Dépouillements

Rapid Swing-Free Transport of nonlinear payloads using dynamic programming / Daniel Zameroski in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Titre : Rapid Swing-Free Transport of nonlinear payloads using dynamic programming Type de document : texte imprimé Auteurs : Daniel Zameroski, Auteur ; Gregory Starr, Auteur ; John Wood, Auteur Année de publication : 2008 Article en page(s) : 11 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : oscillations;  motion;  simulation;  trajectories  (physics);  algorithms;  nonlinear  systems;  optimization;  dynamic  programming;  manipulators;  Matlab;  equations;  equations  of  motion Résumé : Residual vibration suppression in freely suspended payload transports has been the focus of extensive work in the past. Many methods have been used to address this problem, including both open-loop motion planning and closed-loop control techniques. However, to be effective, most of these methods require linearization of the system and, in turn, have been restricted in their maneuver speeds. The inherent nonlinearity of suspended payload systems suggests the need for a more rigorous method, where the complete dynamic description can be retained throughout the optimization. Dynamic programming (DP) is such a method. This paper will outline the development of the DP algorithm for a discrete time system as well as its application to the rapid transport of a doubly suspended payload, a nonlinear system. The system consists of a long slender payload, suspended by a cable at each end. The two cables are each held by an independent robot manipulator. We will show that DP is effective at reducing residual oscillations for nonlinear systems, as demonstrated by both simulations and experimental validation. Residual oscillations were suppressed to less than 5% of their original magnitudes. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Rapid Swing-Free Transport of nonlinear payloads using dynamic programming [texte imprimé] / Daniel Zameroski, Auteur ; Gregory Starr, Auteur ; John Wood, Auteur . - 2008 . - 11 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Mots-clés : oscillations;  motion;  simulation;  trajectories  (physics);  algorithms;  nonlinear  systems;  optimization;  dynamic  programming;  manipulators;  Matlab;  equations;  equations  of  motion Résumé : Residual vibration suppression in freely suspended payload transports has been the focus of extensive work in the past. Many methods have been used to address this problem, including both open-loop motion planning and closed-loop control techniques. However, to be effective, most of these methods require linearization of the system and, in turn, have been restricted in their maneuver speeds. The inherent nonlinearity of suspended payload systems suggests the need for a more rigorous method, where the complete dynamic description can be retained throughout the optimization. Dynamic programming (DP) is such a method. This paper will outline the development of the DP algorithm for a discrete time system as well as its application to the rapid transport of a doubly suspended payload, a nonlinear system. The system consists of a long slender payload, suspended by a cable at each end. The two cables are each held by an independent robot manipulator. We will show that DP is effective at reducing residual oscillations for nonlinear systems, as demonstrated by both simulations and experimental validation. Residual oscillations were suppressed to less than 5% of their original magnitudes. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Variable structure decentralized control and estimation for highway traffic systems / Rafael Becerril-Arreola in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Titre : Variable structure decentralized control and estimation for highway traffic systems Type de document : texte imprimé Auteurs : Rafael Becerril-Arreola, Auteur ; Rashid R. Kohan, Auteur ; Amir G. Aghdam, Auteur Année de publication : 2008 Article en page(s) : 11 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : flow  (dynamics);  control  equipment;  design;  highways;  traffic;  errors Résumé : This work is concerned with the decentralized control of traffic flow in highways using on-ramp metering and variable structure techniques. Both the estimation and the robust control problem are studied. Sliding mode observers are first proposed to estimate the state of neighboring highway segments in a two-highway-link model. Two independent variable structure controllers use the resulting estimates to locally stabilize the traffic flow around a desired set point, even if accurate estimation is not always possible. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Variable structure decentralized control and estimation for highway traffic systems [texte imprimé] / Rafael Becerril-Arreola, Auteur ; Rashid R. Kohan, Auteur ; Amir G. Aghdam, Auteur . - 2008 . - 11 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Mots-clés : flow  (dynamics);  control  equipment;  design;  highways;  traffic;  errors Résumé : This work is concerned with the decentralized control of traffic flow in highways using on-ramp metering and variable structure techniques. Both the estimation and the robust control problem are studied. Sliding mode observers are first proposed to estimate the state of neighboring highway segments in a two-highway-link model. Two independent variable structure controllers use the resulting estimates to locally stabilize the traffic flow around a desired set point, even if accurate estimation is not always possible. