Documents disponibles écrits par cet auteur

Design and analysis of discrete-time repetitive control for scanning probe microscopes / Ugur Aridogan in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 6 (Novembre 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 6 (Novembre 2009) . - 12 p. Titre : Design and analysis of discrete-time repetitive control for scanning probe microscopes Type de document : texte imprimé Auteurs : Ugur Aridogan, Auteur ; Yingfeng Shan, Auteur ; Kam K. Leang, Auteur Année de publication : 2010 Article en page(s) : 12 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : dynamics  (mechanics);  stability;  atomic  force  microscopy;  control  equipment;  motion;  simulation;  scanning  probe  microscopy;  design;  errors;  feedback;  robustness;  steady  state;  imaging Résumé : This paper studies repetitive control (RC) with linear phase lead compensation to precisely track periodic trajectories in piezo-based scanning probe microscopes (SPMs). Quite often, the lateral scanning motion in SPMs during imaging or nanofabrication is periodic. Dynamic and hysteresis effects in the piezoactuator cause significant tracking error. To minimize the tracking error, commercial SPMs commonly use proportional-integral-derivative (PID) feedback controllers; however, the residual error of PID control can be excessively large, especially at high scan rates. In addition, the error repeats from one operating cycle to the next. To account for the periodic tracking error, a discrete-time RC is designed, analyzed, and implemented on an atomic force microscope (AFM). The advantages of RC include straightforward digital implementation and it can be plugged into an existing feedback control loop, such as PID, to enhance performance. The proposed RC incorporates two phase lead compensators to ensure robustness and minimize the steady-state tracking error. Simulation and experimental results from an AFM system compare the performance among (1) PID, (2) standard RC, and (3) the modified RC with phase lead compensation. The results show that the latter reduces the steady-state tracking error to less than 2% at 25 Hz scan rate, an over 80% improvement compared with PID control. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26505&di [...] [article] Design and analysis of discrete-time repetitive control for scanning probe microscopes [texte imprimé] / Ugur Aridogan, Auteur ; Yingfeng Shan, Auteur ; Kam K. Leang, Auteur . - 2010 . - 12 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 6 (Novembre 2009) . - 12 p. Mots-clés : dynamics  (mechanics);  stability;  atomic  force  microscopy;  control  equipment;  motion;  simulation;  scanning  probe  microscopy;  design;  errors;  feedback;  robustness;  steady  state;  imaging Résumé : This paper studies repetitive control (RC) with linear phase lead compensation to precisely track periodic trajectories in piezo-based scanning probe microscopes (SPMs). Quite often, the lateral scanning motion in SPMs during imaging or nanofabrication is periodic. Dynamic and hysteresis effects in the piezoactuator cause significant tracking error. To minimize the tracking error, commercial SPMs commonly use proportional-integral-derivative (PID) feedback controllers; however, the residual error of PID control can be excessively large, especially at high scan rates. In addition, the error repeats from one operating cycle to the next. To account for the periodic tracking error, a discrete-time RC is designed, analyzed, and implemented on an atomic force microscope (AFM). The advantages of RC include straightforward digital implementation and it can be plugged into an existing feedback control loop, such as PID, to enhance performance. The proposed RC incorporates two phase lead compensators to ensure robustness and minimize the steady-state tracking error. Simulation and experimental results from an AFM system compare the performance among (1) PID, (2) standard RC, and (3) the modified RC with phase lead compensation. The results show that the latter reduces the steady-state tracking error to less than 2% at 25 Hz scan rate, an over 80% improvement compared with PID control. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26505&di [...]

