Documents disponibles écrits par cet auteur

Application of combined feedforward and feedback controller with shaped input to benchmark problem / Young Joo Shin in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 132 N° 2 (Mars/Avril 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 2 (Mars/Avril 2010) . - 08 p. Titre : Application of combined feedforward and feedback controller with shaped input to benchmark problem Type de document : texte imprimé Auteurs : Young Joo Shin, Auteur ; Peter H. Meckl, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Systèmes dynamiques Langues : Anglais (eng) Mots-clés : Control  system  synthesis  Feedback  Feedforward  Robust  control  Springs  (mechanical)  Vibration  control Index. décimale : 629.8 Résumé : Benchmark problems have been used to evaluate the performance of a variety of robust control design methodologies by many control engineers over the past 2 decades. A benchmark is a simple but meaningful problem to highlight the advantages and disadvantages of different control strategies. This paper verifies the performance of a new control strategy, which is called combined feedforward and feedback control with shaped input (CFFS), through a benchmark problem applied to a two-mass-spring system. CFFS, which consists of feedback and feedforward controllers and shaped input, can achieve high performance with a simple controller design. This control strategy has several unique characteristics. First, the shaped input is designed to extract energy from the flexible modes, which means that a simpler feedback control design based on a rigid-body model can be used. In addition, only a single frequency must be attenuated to reduce residual vibration of both masses. Second, only the dynamics between control force and the first mass need to be considered in designing both feedback and feedforward controllers. The proposed control strategy is applied to a benchmark problem and its performance is compared with that obtained using two alternative control strategies. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...] [article] Application of combined feedforward and feedback controller with shaped input to benchmark problem [texte imprimé] / Young Joo Shin, Auteur ; Peter H. Meckl, Auteur . - 2010 . - 08 p. Systèmes dynamiques Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 132 N° 2 (Mars/Avril 2010) . - 08 p. Mots-clés : Control  system  synthesis  Feedback  Feedforward  Robust  control  Springs  (mechanical)  Vibration  control Index. décimale : 629.8 Résumé : Benchmark problems have been used to evaluate the performance of a variety of robust control design methodologies by many control engineers over the past 2 decades. A benchmark is a simple but meaningful problem to highlight the advantages and disadvantages of different control strategies. This paper verifies the performance of a new control strategy, which is called combined feedforward and feedback control with shaped input (CFFS), through a benchmark problem applied to a two-mass-spring system. CFFS, which consists of feedback and feedforward controllers and shaped input, can achieve high performance with a simple controller design. This control strategy has several unique characteristics. First, the shaped input is designed to extract energy from the flexible modes, which means that a simpler feedback control design based on a rigid-body model can be used. In addition, only a single frequency must be attenuated to reduce residual vibration of both masses. Second, only the dynamics between control force and the first mass need to be considered in designing both feedback and feedforward controllers. The proposed control strategy is applied to a benchmark problem and its performance is compared with that obtained using two alternative control strategies. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA00013200 [...]

Controller design procedure for two-mass systems with single flexible mode / Young Joo Shin in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 N° 3 (Mai/Juin 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N° 3 (Mai/Juin 2008) . - 13 p. Titre : Controller design procedure for two-mass systems with single flexible mode Type de document : texte imprimé Auteurs : Young Joo Shin, Auteur ; Peter H. Meckl, Auteur Année de publication : 2010 Article en page(s) : 13 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : Two-mass  systems;  control  strategy;  feedback  controller;  feedforward  controller Résumé : Many manufacturing machines must execute motions as quickly as possible to achieve profitable high-volume production. Most of them exhibit some flexibility, which makes the settling time longer and controller design difficult. This paper develops a control strategy that combines feedforward and feedback control with command shaping for systems with collocated actuator and sensor. First, a feedback controller is designed to increase damping and eliminate steady-state error. Next, an appropriate reference profile is generated using command-shaping techniques to ensure fast point-to-point motions with minimum residual vibration. Finally, a feedforward controller is designed to speed up the transient response. The proposed proportional-integral-derivative (PID) controller design ensures that two important resonant frequencies nearly match, making the design of the input commands much simpler. The resulting control strategy is successfully demonstrated for a generic dimensionless system that incorporates some modeling errors to assess robustness. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/mobile/article.aspx?article [...] [article] Controller design procedure for two-mass systems with single flexible mode [texte imprimé] / Young Joo Shin, Auteur ; Peter H. Meckl, Auteur . - 2010 . - 13 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N° 3 (Mai/Juin 2008) . - 13 p. Mots-clés : Two-mass  systems;  control  strategy;  feedback  controller;  feedforward  controller Résumé : Many manufacturing machines must execute motions as quickly as possible to achieve profitable high-volume production. Most of them exhibit some flexibility, which makes the settling time longer and controller design difficult. This paper develops a control strategy that combines feedforward and feedback control with command shaping for systems with collocated actuator and sensor. First, a feedback controller is designed to increase damping and eliminate steady-state error. Next, an appropriate reference profile is generated using command-shaping techniques to ensure fast point-to-point motions with minimum residual vibration. Finally, a feedforward controller is designed to speed up the transient response. The proposed proportional-integral-derivative (PID) controller design ensures that two important resonant frequencies nearly match, making the design of the input commands much simpler. The resulting control strategy is successfully demonstrated for a generic dimensionless system that incorporates some modeling errors to assess robustness. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/mobile/article.aspx?article [...]