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Characterization of the dynamical response of a micromachined G-sensor to mechanical shock loading / Daniel Jordy in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Titre : Characterization of the dynamical response of a micromachined G-sensor to mechanical shock loading Type de document : texte imprimé Auteurs : Daniel Jordy, Auteur ; Younis, Mohammad I., Auteur Année de publication : 2008 Article en page(s) : 9 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : sensors;  shock  (mechanics);  damping;  microelectromechanical  systems;  stiction;  motion Résumé : Squeeze film damping has a significant effect on the dynamic response of microelectromechanical system (MEMS) devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering damping. By decreasing the size of the holes, damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, the performance of a G-sensor (threshold accelerometer) employed in an arming and fusing chip is investigated. The effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate are studied. A multiphysics finite-element model built using the software ANSYS is utilized for the fluidic and transient structural analysis. A squeeze film damping model, for both the air underneath the structure and the flow of the air through the perforations, is developed. Results are shown for various models of squeeze film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. It is found that the threshold of shock that causes the G-sensor to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Characterization of the dynamical response of a micromachined G-sensor to mechanical shock loading [texte imprimé] / Daniel Jordy, Auteur ; Younis, Mohammad I., Auteur . - 2008 . - 9 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Mots-clés : sensors;  shock  (mechanics);  damping;  microelectromechanical  systems;  stiction;  motion Résumé : Squeeze film damping has a significant effect on the dynamic response of microelectromechanical system (MEMS) devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering damping. By decreasing the size of the holes, damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, the performance of a G-sensor (threshold accelerometer) employed in an arming and fusing chip is investigated. The effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate are studied. A multiphysics finite-element model built using the software ANSYS is utilized for the fluidic and transient structural analysis. A squeeze film damping model, for both the air underneath the structure and the flow of the air through the perforations, is developed. Results are shown for various models of squeeze film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. It is found that the threshold of shock that causes the G-sensor to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

An energetic control methodology for exploiting the passive dynamics of pneumatically actuated hopping / Yong Zhu in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Titre : An energetic control methodology for exploiting the passive dynamics of pneumatically actuated hopping Type de document : texte imprimé Auteurs : Yong Zhu, Auteur ; Barth, Eric J., Auteur Année de publication : 2008 Article en page(s) : 11 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : dynamics  (mechanics);  pressure;  motion;  robots;  actuators;  valves;  pistons;  flight;  stiffness;  potential  energy;  solenoids;  flow  (dynamics);  kinetic  energy;  oscillations;  simulation;  force;  pneumatic  actuators;  energy  storage;  equilibrium  (physics);  cylinders;  pneumatic  cylinders;  proportional  valves Résumé : This paper presents an energetically derived control methodology to specify and regulate the oscillatory motion of a pneumatic hopping robot. An ideal lossless pneumatic actuation system with an inertia is shown to represent an oscillator with a stiffness, and hence frequency, related to the equilibrium pressures in the actuator. Following from an analysis of the conservative energy storage elements in the system, a control methodology is derived to sustain a specified frequency of oscillation in the presence of energy dissipation. The basic control strategy is to control the pressure in the upper chamber of the pneumatic cylinder to specify the contact time of the piston, while controlling the total conservative energy stored in the system to specify the flight time and corresponding flight height of the cylinder. The control strategy takes advantage of the natural passive dynamics of the upper chamber to provide much of the required actuation forces and natural stiffness, while the remaining forces needed to overcome the energy dissipation present in a nonideal system with losses are provided by a nonlinear control law for the charging and discharging of the lower chamber of the cylinder. Efficient hopping motion, relative to a traditional nonconservative actuator, is achieved by allowing the energy storing capability of a pneumatic actuator to store and return energy to the system at a controlled specifiable frequency. The control methodology is demonstrated through simulation and experimental results to provide accurate and repeatable hopping motion for pneumatically actuated robots in the presence of dissipative forces. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] An energetic control methodology for exploiting the passive dynamics of pneumatically actuated hopping [texte imprimé] / Yong Zhu, Auteur ; Barth, Eric J., Auteur . - 2008 . - 11 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 11 p. Mots-clés : dynamics  (mechanics);  pressure;  motion;  robots;  actuators;  valves;  pistons;  flight;  stiffness;  potential  energy;  solenoids;  flow  (dynamics);  kinetic  energy;  oscillations;  simulation;  force;  pneumatic  actuators;  energy  storage;  equilibrium  (physics);  cylinders;  pneumatic  cylinders;  proportional  valves Résumé : This paper presents an energetically derived control methodology to specify and regulate the oscillatory motion of a pneumatic hopping robot. An ideal lossless pneumatic actuation system with an inertia is shown to represent an oscillator with a stiffness, and hence frequency, related to the equilibrium pressures in the actuator. Following from an analysis of the conservative energy storage elements in the system, a control methodology is derived to sustain a specified frequency of oscillation in the presence of energy dissipation. The basic control strategy is to control the pressure in the upper chamber of the pneumatic cylinder to specify the contact time of the piston, while controlling the total conservative energy stored in the system to specify the flight time and corresponding flight height of the cylinder. The control strategy takes advantage of the natural passive dynamics of the upper chamber to provide much of the required actuation forces and natural stiffness, while the remaining forces needed to overcome the energy dissipation present in a nonideal system with losses are provided by a nonlinear control law for the charging and discharging of the lower chamber of the cylinder. Efficient hopping motion, relative to a traditional nonconservative actuator, is achieved by allowing the energy storing capability of a pneumatic actuator to store and return energy to the system at a controlled specifiable frequency. The control methodology is demonstrated through simulation and experimental results to provide accurate and repeatable hopping motion for pneumatically actuated robots in the presence of dissipative forces. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

