Dissertation•
Formation de la trajectoire pour des tâches supra-posturales : modélisation et expérimentation
01 Jan 2004-
TL;DR: In this paper, a modele de formation de la trajectoire capable of decrire le mode de fonctionnement du systeme and determiner the variable, which lui etait associee, garante du controle de l'equilibre.
Abstract: Le premier objectif de ce travail etait de developper un modele de formation de la trajectoire capable d'une part de decrire le mode de fonctionnement du systeme (definition d'une fonction objective) et d'autre part de determiner la variable, qui lui etait associee, garante du controle de l'equilibre. La theorie de l'optimisation dynamique a donc ete utilisee dans le but de favoriser la comprehension des principes d'organisation et de production de comportements moteurs diriges vers un but. Le second objectif a ete de tester les capacites de prediction de ce modele pour d'eventuels changements de strategie posturale en fonction des contraintes de la tâche a realiser. La validation de ce modele de formation de la trajectoire s'est concretisee par son application a l'analyse de la coordination pluri-articulaire pour un mouvement d'elevation des bras en station bipedique et pour une tâche de poursuite visuelle avec la tete. Le mode de fonctionnement du systeme serait alors relatif a la dynamique du systeme musculo-squelettique et le maintien de l'equilibre serait controler par una variable d'ordre dynamique. D'autre part, l'analyse des facteurs dynamiques d'une tâche de poursuite visuelle rend compte des causes sous-jacentes aux changements de strategies posturales.
Citations
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01 Dec 2008
TL;DR: The proposed closed-loop controller captures the complex postural behaviors observed in humans and can be used to implement efficient and simple balance control principles in humanoids.
Abstract: This paper models recent data in the field of postural coordination showing the existence of self-organized postural states, and transition between them, underlying supra-postural tracking movements. The proposed closed-loop controller captures the complex postural behaviors observed in humans and can be used to implement efficient and simple balance control principles in humanoids.
10 citations
Cites result from "Formation de la trajectoire pour de..."
...The hip amplitude is larger than the ankle amplitude for the anti-phase mode as mentioned in [11], [10]....
[...]
...[12] These observations were observed for all participants and are in accordance with [9], [5], [11], even though the actual transition frequency and joint amplitudes depend on the specific subject body type....
[...]
Dissertation•
10 Dec 2015
TL;DR: This thesis addresses inverse optimal control problems (IOCP) to find the cost functions for which the human motions are optimal, and proposed a new approach to solving the IOCP, in a bounded error framework.
Abstract: This thesis addresses inverse optimal control problems (IOCP) to find the cost functions for which the human motions are optimal. Assuming that the human motion observations are perfect, while the human motor control process is imperfect, we propose an approximately optimal control algorithm. By applying our algorithm to the human motion observations collected for: the human arm trajectories during an industrial screwing task, a postural coordination in a visual tracking task and a walking gait initialization task, we performed an open loop analysis. For the three cases, our algorithm returned the cost functions which better fit these data, while approximately satisfying the Karush-Kuhn-Tucker (KKT) optimality conditions. Our algorithm offers a nice computational time for all cases, providing an opportunity for its use in online applications. For the visual tracking task, we investigated a closed loop modeling with two PD feedback loops. With artificial data, we obtained consistent results in terms of feedback gains’ trends and criteria exhibited by our algorithm for the visual tracking task. In the second part of our work, we proposed a new approach to solving the IOCP, in a bounded error framework. In this approach, we assume that the human motor control process is perfect while the observations have errors and uncertainties acting on them, being imperfect. The errors are bounded with known bounds, otherwise unknown. Our approach finds the convex hull of the set of feasible cost function with a certainty that it includes the true solution. We numerically guaranteed this using interval analysis tools.
9 citations
Cites background or result from "Formation de la trajectoire pour de..."
...This strong reduction of the ankle amplitude is typical for the human phase transition [88, 79, 89]....
[...]
...These observations hold for all participants and are in accordance with [88, 91, 89], even though the actual transition frequency and joint amplitudes depend on the specific subject body type....