Model-independent control of a flexible-joint robot manipulator / Withit Chatlatanagulchai 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) . - 10 p. Titre : Model-independent control of a flexible-joint robot manipulator Type de document : texte imprimé Auteurs : Withit Chatlatanagulchai, Auteur ; Peter H. Meckl, Auteur Année de publication : 2009 Article en page(s) : 10 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : manipulator;  joint  flexibility Résumé : Flexibility at the joint of a manipulator is an intrinsic property. Even “rigid-joint” robots, in fact, possess a certain amount of flexibility. Previous experiments confirmed that joint flexibility should be explicitly included in the model when designing a high-performance controller for a manipulator because the flexibility, if not dealt with, can excite system natural frequencies and cause severe damage. However, control design for a flexible-joint robot manipulator is still an open problem. Besides being described by a complicated system model for which the passivity property does not hold, the manipulator is also underactuated, that is, the control input does not drive the link directly, but through the flexible dynamics. Our work offers another possible solution to this open problem. We use three-layer neural networks to represent the system model. Their weights are adapted in real time and from scratch, which means we do not need the mathematical model of the robot in our control algorithm. All uncertainties are handled by variable-structure control. Backstepping structure allows input efforts to be applied to each subsystem where they are needed. Control laws to adjust all adjustable parameters are devised using Lyapunov’s second method to ensure that error trajectories are globally uniformly ultimately bounded. We present two state-feedback schemes: first, when neural networks are used to represent the unknown plant, and second, when neural networks are used to represent the unknown parts of the control laws. In the former case, we also design an observer to enable us to design a control law using only output signals—the link positions. We use simulations to compare our algorithms with some other well-known techniques. We use experiments to demonstrate the practicality of our algorithms. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...] [article] Model-independent control of a flexible-joint robot manipulator [texte imprimé] / Withit Chatlatanagulchai, Auteur ; Peter H. Meckl, Auteur . - 2009 . - 10 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 131 N° 4 (Juillet 2009) . - 10 p. Mots-clés : manipulator;  joint  flexibility Résumé : Flexibility at the joint of a manipulator is an intrinsic property. Even “rigid-joint” robots, in fact, possess a certain amount of flexibility. Previous experiments confirmed that joint flexibility should be explicitly included in the model when designing a high-performance controller for a manipulator because the flexibility, if not dealt with, can excite system natural frequencies and cause severe damage. However, control design for a flexible-joint robot manipulator is still an open problem. Besides being described by a complicated system model for which the passivity property does not hold, the manipulator is also underactuated, that is, the control input does not drive the link directly, but through the flexible dynamics. Our work offers another possible solution to this open problem. We use three-layer neural networks to represent the system model. Their weights are adapted in real time and from scratch, which means we do not need the mathematical model of the robot in our control algorithm. All uncertainties are handled by variable-structure control. Backstepping structure allows input efforts to be applied to each subsystem where they are needed. Control laws to adjust all adjustable parameters are devised using Lyapunov’s second method to ensure that error trajectories are globally uniformly ultimately bounded. We present two state-feedback schemes: first, when neural networks are used to represent the unknown plant, and second, when neural networks are used to represent the unknown parts of the control laws. In the former case, we also design an observer to enable us to design a control law using only output signals—the link positions. We use simulations to compare our algorithms with some other well-known techniques. We use experiments to demonstrate the practicality of our algorithms. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Issue.aspx?issueID=26497&di [...]

