Implementation of a Physiologically Identified PD Feedback Controller for Regulating the Active Ankle Torque during Quiet Stance. Vette, A. H., Masani, K., & Popovic, M. R abstract bibtex Our studies have recently demonstrated that a proportional and derivative (PD) feedback controller, which takes advantage of the body’s position and velocity information to regulate balance during quiet standing, can compensate for long neurological time delays and generate a control command that precedes body sway by 100 to 200 ms. Furthermore, PD gain pairs were identified that ensure a robust system behavior and at the same time generate dynamic responses as observed in quiet standing experiments with able-bodied subjects. The purpose of the present study was to experimentally verify that the PD controller identified in our previous study can: 1) regulate the active ankle torque to stabilize the body during quiet standing in spite of long neurological time delays; and 2) generate system dynamics, i.e., a motor command and body sway fluctuation, that successfully mimic those of the physiologic system of quiet standing. Our real-time closed-loop feedback circuit consisted of a center of mass position sensor and a functional electrical stimulator that elicited contractions of the plantar flexors as determined by the aforementioned PD controller. The control system regulated upright stance of a subject who was partially de-afferented and -efferented due to a neurological disorder called von Hippel Lindau Syndrome (McCormick Grade III). While the subject was able to generate a motor command for the ankle joints, he could not regulate the resulting torque sufficiently due to a lack of sensory feedback. It is important to mention that a time delay was included in the closed-loop circuit of the PD controller to mimic the actual neurological time delay observed in able-bodied individuals. The experimental results of this case study suggest that the proposed PD controller in combination with a functional electrical stimulation system can regulate the active ankle torque during quiet stance and generate the same system dynamics as observed in healthy individuals. While these findings do not imply that the CNS actually applies a PD-like control strategy to regulate balance, they suggest that it is at least theoretically possible.
@article{vette_implementation_nodate,
title = {Implementation of a {Physiologically} {Identified} {PD} {Feedback} {Controller} for {Regulating} the {Active} {Ankle} {Torque} during {Quiet} {Stance}},
copyright = {All rights reserved},
abstract = {Our studies have recently demonstrated that a proportional and derivative (PD) feedback
controller, which takes advantage of the body’s position and velocity information to regulate
balance during quiet standing, can compensate for long neurological time delays and generate a
control command that precedes body sway by 100 to 200 ms. Furthermore, PD gain pairs were
identified that ensure a robust system behavior and at the same time generate dynamic responses
as observed in quiet standing experiments with able-bodied subjects. The purpose of the present
study was to experimentally verify that the PD controller identified in our previous study can: 1)
regulate the active ankle torque to stabilize the body during quiet standing in spite of long
neurological time delays; and 2) generate system dynamics, i.e., a motor command and body
sway fluctuation, that successfully mimic those of the physiologic system of quiet standing. Our
real-time closed-loop feedback circuit consisted of a center of mass position sensor and a
functional electrical stimulator that elicited contractions of the plantar flexors as determined by
the aforementioned PD controller. The control system regulated upright stance of a subject who
was partially de-afferented and -efferented due to a neurological disorder called von Hippel
Lindau Syndrome (McCormick Grade III). While the subject was able to generate a motor
command for the ankle joints, he could not regulate the resulting torque sufficiently due to a lack
of sensory feedback. It is important to mention that a time delay was included in the closed-loop
circuit of the PD controller to mimic the actual neurological time delay observed in able-bodied
individuals. The experimental results of this case study suggest that the proposed PD controller
in combination with a functional electrical stimulation system can regulate the active ankle
torque during quiet stance and generate the same system dynamics as observed in healthy
individuals. While these findings do not imply that the CNS actually applies a PD-like control
strategy to regulate balance, they suggest that it is at least theoretically possible.},
author = {Vette, Albert H. and Masani, Kei and Popovic, Milos R},
}