Iterative and feedback control for hysteresis compensation in SMA / Kam K. Leang in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N°1 (Janvier/Février 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N°1 (Janvier/Février 2009) . - 06 p. Titre : Iterative and feedback control for hysteresis compensation in SMA Type de document : texte imprimé Auteurs : Kam K. Leang, Auteur ; Seth Ashley, Auteur ; Guy Tchoupo, Auteur Année de publication : 2009 Article en page(s) : 06 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : phase  transitions;  control  equipment;  actuators;  design;  errors;  feedback Résumé : This paper investigates the design of an iteration-based controller combined with feedback control to address the positioning error caused by hysteresis in a shape memory alloy (SMA) actuator. Without compensation, the positioning error due to hysteresis can be excessively large (greater than 20%), therefore limiting the performance of SMAs in positioning applications. An iterative controller based on the Preisach hysteresis model is used to compensate for the hysteresis. However, one of the major challenges with SMA at or near the phase-transition zones, from martensite to austenite and vice versa, is the output response is shown to be sensitive to small changes in the input. In practice, an iterative controller provides limited performance due to lack of robustness. It is demonstrated that combining a simple feedback controller with an iterative controller provides the needed robustness to enable high-precision tracking. Experimental results are presented that show maximum tracking error of 0.15% of the total displacement range—this value is approximately the noise level of the sensor measurement. DEWEY : 629.8 ISSN : 0022-0434 En ligne : dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&issueid=2 [...] [article] Iterative and feedback control for hysteresis compensation in SMA [texte imprimé] / Kam K. Leang, Auteur ; Seth Ashley, Auteur ; Guy Tchoupo, Auteur . - 2009 . - 06 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N°1 (Janvier/Février 2009) . - 06 p. Mots-clés : phase  transitions;  control  equipment;  actuators;  design;  errors;  feedback Résumé : This paper investigates the design of an iteration-based controller combined with feedback control to address the positioning error caused by hysteresis in a shape memory alloy (SMA) actuator. Without compensation, the positioning error due to hysteresis can be excessively large (greater than 20%), therefore limiting the performance of SMAs in positioning applications. An iterative controller based on the Preisach hysteresis model is used to compensate for the hysteresis. However, one of the major challenges with SMA at or near the phase-transition zones, from martensite to austenite and vice versa, is the output response is shown to be sensitive to small changes in the input. In practice, an iterative controller provides limited performance due to lack of robustness. It is demonstrated that combining a simple feedback controller with an iterative controller provides the needed robustness to enable high-precision tracking. Experimental results are presented that show maximum tracking error of 0.15% of the total displacement range—this value is approximately the noise level of the sensor measurement. DEWEY : 629.8 ISSN : 0022-0434 En ligne : dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&issueid=2 [...]

A review of feedforward control approaches in nanopositioning for high-speed SPM / Garrett M. Clayton in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 6 (Novembre 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 6 (Novembre 2009) . - 19 p. Titre : A review of feedforward control approaches in nanopositioning for high-speed SPM Type de document : texte imprimé Auteurs : Garrett M. Clayton, Auteur ; Szuchi Tien, Auteur ; Kam K. Leang, Auteur Année de publication : 2010 Article en page(s) : 19 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : scanning  probe  microscopy;  errors;  feedforward  control;  probes;  imaging Résumé : Control can enable high-bandwidth nanopositioning needed to increase the operating speed of scanning probe microscopes (SPMs). High-speed SPMs can substantially impact the throughput of a wide range of emerging nanosciences and nanotechnologies. In particular, inversion-based control can find the feedforward input needed to account for the positioning dynamics and, thus, achieve the required precision and bandwidth. This article reviews inversion-based feedforward approaches used for high-speed SPMs such as optimal inversion that accounts for model uncertainty and inversion-based iterative control for repetitive applications. The article establishes connections to other existing methods such as zero-phase-error-tracking feedforward and robust feedforward. Additionally, the article reviews the use of feedforward in emerging applications such as SPM-based nanoscale combinatorial-science studies, image-based control for subnanometer-scale studies, and imaging of large soft biosamples with SPMs. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26505&di [...] [article] A review of feedforward control approaches in nanopositioning for high-speed SPM [texte imprimé] / Garrett M. Clayton, Auteur ; Szuchi Tien, Auteur ; Kam K. Leang, Auteur . - 2010 . - 19 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 6 (Novembre 2009) . - 19 p. Mots-clés : scanning  probe  microscopy;  errors;  feedforward  control;  probes;  imaging Résumé : Control can enable high-bandwidth nanopositioning needed to increase the operating speed of scanning probe microscopes (SPMs). High-speed SPMs can substantially impact the throughput of a wide range of emerging nanosciences and nanotechnologies. In particular, inversion-based control can find the feedforward input needed to account for the positioning dynamics and, thus, achieve the required precision and bandwidth. This article reviews inversion-based feedforward approaches used for high-speed SPMs such as optimal inversion that accounts for model uncertainty and inversion-based iterative control for repetitive applications. The article establishes connections to other existing methods such as zero-phase-error-tracking feedforward and robust feedforward. Additionally, the article reviews the use of feedforward in emerging applications such as SPM-based nanoscale combinatorial-science studies, image-based control for subnanometer-scale studies, and imaging of large soft biosamples with SPMs. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26505&di [...]