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Adaptive piezoelectric vibration control with synchronized switching / J. C. Collinger in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 131 N° 4 (Juillet 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 4 (Juillet 2009) . - 08 p. Titre : Adaptive piezoelectric vibration control with synchronized switching Type de document : texte imprimé Auteurs : J. C. Collinger, Auteur ; J. A. Wickert, Auteur ; L. R. Corr, Auteur Année de publication : 2009 Article en page(s) : 08 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : vibration  controller;  system’s  mass Résumé : An autonomous vibration controller that adapts to variations in a system’s mass, stiffness, and excitation, and that maximizes dissipation through synchronized switching is described. In the model and laboratory measurements, a cantilever beam is driven through base excitation and two piezoelectric elements are attached to the beam for vibration control purposes. The distributed-parameter model for the beam-element system is discretized by using Galerkin’s method, and time histories of the system’s response describe the controller’s attenuation characteristics. The system is piecewise linear, and a state-to-state modal analysis method is developed to simulate the coupled dynamics of the beam and piezoelectric circuit by mapping the generalized coordinates between the sets of modes for the open-switch and closed-switch configurations. In synchronized switching control, the elements are periodically switched to an external resonant shunt, and the instants of optimal switching are identified through a filtered velocity signal. The controller adaptively aligns the center frequency of a bandpass filter to the beam’s fundamental frequency through a fuzzy logic algorithm in order to maximize attenuation even with minimal a priori knowledge of the excitation or the system’s mass and stiffness parameters. In implementation, the controller is compact owing to its low inductance and computational requirement. The adaptive controller attenuates vibration over a range of excitation frequencies and is robust to variations in system parameters, thus outperforming traditional synchronized switching. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...] [article] Adaptive piezoelectric vibration control with synchronized switching [texte imprimé] / J. C. Collinger, Auteur ; J. A. Wickert, Auteur ; L. R. Corr, Auteur . - 2009 . - 08 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 4 (Juillet 2009) . - 08 p. Mots-clés : vibration  controller;  system’s  mass Résumé : An autonomous vibration controller that adapts to variations in a system’s mass, stiffness, and excitation, and that maximizes dissipation through synchronized switching is described. In the model and laboratory measurements, a cantilever beam is driven through base excitation and two piezoelectric elements are attached to the beam for vibration control purposes. The distributed-parameter model for the beam-element system is discretized by using Galerkin’s method, and time histories of the system’s response describe the controller’s attenuation characteristics. The system is piecewise linear, and a state-to-state modal analysis method is developed to simulate the coupled dynamics of the beam and piezoelectric circuit by mapping the generalized coordinates between the sets of modes for the open-switch and closed-switch configurations. In synchronized switching control, the elements are periodically switched to an external resonant shunt, and the instants of optimal switching are identified through a filtered velocity signal. The controller adaptively aligns the center frequency of a bandpass filter to the beam’s fundamental frequency through a fuzzy logic algorithm in order to maximize attenuation even with minimal a priori knowledge of the excitation or the system’s mass and stiffness parameters. In implementation, the controller is compact owing to its low inductance and computational requirement. The adaptive controller attenuates vibration over a range of excitation frequencies and is robust to variations in system parameters, thus outperforming traditional synchronized switching. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...]

Lateral vibration and read/write head servo dynamics in magnetic tape transport / M. R. Brake in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 132 N° 1 (Janvier/Fevrier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 1 (Janvier/Fevrier 2010) . - 11 p. Titre : Lateral vibration and read/write head servo dynamics in magnetic tape transport Type de document : texte imprimé Auteurs : M. R. Brake, Auteur ; J. A. Wickert, Auteur Année de publication : 2010 Article en page(s) : 11 p. Note générale : Systèmes dynamiques Langues : Anglais (eng) Mots-clés : Friction  Magnetic  heads  Magnetic  tapes  Vibrations  Viscoelasticity Index. décimale : 629.8 Résumé : Magnetic tape is a flexible mechanical structure having dimensions that are orders of magnitude different in its thickness, width, and length directions. In order to position the tape relative to the read/write head, guides constrain the tape's lateral motion, but even the modest forces that develop during guiding can cause wear and damage to the tape's edges. This paper presents a tensioned axially-moving viscoelastic Euler–Bernoulli beam model used to simulate the tape's lateral dynamics, the guiding forces, and the position error between the data tracks and the read/write head. Lateral vibration can be excited by disturbances in the form of pack runout, flange impacts, precurvature of the tape in its natural unstressed state, and spiral stacking as tape winds onto the take-up pack. The guide model incorporates nonlinear characteristics including preload and deadbands in displacement and restoring force. A tracking servo model represents the ability of the read/write head's actuator to track disturbances in the tape's motion, and the actuator's motion couples through friction with the tape's vibration. Low frequency excitation arising from pack runout can excite high frequency position error because of the nonlinear characteristics of the guides and impacts against the pack's flanges. The contact force developed between the tape and the packs' flanges can be minimized without significantly increasing the position error by judicious selection of the flanges' taper angle. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...] [article] Lateral vibration and read/write head servo dynamics in magnetic tape transport [texte imprimé] / M. R. Brake, Auteur ; J. A. Wickert, Auteur . - 2010 . - 11 p. Systèmes dynamiques Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 1 (Janvier/Fevrier 2010) . - 11 p. Mots-clés : Friction  Magnetic  heads  Magnetic  tapes  Vibrations  Viscoelasticity Index. décimale : 629.8 Résumé : Magnetic tape is a flexible mechanical structure having dimensions that are orders of magnitude different in its thickness, width, and length directions. In order to position the tape relative to the read/write head, guides constrain the tape's lateral motion, but even the modest forces that develop during guiding can cause wear and damage to the tape's edges. This paper presents a tensioned axially-moving viscoelastic Euler–Bernoulli beam model used to simulate the tape's lateral dynamics, the guiding forces, and the position error between the data tracks and the read/write head. Lateral vibration can be excited by disturbances in the form of pack runout, flange impacts, precurvature of the tape in its natural unstressed state, and spiral stacking as tape winds onto the take-up pack. The guide model incorporates nonlinear characteristics including preload and deadbands in displacement and restoring force. A tracking servo model represents the ability of the read/write head's actuator to track disturbances in the tape's motion, and the actuator's motion couples through friction with the tape's vibration. Low frequency excitation arising from pack runout can excite high frequency position error because of the nonlinear characteristics of the guides and impacts against the pack's flanges. The contact force developed between the tape and the packs' flanges can be minimized without significantly increasing the position error by judicious selection of the flanges' taper angle. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...]