Optimal parameter estimation for long-term prediction in the presence of model mismatch / Ryan Sangjun Lee in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 134 N° 4 (Juillet 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 4 (Juillet 2012) . - 16 p. Titre : Optimal parameter estimation for long-term prediction in the presence of model mismatch Type de document : texte imprimé Auteurs : Ryan Sangjun Lee, Auteur ; Gregery T. Buzzard, Auteur ; Peter H. Meckl, Auteur Année de publication : 2012 Article en page(s) : 16 p. Note générale : Dynamic systems Langues : Anglais (eng) Mots-clés : Nonlinear  multi-input  multi-output  (MIMO)  systems  Least-squares  minimization  Long-term  prediction  error  MIMO  nonlinear  systems. Index. décimale : 629.8 Résumé : For nonlinear multi-input multi-output (MIMO) systems such as multilink robotic manipulators, finding a correct, physically derived model structure is almost impossible, so that significant model mismatch is nearly inevitable. Moreover, in the presence of model mismatch, the use of least-squares minimization of the one-step-ahead prediction error (residual error) to estimate unknown parameters in a given model structure often leads to model predictions that are extremely inaccurate beyond a short time interval. In this paper, we develop a method for optimal parameter estimation for accurate long-term prediction models in the presence of significant model mismatch in practice. For many practical cases, where a correct model and the correct number of degrees of freedom for a given model structure are unknown, we combine the use of long-term prediction error with frequency-based regularization to produce more accurate long-term prediction models for actual MIMO nonlinear systems. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000004 [...] [article] Optimal parameter estimation for long-term prediction in the presence of model mismatch [texte imprimé] / Ryan Sangjun Lee, Auteur ; Gregery T. Buzzard, Auteur ; Peter H. Meckl, Auteur . - 2012 . - 16 p. Dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 134 N° 4 (Juillet 2012) . - 16 p. Mots-clés : Nonlinear  multi-input  multi-output  (MIMO)  systems  Least-squares  minimization  Long-term  prediction  error  MIMO  nonlinear  systems. Index. décimale : 629.8 Résumé : For nonlinear multi-input multi-output (MIMO) systems such as multilink robotic manipulators, finding a correct, physically derived model structure is almost impossible, so that significant model mismatch is nearly inevitable. Moreover, in the presence of model mismatch, the use of least-squares minimization of the one-step-ahead prediction error (residual error) to estimate unknown parameters in a given model structure often leads to model predictions that are extremely inaccurate beyond a short time interval. In this paper, we develop a method for optimal parameter estimation for accurate long-term prediction models in the presence of significant model mismatch in practice. For many practical cases, where a correct model and the correct number of degrees of freedom for a given model structure are unknown, we combine the use of long-term prediction error with frequency-based regularization to produce more accurate long-term prediction models for actual MIMO nonlinear systems. DEWEY : 629.8 ISSN : 0022-0434 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JDSMAA000134000004 [...]

The application of command shaping to the tracking problem / Michael C. Reynolds in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 N° 3 (Mai/Juin 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N° 3 (Mai/Juin 2008) . - 12 p. Titre : The application of command shaping to the tracking problem Type de document : texte imprimé Auteurs : Michael C. Reynolds, Auteur ; Peter H. Meckl, Auteur Année de publication : 2010 Article en page(s) : 12 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : trajectory  tracking;  command  shaping;  optimal  input Résumé : This work presents a novel technique for the solution of an optimal input for trajectory tracking. Many researchers have documented the performance advantages of command shaping, which focuses on the design of an optimal input. Nearly all research in command shaping has been centered on the point-to-point motion control problem. However, tracking problems are also an important application of control theory. The proposed optimal tracking technique extends the point-to-point motion control problem to the solution of the tracking problem. Thus, two very different problems are brought into one solution scheme. The technique uses tolerances on trajectory following to meet constraints and minimize either maneuver time or input energy. A major advantage of the technique is that hard physical constraints such as acceleration or allowable tracking error can be directly constrained. Previous methods to perform such a task involved using various weightings that lack physical meaning. The optimal tracking technique allows for fast and efficient exploration of the solution space for motion control. A solution verification technique is presented and some examples are included to demonstrate the technique. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Mobile/article.aspx?article [...] [article] The application of command shaping to the tracking problem [texte imprimé] / Michael C. Reynolds, Auteur ; Peter H. Meckl, Auteur . - 2010 . - 12 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N° 3 (Mai/Juin 2008) . - 12 p. Mots-clés : trajectory  tracking;  command  shaping;  optimal  input Résumé : This work presents a novel technique for the solution of an optimal input for trajectory tracking. Many researchers have documented the performance advantages of command shaping, which focuses on the design of an optimal input. Nearly all research in command shaping has been centered on the point-to-point motion control problem. However, tracking problems are also an important application of control theory. The proposed optimal tracking technique extends the point-to-point motion control problem to the solution of the tracking problem. Thus, two very different problems are brought into one solution scheme. The technique uses tolerances on trajectory following to meet constraints and minimize either maneuver time or input energy. A major advantage of the technique is that hard physical constraints such as acceleration or allowable tracking error can be directly constrained. Previous methods to perform such a task involved using various weightings that lack physical meaning. The optimal tracking technique allows for fast and efficient exploration of the solution space for motion control. A solution verification technique is presented and some examples are included to demonstrate the technique. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/Mobile/article.aspx?article [...]