MIMO active vibration control of magnetically suspended flywheels for satellite IPAC service / Park, Junyoung in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 22 p. Titre : MIMO active vibration control of magnetically suspended flywheels for satellite IPAC service Type de document : texte imprimé Auteurs : Park, Junyoung, Auteur ; Raymond Beach, Auteur ; Palazzolo, Alan, Auteur Année de publication : 2008 Article en page(s) : 22 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : force;  motion;  flywheels;  satellites Résumé : Theory and simulation results have demonstrated that four, variable speed flywheels could potentially provide the energy storage and attitude control functions of existing batteries and control moment gyros on a satellite. Past modeling and control algorithms were based on the assumption of rigidity in the flywheel’s bearings and the satellite structure. This paper provides simulation results and theory, which eliminates this assumption utilizing control algorithms for active vibration control (AVC), flywheel shaft levitation, and integrated power transfer and attitude control (IPAC), that are effective even with low stiffness active magnetic bearings (AMBs) and flexible satellite appendages. The flywheel AVC and levitation tasks are provided by a multiple input–multiple output control law that enhances stability by reducing the dependence of the forward and backward gyroscopic poles with changes in flywheel speed. The control law is shown to be effective even for (1) large polar to transverse inertia ratios, which increases the stored energy density while causing the poles to become more speed dependent, and for (2) low bandwidth controllers shaped to suppress high frequency noise. Passive vibration dampers are designed to reduce the vibrations of flexible appendages of the satellite. Notch, low-pass, and bandpass filters are implemented in the AMB system to reduce and cancel high frequency, dynamic bearing forces and motor torques due to flywheel mass imbalance. Successful IPAC simulation results are presented with a 12% initial attitude error, large polar to transverse inertia ratio (IP∕IT), structural flexibility, and unbalance mass disturbance. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] MIMO active vibration control of magnetically suspended flywheels for satellite IPAC service [texte imprimé] / Park, Junyoung, Auteur ; Raymond Beach, Auteur ; Palazzolo, Alan, Auteur . - 2008 . - 22 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 22 p. Mots-clés : force;  motion;  flywheels;  satellites Résumé : Theory and simulation results have demonstrated that four, variable speed flywheels could potentially provide the energy storage and attitude control functions of existing batteries and control moment gyros on a satellite. Past modeling and control algorithms were based on the assumption of rigidity in the flywheel’s bearings and the satellite structure. This paper provides simulation results and theory, which eliminates this assumption utilizing control algorithms for active vibration control (AVC), flywheel shaft levitation, and integrated power transfer and attitude control (IPAC), that are effective even with low stiffness active magnetic bearings (AMBs) and flexible satellite appendages. The flywheel AVC and levitation tasks are provided by a multiple input–multiple output control law that enhances stability by reducing the dependence of the forward and backward gyroscopic poles with changes in flywheel speed. The control law is shown to be effective even for (1) large polar to transverse inertia ratios, which increases the stored energy density while causing the poles to become more speed dependent, and for (2) low bandwidth controllers shaped to suppress high frequency noise. Passive vibration dampers are designed to reduce the vibrations of flexible appendages of the satellite. Notch, low-pass, and bandpass filters are implemented in the AMB system to reduce and cancel high frequency, dynamic bearing forces and motor torques due to flywheel mass imbalance. Successful IPAC simulation results are presented with a 12% initial attitude error, large polar to transverse inertia ratio (IP∕IT), structural flexibility, and unbalance mass disturbance. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Multiharmonic adaptive vibration control of misaligned driveline via active magnetic bearings / Hans A. DeSmidt in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 13 p. Titre : Multiharmonic adaptive vibration control of misaligned driveline via active magnetic bearings Type de document : texte imprimé Auteurs : Hans A. DeSmidt, Auteur ; Wang, K. W., Auteur ; Edward C. Smith, Auteur Année de publication : 2008 Article en page(s) : 13 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : torque;  stability;  stress;  vibration  control;  damping;  design;  vibration;  feedback;  magnetic  bearings;  robustness;  whirls;  rotors;  steady  state;  universal  joints;  stiffness Résumé : Active magnetic bearings (AMBs) have been proposed by many researchers and engineers as an alternative to replace traditional contact bearings in rotor and driveshaft systems. Such active, noncontact bearings do not have frictional wear and can be used to suppress vibration in sub- and supercritical rotor-dynamic applications. One important issue that has not yet been addressed by previous AMB-driveline control studies is the effect of driveline misalignment. Previous research has shown that misalignment causes periodic parametric and forcing actions, which greatly impact both driveline stability and vibration levels. Therefore, in order to ensure closed-loop stability and acceptable performance of any AMB controlled driveline subjected to misalignment, these effects must be accounted for in the control system design. In this paper, a hybrid proportional derivative (PD) feedback/multiharmonic adaptive vibration control (MHAVC) feedforward law is developed for an AMB/U-joint-driveline system, which is subjected to parallel-offset misalignments, imbalance, and load-torque operating conditions. Conceptually, the PD feedback ensures closed-loop stability while the MHAVC feedforward suppresses steady-state vibration. It is found that there is a range of P and D feedback gains that ensures both MHAVC convergence and closed-loop stability robustness with respect to shaft internal damping induced whirl and misalignment effects. Finally, it is analytically and experimentally demonstrated that the hybrid PD-MHAVC law effectively adapts to and suppresses multiharmonic vibration induced by imbalance, misalignment, and load-torque effects at multiple operating speeds without explicit knowledge of the disturbance conditions. