application of wavelet transform (WT) to detect internal leakage in hydraulic actuators, caused by seal damage. The method analyzes the pressure signal at one side of the actuator in response to periodic step inputs to the control valve. It is shown that the detailed version of decomposed pressure signal, using discrete WT, establishes feature patterns that can effectively detect internal leakage and its severity. The proposed scheme requires a baseline (threshold) value, predetermined first by analyzing the pressure signal of a healthy actuator. Once the root mean square (rms) of the level-two detail coefficient values, obtained from the measured pressure signals in subsequent offline tests, fall below this baseline, a fault alarm is triggered. Furthermore, the degree of changes of the rms value from the one obtained under normal operating condition indicates the severity of fault. Experimental tests show promising results for detecting internal leakages as low as 0.124 L/min, representing approximately 2.6% reduction of flow rate available to move the actuator. This is done without a need to model the actuator or leakage. Other methods of leakage fault diagnosis require the model of the actuator or leakage fault. Furthermore, no other method reported the internal leakage detection of magnitude as low as the one reported in this paper. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5256314