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R"],"year":null,"bibtype":"article","biburl":"https://api.zotero.org/users/4249728/collections/NJBK2WVC/items?key=gYm8ZvhzAxJayegPrrP0poQ7&format=bibtex&limit=100","bibdata":{"bibtype":"article","type":"article","title":"Implementation of a Physiologically Identified PD Feedback Controller for Regulating the Active Ankle Torque during Quiet Stance","copyright":"All rights reserved","abstract":"Our studies have recently demonstrated that a proportional and derivative (PD) feedback controller, which takes advantage of the body’s position and velocity information to regulate balance during quiet standing, can compensate for long neurological time delays and generate a control command that precedes body sway by 100 to 200 ms. Furthermore, PD gain pairs were identified that ensure a robust system behavior and at the same time generate dynamic responses as observed in quiet standing experiments with able-bodied subjects. The purpose of the present study was to experimentally verify that the PD controller identified in our previous study can: 1) regulate the active ankle torque to stabilize the body during quiet standing in spite of long neurological time delays; and 2) generate system dynamics, i.e., a motor command and body sway fluctuation, that successfully mimic those of the physiologic system of quiet standing. Our real-time closed-loop feedback circuit consisted of a center of mass position sensor and a functional electrical stimulator that elicited contractions of the plantar flexors as determined by the aforementioned PD controller. The control system regulated upright stance of a subject who was partially de-afferented and -efferented due to a neurological disorder called von Hippel Lindau Syndrome (McCormick Grade III). While the subject was able to generate a motor command for the ankle joints, he could not regulate the resulting torque sufficiently due to a lack of sensory feedback. It is important to mention that a time delay was included in the closed-loop circuit of the PD controller to mimic the actual neurological time delay observed in able-bodied individuals. The experimental results of this case study suggest that the proposed PD controller in combination with a functional electrical stimulation system can regulate the active ankle torque during quiet stance and generate the same system dynamics as observed in healthy individuals. While these findings do not imply that the CNS actually applies a PD-like control strategy to regulate balance, they suggest that it is at least theoretically possible.","author":[{"propositions":[],"lastnames":["Vette"],"firstnames":["Albert","H."],"suffixes":[]},{"propositions":[],"lastnames":["Masani"],"firstnames":["Kei"],"suffixes":[]},{"propositions":[],"lastnames":["Popovic"],"firstnames":["Milos","R"],"suffixes":[]}],"bibtex":"@article{vette_implementation_nodate,\n\ttitle = {Implementation of a {Physiologically} {Identified} {PD} {Feedback} {Controller} for {Regulating} the {Active} {Ankle} {Torque} during {Quiet} {Stance}},\n\tcopyright = {All rights reserved},\n\tabstract = {Our studies have recently demonstrated that a proportional and derivative (PD) feedback \ncontroller, which takes advantage of the body’s position and velocity information to regulate \nbalance during quiet standing, can compensate for long neurological time delays and generate a \ncontrol command that precedes body sway by 100 to 200 ms. Furthermore, PD gain pairs were \nidentified that ensure a robust system behavior and at the same time generate dynamic responses \nas observed in quiet standing experiments with able-bodied subjects. The purpose of the present \nstudy was to experimentally verify that the PD controller identified in our previous study can: 1) \nregulate the active ankle torque to stabilize the body during quiet standing in spite of long \nneurological time delays; and 2) generate system dynamics, i.e., a motor command and body \nsway fluctuation, that successfully mimic those of the physiologic system of quiet standing. Our \nreal-time closed-loop feedback circuit consisted of a center of mass position sensor and a \nfunctional electrical stimulator that elicited contractions of the plantar flexors as determined by \nthe aforementioned PD controller. The control system regulated upright stance of a subject who \nwas partially de-afferented and -efferented due to a neurological disorder called von Hippel\nLindau Syndrome (McCormick Grade III). While the subject was able to generate a motor \ncommand for the ankle joints, he could not regulate the resulting torque sufficiently due to a lack \nof sensory feedback. It is important to mention that a time delay was included in the closed-loop \ncircuit of the PD controller to mimic the actual neurological time delay observed in able-bodied \nindividuals. The experimental results of this case study suggest that the proposed PD controller \nin combination with a functional electrical stimulation system can regulate the active ankle \ntorque during quiet stance and generate the same system dynamics as observed in healthy \nindividuals. While these findings do not imply that the CNS actually applies a PD-like control \nstrategy to regulate balance, they suggest that it is at least theoretically possible.},\n\tauthor = {Vette, Albert H. and Masani, Kei and Popovic, Milos R},\n}\n\n","author_short":["Vette, A. H.","Masani, K.","Popovic, M. R"],"key":"vette_implementation_nodate","id":"vette_implementation_nodate","bibbaseid":"vette-masani-popovic-implementationofaphysiologicallyidentifiedpdfeedbackcontrollerforregulatingtheactiveankletorqueduringquietstance","role":"author","urls":{},"metadata":{"authorlinks":{}},"downloads":0},"search_terms":["implementation","physiologically","identified","feedback","controller","regulating","active","ankle","torque","during","quiet","stance","vette","masani","popovic"],"keywords":[],"authorIDs":[],"dataSources":["xzHB9k8foQ3ZKJjjS"]}