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Multiharmonic adaptive vibration control of misaligned driveline via active magnetic bearings [texte imprimé] / Hans A. DeSmidt, Auteur ; Wang, K. W., Auteur ; Edward C. Smith, Auteur . - 2008 . - 13 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 13 p. Mots-clés : torque;  stability;  stress;  vibration  control;  damping;  design;  vibration;  feedback;  magnetic  bearings;  robustness;  whirls;  rotors;  steady  state;  universal  joints;  stiffness Résumé : Active magnetic bearings (AMBs) have been proposed by many researchers and engineers as an alternative to replace traditional contact bearings in rotor and driveshaft systems. Such active, noncontact bearings do not have frictional wear and can be used to suppress vibration in sub- and supercritical rotor-dynamic applications. One important issue that has not yet been addressed by previous AMB-driveline control studies is the effect of driveline misalignment. Previous research has shown that misalignment causes periodic parametric and forcing actions, which greatly impact both driveline stability and vibration levels. Therefore, in order to ensure closed-loop stability and acceptable performance of any AMB controlled driveline subjected to misalignment, these effects must be accounted for in the control system design. In this paper, a hybrid proportional derivative (PD) feedback/multiharmonic adaptive vibration control (MHAVC) feedforward law is developed for an AMB/U-joint-driveline system, which is subjected to parallel-offset misalignments, imbalance, and load-torque operating conditions. Conceptually, the PD feedback ensures closed-loop stability while the MHAVC feedforward suppresses steady-state vibration. It is found that there is a range of P and D feedback gains that ensures both MHAVC convergence and closed-loop stability robustness with respect to shaft internal damping induced whirl and misalignment effects. Finally, it is analytically and experimentally demonstrated that the hybrid PD-MHAVC law effectively adapts to and suppresses multiharmonic vibration induced by imbalance, misalignment, and load-torque effects at multiple operating speeds without explicit knowledge of the disturbance conditions. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Robust control of a parallel- kinematic nanopositioner / Jingyan Dong in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 15 p. Titre : Robust control of a parallel- kinematic nanopositioner Type de document : texte imprimé Auteurs : Jingyan Dong, Auteur ; Srinivasa M. Salapaka, Auteur ; Placid M. Ferreira, Auteur Année de publication : 2008 Article en page(s) : 15 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : control  equipment;  motion;  transfer  functions;  design;  robust  control;  piezoelectric  actuators;  actuators;  resolution  (optics);  end  effectors;  bending  (stress);  signals;  displacement;  errors;  mechanisms Résumé : This paper presents the design, model identification, and control of a parallel-kinematic XYZ nanopositioning stage for general nanomanipulation and nanomanufacturing applications. The stage has a low degree-of-freedom monolithic parallel-kinematic mechanism featuring single-axis flexure hinges. The stage is driven by piezoelectric actuators, and its displacement is detected by capacitance gauges. The control loop is closed at the end effector instead of at each joint, so as to avoid calibration difficulties and guarantee high positioning accuracy. This design has strongly coupled dynamics with each actuator input producing in multiaxis motions. The nanopositioner is modeled as a multiple input and multiple output (MIMO) system, where the control design forms an important constituent in view of the strongly coupled dynamics. The dynamics that model the MIMO plant is identified by frequency domain and time-domain identification methods. The control design based on modern robust control theory that gives a high bandwidth closed loop nanopositioning system, which is robust to physical model uncertainties arising from flexure-based mechanisms, is presented. The bandwidth, resolution, and repeatability are characterized experimentally, which demonstrate the effectiveness of the robust control approach. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Robust control of a parallel- kinematic nanopositioner [texte imprimé] / Jingyan Dong, Auteur ; Srinivasa M. Salapaka, Auteur ; Placid M. Ferreira, Auteur . - 2008 . - 15 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 15 p. Mots-clés : control  equipment;  motion;  transfer  functions;  design;  robust  control;  piezoelectric  actuators;  actuators;  resolution  (optics);  end  effectors;  bending  (stress);  signals;  displacement;  errors;  mechanisms Résumé : This paper presents the design, model identification, and control of a parallel-kinematic XYZ nanopositioning stage for general nanomanipulation and nanomanufacturing applications. The stage has a low degree-of-freedom monolithic parallel-kinematic mechanism featuring single-axis flexure hinges. The stage is driven by piezoelectric actuators, and its displacement is detected by capacitance gauges. The control loop is closed at the end effector instead of at each joint, so as to avoid calibration difficulties and guarantee high positioning accuracy. This design has strongly coupled dynamics with each actuator input producing in multiaxis motions. The nanopositioner is modeled as a multiple input and multiple output (MIMO) system, where the control design forms an important constituent in view of the strongly coupled dynamics. The dynamics that model the MIMO plant is identified by frequency domain and time-domain identification methods. The control design based on modern robust control theory that gives a high bandwidth closed loop nanopositioning system, which is robust to physical model uncertainties arising from flexure-based mechanisms, is presented. The bandwidth, resolution, and repeatability are characterized experimentally, which demonstrate the effectiveness of the robust control approach. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

