Documents disponibles écrits par cet auteur

Dynamic modeling of damping effects in highly damped compliant fingers for applications involving contacts / Chih-Hsing Liu 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) . - 09 p. Titre : Dynamic modeling of damping effects in highly damped compliant fingers for applications involving contacts Type de document : texte imprimé Auteurs : Chih-Hsing Liu, Auteur ; Kok-Meng, Lee, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : Dynamic systems Langues : Anglais (eng) Mots-clés : Damping  Dexterous  manipulators  Finite  element  analysis  Manipulator  dynamics  Mechanical  contact Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : In many industries, it is often required to transfer objects using compliant fingers capable of accommodating a limited range of object shapes/sizes without causing damage to the products being handled. This paper presents a coupled computational and experimental method in time domain to characterize the damping coefficient of a continuum structure, particularly, its applications for analyzing the damping effect of a highly damped compliant finger on contact-induced forces and stresses. With the aid of Rayleigh damping and explicit dynamic finite element analysis (FEA), this method relaxes several limitations of commonly used damping identification methods (such as log-decrement and half-power methods) that are valid for systems with an oscillatory response and generally estimate the damping ratio for a lumped parameter model. This damping identification method implemented using off-the-shelf commercial FEA packages has been validated by comparing results against published data; both oscillatory and nonoscillatory responses are considered. Along with a detailed discussion on practical issues commonly encountered in explicit dynamic FEA for damping identification, the effects of damping coefficients on contact between a rotating compliant finger and an elliptical object has been numerically investigated and experimentally validated. The findings offer a better understanding for improving grasper designs for applications where joint-less compliant fingers are advantageous. DEWEY : 553 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000001 [...] [article] Dynamic modeling of damping effects in highly damped compliant fingers for applications involving contacts [texte imprimé] / Chih-Hsing Liu, Auteur ; Kok-Meng, Lee, Auteur . - 2012 . - 09 p. Dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 1 (Janvier 2012) . - 09 p. Mots-clés : Damping  Dexterous  manipulators  Finite  element  analysis  Manipulator  dynamics  Mechanical  contact Index. décimale : 553 Géologie économique. Minérographie. Minéraux. Formation et gisements de minerais Résumé : In many industries, it is often required to transfer objects using compliant fingers capable of accommodating a limited range of object shapes/sizes without causing damage to the products being handled. This paper presents a coupled computational and experimental method in time domain to characterize the damping coefficient of a continuum structure, particularly, its applications for analyzing the damping effect of a highly damped compliant finger on contact-induced forces and stresses. With the aid of Rayleigh damping and explicit dynamic finite element analysis (FEA), this method relaxes several limitations of commonly used damping identification methods (such as log-decrement and half-power methods) that are valid for systems with an oscillatory response and generally estimate the damping ratio for a lumped parameter model. This damping identification method implemented using off-the-shelf commercial FEA packages has been validated by comparing results against published data; both oscillatory and nonoscillatory responses are considered. Along with a detailed discussion on practical issues commonly encountered in explicit dynamic FEA for damping identification, the effects of damping coefficients on contact between a rotating compliant finger and an elliptical object has been numerically investigated and experimentally validated. The findings offer a better understanding for improving grasper designs for applications where joint-less compliant fingers are advantageous. DEWEY : 553 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000001 [...]

Open-loop controller design and dynamic characteristics of a spherical wheel motor / Hungsun, Son in IEEE transactions on industrial electronics, Vol. 57 N° 10 (Octobre 2010) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 57 N° 10 (Octobre 2010) . - pp. 3475 - 3482 Titre : Open-loop controller design and dynamic characteristics of a spherical wheel motor Type de document : texte imprimé Auteurs : Hungsun, Son, Auteur ; Kok-Meng, Lee, Auteur Année de publication : 2011 Article en page(s) : pp. 3475 - 3482 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Electromagnetic  (EMs)  Magnetic  dipole  Magnetic  field  Multi-degree-of-freedom  (DOF)  actuator  Open-loop  (OL)  control  Stepping  motor Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : This paper presents a control system design for a particular form of variable-reluctance spherical motors, referred to here as a spherical wheel motor (SWM). The method decoupling the spin from the inclination offers a means to control, in open loop (OL), the inclination of a continuously rotating shaft. Specifically, the OL controller presented in this paper combines a multispeed switching control law for controlling the spin motion and a dynamic model-based control law for regulating the rotor inclination of an SWM. The concept feasibility of the OL-controlled SWM (consisting of permanent magnets in a rotor and electromagnets in a stator) has been experimentally demonstrated. The experimental study not only demonstrates the design procedure but also provides intuitive insights into the effects of key operation parameters on the SWM dynamics. The results presented here will serve as a basis for developing feedback controllers for increasing accuracy and robustness for disturbance rejection. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5406163 [article] Open-loop controller design and dynamic characteristics of a spherical wheel motor [texte imprimé] / Hungsun, Son, Auteur ; Kok-Meng, Lee, Auteur . - 2011 . - pp. 3475 - 3482. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 10 (Octobre 2010) . - pp. 3475 - 3482 Mots-clés : Electromagnetic  (EMs)  Magnetic  dipole  Magnetic  field  Multi-degree-of-freedom  (DOF)  actuator  Open-loop  (OL)  control  Stepping  motor Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : This paper presents a control system design for a particular form of variable-reluctance spherical motors, referred to here as a spherical wheel motor (SWM). The method decoupling the spin from the inclination offers a means to control, in open loop (OL), the inclination of a continuously rotating shaft. Specifically, the OL controller presented in this paper combines a multispeed switching control law for controlling the spin motion and a dynamic model-based control law for regulating the rotor inclination of an SWM. The concept feasibility of the OL-controlled SWM (consisting of permanent magnets in a rotor and electromagnets in a stator) has been experimentally demonstrated. The experimental study not only demonstrates the design procedure but also provides intuitive insights into the effects of key operation parameters on the SWM dynamics. The results presented here will serve as a basis for developing feedback controllers for increasing accuracy and robustness for disturbance rejection. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5406163