[...]
...The hip amplitude is larger than the ankle amplitude for the anti-phase mode as mentioned in [88, 79, 89]....
[...]
15 Dec 2009
TL;DR: This work proposes to identify spindle reflex equivalent feedback gains for several target's frequency values in motor-control litterature, where spindle feedback gains are scaled by the central nervous system to adapt muscle stiffness depending on the postural task.
Abstract: A closed-loop model with actuator dynamics and sensory feedback has been developed to capture the complex postural behaviors observed in a human head tracking task. In motor-control litterature, spindle feedback gains are scaled by the central nervous system to adapt muscle stiffness depending on the postural task. We propose to identify spindle reflex equivalent feedback gains for several target's frequency values. Comparison with experimental results on human shows the relevance of this modeling, since our musculoskeletal model is able to exhibit reasonably well the behavioral invariants observed in human postures.
7 citations
Cites background or result from "Formation de la trajectoire pour de..."
...These observations hold for all participants and are in accordance with [11], [1], [13], even though the actual transition frequency and joint amplitudes depend on the specific subject body type....
[...]
...This strong reduction of the ankle amplitude is typical of human phase transition [11], [12], [13]....
[...]
...The hip amplitude is larger than the ankle amplitude for the anti-phase mode as mentioned in [11], [12], [13]....
[...]
References
More filters
01 Dec 2008
TL;DR: The proposed closed-loop controller captures the complex postural behaviors observed in humans and can be used to implement efficient and simple balance control principles in humanoids.
Abstract: This paper models recent data in the field of postural coordination showing the existence of self-organized postural states, and transition between them, underlying supra-postural tracking movements. The proposed closed-loop controller captures the complex postural behaviors observed in humans and can be used to implement efficient and simple balance control principles in humanoids.
10 citations
Dissertation•
10 Dec 2015
TL;DR: This thesis addresses inverse optimal control problems (IOCP) to find the cost functions for which the human motions are optimal, and proposed a new approach to solving the IOCP, in a bounded error framework.
Abstract: This thesis addresses inverse optimal control problems (IOCP) to find the cost functions for which the human motions are optimal. Assuming that the human motion observations are perfect, while the human motor control process is imperfect, we propose an approximately optimal control algorithm. By applying our algorithm to the human motion observations collected for: the human arm trajectories during an industrial screwing task, a postural coordination in a visual tracking task and a walking gait initialization task, we performed an open loop analysis. For the three cases, our algorithm returned the cost functions which better fit these data, while approximately satisfying the Karush-Kuhn-Tucker (KKT) optimality conditions. Our algorithm offers a nice computational time for all cases, providing an opportunity for its use in online applications. For the visual tracking task, we investigated a closed loop modeling with two PD feedback loops. With artificial data, we obtained consistent results in terms of feedback gains’ trends and criteria exhibited by our algorithm for the visual tracking task. In the second part of our work, we proposed a new approach to solving the IOCP, in a bounded error framework. In this approach, we assume that the human motor control process is perfect while the observations have errors and uncertainties acting on them, being imperfect. The errors are bounded with known bounds, otherwise unknown. Our approach finds the convex hull of the set of feasible cost function with a certainty that it includes the true solution. We numerically guaranteed this using interval analysis tools.
9 citations
15 Dec 2009
TL;DR: This work proposes to identify spindle reflex equivalent feedback gains for several target's frequency values in motor-control litterature, where spindle feedback gains are scaled by the central nervous system to adapt muscle stiffness depending on the postural task.
Abstract: A closed-loop model with actuator dynamics and sensory feedback has been developed to capture the complex postural behaviors observed in a human head tracking task. In motor-control litterature, spindle feedback gains are scaled by the central nervous system to adapt muscle stiffness depending on the postural task. We propose to identify spindle reflex equivalent feedback gains for several target's frequency values. Comparison with experimental results on human shows the relevance of this modeling, since our musculoskeletal model is able to exhibit reasonably well the behavioral invariants observed in human postures.
7 citations