An optimal control approach to minimizing entropy generation in an adiabatic internal combustion engine / Kwee-Yan Teh in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 10 p. Titre : An optimal control approach to minimizing entropy generation in an adiabatic internal combustion engine Type de document : texte imprimé Auteurs : Kwee-Yan Teh, Auteur ; Edwards, Christopher F., Auteur Année de publication : 2008 Article en page(s) : 10 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : entropy;  equilibrium  (physics);  optimal  control;  combustion;  engines;  mixtures;  piston  engines Résumé : Entropy generation due to combustion destroys as much as a third of the theoretical maximum work that could have been extracted from the fuel supplied to an engine. Yet, there is no fundamental study in the literature that addresses the question of how this quantity can be minimized so as to improve combustion engine efficiency. This paper fills the gap by establishing the minimum entropy generated in an adiabatic, homogeneous combustion piston engine. The minimization problem is cast as a dynamical system optimal control problem, with the piston velocity profile serving as the control input function. The closed-form switching condition for the optimal bang-bang control is determined based on Pontryagin’s maximum principle. The switched control is shown to be a function of the pressure difference between the instantaneous thermodynamic state of the system and its corresponding equilibrium thermodynamic state at the same internal energy and volume. At optimality, the entropy difference between these two thermodynamic states is shown to be a Lyapunov function. In thermodynamic terms, the optimal solution reduces to a strategy of equilibrium entropy minimization. This result is independent of the underlying combustion mechanism. It precludes the possibility of matching the piston motion in some sophisticated fashion to the nonlinear combustion kinetics in order to improve the engine efficiency. For illustration, a series of numerical examples are presented that compare the optimal bang-bang solution with the nonoptimal conventional solution based on slider-crank piston motion. Based on the solution for minimum entropy generation, a bound for the maximum expansion work that the piston engine is capable of producing is also deduced. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] An optimal control approach to minimizing entropy generation in an adiabatic internal combustion engine [texte imprimé] / Kwee-Yan Teh, Auteur ; Edwards, Christopher F., Auteur . - 2008 . - 10 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 10 p. Mots-clés : entropy;  equilibrium  (physics);  optimal  control;  combustion;  engines;  mixtures;  piston  engines Résumé : Entropy generation due to combustion destroys as much as a third of the theoretical maximum work that could have been extracted from the fuel supplied to an engine. Yet, there is no fundamental study in the literature that addresses the question of how this quantity can be minimized so as to improve combustion engine efficiency. This paper fills the gap by establishing the minimum entropy generated in an adiabatic, homogeneous combustion piston engine. The minimization problem is cast as a dynamical system optimal control problem, with the piston velocity profile serving as the control input function. The closed-form switching condition for the optimal bang-bang control is determined based on Pontryagin’s maximum principle. The switched control is shown to be a function of the pressure difference between the instantaneous thermodynamic state of the system and its corresponding equilibrium thermodynamic state at the same internal energy and volume. At optimality, the entropy difference between these two thermodynamic states is shown to be a Lyapunov function. In thermodynamic terms, the optimal solution reduces to a strategy of equilibrium entropy minimization. This result is independent of the underlying combustion mechanism. It precludes the possibility of matching the piston motion in some sophisticated fashion to the nonlinear combustion kinetics in order to improve the engine efficiency. For illustration, a series of numerical examples are presented that compare the optimal bang-bang solution with the nonoptimal conventional solution based on slider-crank piston motion. Based on the solution for minimum entropy generation, a bound for the maximum expansion work that the piston engine is capable of producing is also deduced. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Discrete-time control of linear time-periodic systems / S. Kalender in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Titre : Discrete-time control of linear time-periodic systems Type de document : texte imprimé Auteurs : S. Kalender, Auteur ; H. Flashner, Auteur Année de publication : 2008 Article en page(s) : 9 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : sampling  (acoustical  engineering);  design;  feedback;  control  equipment Résumé : A discrete-time control design approach for periodically time-varying systems is introduced. The method employs a period-to-period (point-mapping) formulation of the system’s dynamics and a parametrization of the control input to obtain an equivalent time-invariant discrete-time representation of the system. The representation is generalized to include sampling within the period and varying sampling rates in different feedback loops. The proposed formulation allows for the design of feedback control laws using established discrete-time control methodologies. In this paper, dead-beat and optimal control laws with state- or output-feedback control are presented. An example of a multivariable control design for double inverted pendulum with periodic forcing is used to illustrate the proposed approach. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Discrete-time control of linear time-periodic systems [texte imprimé] / S. Kalender, Auteur ; H. Flashner, Auteur . - 2008 . - 9 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Mots-clés : sampling  (acoustical  engineering);  design;  feedback;  control  equipment Résumé : A discrete-time control design approach for periodically time-varying systems is introduced. The method employs a period-to-period (point-mapping) formulation of the system’s dynamics and a parametrization of the control input to obtain an equivalent time-invariant discrete-time representation of the system. The representation is generalized to include sampling within the period and varying sampling rates in different feedback loops. The proposed formulation allows for the design of feedback control laws using established discrete-time control methodologies. In this paper, dead-beat and optimal control laws with state- or output-feedback control are presented. An example of a multivariable control design for double inverted pendulum with periodic forcing is used to illustrate the proposed approach. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

H∞ fuzzy tracking control design for nonlinear active fault tolerant control systems / Wu, Huai-Ning in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Titre : H∞ fuzzy tracking control design for nonlinear active fault tolerant control systems Type de document : texte imprimé Auteurs : Wu, Huai-Ning, Auteur ; Ming-Zhen Bai, Auteur Année de publication : 2008 Article en page(s) : 9 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : control  systems;  design;  tracking  control;  fuzzy  logic;  control  equipment;  design  methodology;  stability;  errors Résumé : This paper studies the problem of H∞ fuzzy tracking control design for nonlinear active fault tolerant control systems based on the Takagi and Sugeno fuzzy model. Two random processes with Markovian transition characteristics are introduced to model the system component fault process and the fault detection and isolation decision process used to reconfigure the control law, respectively. The random behavior of the FDI process is conditioned on the fault process state. The parallel distributed compensation scheme is employed for the control design. As a result, a closed-loop fuzzy system with two Markovian jump parameters is obtained. Based on a stochastic Lyapunov function, a sufficient condition for stochastic stability of the closed-loop fuzzy system with a guaranteed H∞ model reference tracking performance is first derived. A linear matrix inequality approach to the control design is then developed to reduce the effect of the external disturbance and reference input on tracking error as small as possible. Finally, a simulation example is presented to illustrate the effectiveness of the proposed design method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] H∞ fuzzy tracking control design for nonlinear active fault tolerant control systems [texte imprimé] / Wu, Huai-Ning, Auteur ; Ming-Zhen Bai, Auteur . - 2008 . - 9 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Mots-clés : control  systems;  design;  tracking  control;  fuzzy  logic;  control  equipment;  design  methodology;  stability;  errors Résumé : This paper studies the problem of H∞ fuzzy tracking control design for nonlinear active fault tolerant control systems based on the Takagi and Sugeno fuzzy model. Two random processes with Markovian transition characteristics are introduced to model the system component fault process and the fault detection and isolation decision process used to reconfigure the control law, respectively. The random behavior of the FDI process is conditioned on the fault process state. The parallel distributed compensation scheme is employed for the control design. As a result, a closed-loop fuzzy system with two Markovian jump parameters is obtained. Based on a stochastic Lyapunov function, a sufficient condition for stochastic stability of the closed-loop fuzzy system with a guaranteed H∞ model reference tracking performance is first derived. A linear matrix inequality approach to the control design is then developed to reduce the effect of the external disturbance and reference input on tracking error as small as possible. Finally, a simulation example is presented to illustrate the effectiveness of the proposed design method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Full operating range robust hybrid control of a coal-fired boiler/turbine unit / Kai Zheng in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 14 p. Titre : Full operating range robust hybrid control of a coal-fired boiler/turbine unit Type de document : texte imprimé Auteurs : Kai Zheng, Auteur ; Cyrus W. Taft, Auteur ; Joseph Bentsman, Auteur Année de publication : 2008 Article en page(s) : 14 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : control  equipment;  boilers;  design;  turbines;  steady  state;  uncertainty;  hybrid  control;  topology Résumé : Multi-input-multi-output robust controllers recently designed for the megawatt output/throttle pressure control in a coal-fired power plant boiler/turbine unit have demonstrated performance robustness noticeably superior to that of the currently employed nonlinear PID-based controller. These controllers, however, have been designed only for the range of 150–185MW around the 185MW nominal operating point, exhibiting a significant loss of performance in the lower range of 120–150MW. Through system identification, the reason for this performance loss is demonstrated in the current work to be a pronounced dependence of the boiler/turbine unit steady state gains on the operating point. This problem is addressed via a hybrid control law consisting of two robust controllers and a robust switch between them activated by the set point change. The controllers are designed to cover the corresponding half-ranges of the full operating range. This permits attainment of the desired overall performance as well as reduction of modeling uncertainty induced by the operating point change to approximately 25% of that associated with the previous designs. Robust switching is accomplished through a novel hybrid mode of behavior—robustly controlled discrete transition. The latter mode is produced through realizing that the off-line transfer speedup suggested by and (2005, “ The L2(l2) bumpless Transfer Problem for Linear Parts: Its Definition and Solution,” Automatica, 41, pp. 1273–1280) can be taken to the limit and incorporating the result into a robust bumpless transfer technique recently developed by the authors. As demonstrated by simulation results, the proposed strategy provides an adequate solution to the problem of robust boiler/turbine unit performance over the full operating range. This fact combined with numerical algorithm tractability, relative ease of its design, its insensitivity to implementation nonidealities, and accompanying identification methodology for nominal model generation makes it a viable candidate for industrial acceptance. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Full operating range robust hybrid control of a coal-fired boiler/turbine unit [texte imprimé] / Kai Zheng, Auteur ; Cyrus W. Taft, Auteur ; Joseph Bentsman, Auteur . - 2008 . - 14 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 14 p. Mots-clés : control  equipment;  boilers;  design;  turbines;  steady  state;  uncertainty;  hybrid  control;  topology Résumé : Multi-input-multi-output robust controllers recently designed for the megawatt output/throttle pressure control in a coal-fired power plant boiler/turbine unit have demonstrated performance robustness noticeably superior to that of the currently employed nonlinear PID-based controller. These controllers, however, have been designed only for the range of 150–185MW around the 185MW nominal operating point, exhibiting a significant loss of performance in the lower range of 120–150MW. Through system identification, the reason for this performance loss is demonstrated in the current work to be a pronounced dependence of the boiler/turbine unit steady state gains on the operating point. This problem is addressed via a hybrid control law consisting of two robust controllers and a robust switch between them activated by the set point change. The controllers are designed to cover the corresponding half-ranges of the full operating range. This permits attainment of the desired overall performance as well as reduction of modeling uncertainty induced by the operating point change to approximately 25% of that associated with the previous designs. Robust switching is accomplished through a novel hybrid mode of behavior—robustly controlled discrete transition. The latter mode is produced through realizing that the off-line transfer speedup suggested by and (2005, “ The L2(l2) bumpless Transfer Problem for Linear Parts: Its Definition and Solution,” Automatica, 41, pp. 1273–1280) can be taken to the limit and incorporating the result into a robust bumpless transfer technique recently developed by the authors. As demonstrated by simulation results, the proposed strategy provides an adequate solution to the problem of robust boiler/turbine unit performance over the full operating range. This fact combined with numerical algorithm tractability, relative ease of its design, its insensitivity to implementation nonidealities, and accompanying identification methodology for nominal model generation makes it a viable candidate for industrial acceptance. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Nonminimum-phase phenomenon of PEM fuel cell membrane humidifiers / Chen, Dongmei in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Titre : Nonminimum-phase phenomenon of PEM fuel cell membrane humidifiers Type de document : texte imprimé Auteurs : Chen, Dongmei, Auteur ; Huei Peng, Auteur Année de publication : 2008 Article en page(s) : 9 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : air  flow;  humidifiers;  membranes;  vapors;  temperature;  water;  fuel  cells Résumé : A membrane-based humidifier that uses cooling water of a fuel cell system to humidify the inlet air is modeled and analyzed in this paper. This four-state lumped model is simple and yet captures the humidification behavior accurately. A peculiar characteristic of this system is the fact that it exhibits nonminimum-phase (NMP) behavior. The reason the NMP behavior exists and the effect of system parameters on the location of the NMP zero are analyzed. A proportional control algorithm is proposed to reject the effect of system disturbances, and a feed-forward algorithm is developed to ensure proper humidifier operation under air flow rate changes. Because the NMP zero exists in the disturbance-to-output loop, the proposed algorithm was found to successfully eliminate the undershoot phenomena associated with the NMP zero. However, the disturbance-to-output loop is coupled with input-to-output loop, and the NMP zero could affect the feedback control design. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Nonminimum-phase phenomenon of PEM fuel cell membrane humidifiers [texte imprimé] / Chen, Dongmei, Auteur ; Huei Peng, Auteur . - 2008 . - 9 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Mots-clés : air  flow;  humidifiers;  membranes;  vapors;  temperature;  water;  fuel  cells Résumé : A membrane-based humidifier that uses cooling water of a fuel cell system to humidify the inlet air is modeled and analyzed in this paper. This four-state lumped model is simple and yet captures the humidification behavior accurately. A peculiar characteristic of this system is the fact that it exhibits nonminimum-phase (NMP) behavior. The reason the NMP behavior exists and the effect of system parameters on the location of the NMP zero are analyzed. A proportional control algorithm is proposed to reject the effect of system disturbances, and a feed-forward algorithm is developed to ensure proper humidifier operation under air flow rate changes. Because the NMP zero exists in the disturbance-to-output loop, the proposed algorithm was found to successfully eliminate the undershoot phenomena associated with the NMP zero. However, the disturbance-to-output loop is coupled with input-to-output loop, and the NMP zero could affect the feedback control design. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

A simple structure for bilateral transparent teleoperation systems with time delay / Alireza Alfi in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Titre : A simple structure for bilateral transparent teleoperation systems with time delay Type de document : texte imprimé Auteurs : Alireza Alfi, Auteur ; Farrokhi, Mohammad, Auteur Année de publication : 2008 Article en page(s) : 9 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : stability;  control  equipment;  delays;  transparency;  closed  loop  systems;  design;  channels  (hydraulic  engineering) Résumé : This paper presents a simple structure design for bilateral teleoperation systems with uncertainties in time delay in communication channel. The goal is to achieve complete transparency and robust stability for the closed-loop system. For transparency, two local controllers are designed for the bilateral teleoperation systems. One local controller is responsible for tracking the master commands, and the other one is in charge of force tracking as well as guaranteeing the stability of the closed-loop system in the presence of uncertainties in time delay. The stability analysis will be shown analytically for two cases: (I) the possibly stability and (II) the intrinsically stability. Moreover, in Case II, in order to generate the proper inputs for the master controller in the presence of uncertainties in time delay, an adaptive finite impulse response (FIR) filter is designed to estimate the time delay. The advantages of the proposed method are threefold: (1) stability of the closed-loop system is guaranteed under some mild conditions, (2) the whole system is transparent, and (3) design of the local controllers is simple. Simulation results show good performance of the proposed method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] A simple structure for bilateral transparent teleoperation systems with time delay [texte imprimé] / Alireza Alfi, Auteur ; Farrokhi, Mohammad, Auteur . - 2008 . - 9 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 9 p. Mots-clés : stability;  control  equipment;  delays;  transparency;  closed  loop  systems;  design;  channels  (hydraulic  engineering) Résumé : This paper presents a simple structure design for bilateral teleoperation systems with uncertainties in time delay in communication channel. The goal is to achieve complete transparency and robust stability for the closed-loop system. For transparency, two local controllers are designed for the bilateral teleoperation systems. One local controller is responsible for tracking the master commands, and the other one is in charge of force tracking as well as guaranteeing the stability of the closed-loop system in the presence of uncertainties in time delay. The stability analysis will be shown analytically for two cases: (I) the possibly stability and (II) the intrinsically stability. Moreover, in Case II, in order to generate the proper inputs for the master controller in the presence of uncertainties in time delay, an adaptive finite impulse response (FIR) filter is designed to estimate the time delay. The advantages of the proposed method are threefold: (1) stability of the closed-loop system is guaranteed under some mild conditions, (2) the whole system is transparent, and (3) design of the local controllers is simple. Simulation results show good performance of the proposed method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Robust unknown input observer for nonlinear systems and its application to fault detection and isolation / S. Mondal in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 5 p. Titre : Robust unknown input observer for nonlinear systems and its application to fault detection and isolation Type de document : texte imprimé Auteurs : S. Mondal, Auteur ; G. Chakraborty, Auteur ; K. Bhattacharyya, Auteur Année de publication : 2008 Article en page(s) : 5 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : theorems  (mathematics);  noise  (sound);  actuators;  nonlinear  systems;  flaw  detection;  algorithms;  linear  matrix  inequalities Résumé : A robust unknown input observer for a nonlinear system whose nonlinear function satisfies the Lipschitz condition is designed based on linear matrix inequality approach. Both noise and uncertainties are taken into account in deriving the observer. A component fault detection and isolation scheme based on these observers is proposed. The effectiveness of the observer and the fault diagnosis scheme is shown by applying them for component fault diagnosis of an electrohydraulic actuator. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Robust unknown input observer for nonlinear systems and its application to fault detection and isolation [texte imprimé] / S. Mondal, Auteur ; G. Chakraborty, Auteur ; K. Bhattacharyya, Auteur . - 2008 . - 5 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 5 p. Mots-clés : theorems  (mathematics);  noise  (sound);  actuators;  nonlinear  systems;  flaw  detection;  algorithms;  linear  matrix  inequalities Résumé : A robust unknown input observer for a nonlinear system whose nonlinear function satisfies the Lipschitz condition is designed based on linear matrix inequality approach. Both noise and uncertainties are taken into account in deriving the observer. A component fault detection and isolation scheme based on these observers is proposed. The effectiveness of the observer and the fault diagnosis scheme is shown by applying them for component fault diagnosis of an electrohydraulic actuator. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

Memoryless adaptive controller design for uncertain polynomial systems with multiple time delays / Chang-Chun Hua in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 n°4 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 7 p. Titre : Memoryless adaptive controller design for uncertain polynomial systems with multiple time delays Type de document : texte imprimé Auteurs : Chang-Chun Hua, Auteur ; Qing-Guo Wang, Auteur ; Peng, Shi, Auteur Année de publication : 2008 Article en page(s) : 7 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : control  equipment;  design;  delays;  polynomials;  closed  loop  systems Résumé : The stabilization problem is investigated for a class of uncertain systems with multiple time-varying delays. The considered system includes the uncertain nonlinear time delay functions, whose bounds are in the form of polynomial-type functions with unknown coefficients. The system is decomposed into two subsystems based on the input matrix. For the first subsystem, a time delay dependent linear virtual control input is constructed. Then, a memoryless state feedback controller is designed based on backstepping method. By employing new Lyapunov–Krasovskii functional, we show that the closed-loop system is exponentially stable. Finally, simulations are conducted to verify the effectiveness of the proposed method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Memoryless adaptive controller design for uncertain polynomial systems with multiple time delays [texte imprimé] / Chang-Chun Hua, Auteur ; Qing-Guo Wang, Auteur ; Peng, Shi, Auteur . - 2008 . - 7 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 n°4 (Juillet 2008) . - 7 p. Mots-clés : control  equipment;  design;  delays;  polynomials;  closed  loop  systems Résumé : The stabilization problem is investigated for a class of uncertain systems with multiple time-varying delays. The considered system includes the uncertain nonlinear time delay functions, whose bounds are in the form of polynomial-type functions with unknown coefficients. The system is decomposed into two subsystems based on the input matrix. For the first subsystem, a time delay dependent linear virtual control input is constructed. Then, a memoryless state feedback controller is designed based on backstepping method. By employing new Lyapunov–Krasovskii functional, we show that the closed-loop system is exponentially stable. Finally, simulations are conducted to verify the effectiveness of the proposed method. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]

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