Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing
By assuming that the human body rotates primarily around the ankle joint in the sagittal plane, the human body has been modelled as a single inverted pendulum (IP) to simulate the human quiet stance. Despite its popularity, the validity of the IP model has been challenged in many studies. Rather tha...
Main Authors: | , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Hindawi Limited
2021-01-01
|
Series: | Journal of Healthcare Engineering |
Online Access: | http://dx.doi.org/10.1155/2021/8884614 |
id |
doaj-8843b0220b394c02ae271de70f1edd5a |
---|---|
record_format |
Article |
spelling |
doaj-8843b0220b394c02ae271de70f1edd5a2021-06-21T02:25:22ZengHindawi LimitedJournal of Healthcare Engineering2040-23092021-01-01202110.1155/2021/8884614Characterizing the Validity of the Inverted Pendulum Model for Quiet StandingJia-Li Sung0Chih-Yuan Hong1Chin-Hsuan Liu2Posen Lee3Lan-Yuen Guo4Nan-Hung Lin5Chen-Wen Yen6Lih-Jiun Liaw7Department of Mechanical and Electro-Mechanical EngineeringDepartment of Mechanical and Electro-Mechanical EngineeringDepartment of Occupational TherapyDepartment of Occupational TherapyDepartment of Sports MedicineDepartment of Mechanical and Electro-Mechanical EngineeringDepartment of Mechanical and Electro-Mechanical EngineeringDepartment of Physical TherapyBy assuming that the human body rotates primarily around the ankle joint in the sagittal plane, the human body has been modelled as a single inverted pendulum (IP) to simulate the human quiet stance. Despite its popularity, the validity of the IP model has been challenged in many studies. Rather than testing the validity of the IP model as a true or false question, this work proposes a feature to quantify the degree of validity of the IP model. The development of the proposed feature is based on the fact that the IP model predicts that the horizontal acceleration of COM is proportional to the COP error which is defined as the difference between the center of pressure (COP) and the vertical projection of the center of mass (COM). Since the horizontal components of the acceleration of COM and the ground reaction force (GRF) are always proportional, the proposed feature is the correlation coefficient between the anterior-posterior (AP) components of GRF and the COP error. The efficacy of the proposed feature is demonstrated by comparing its differences for individuals in two age groups (18–24 and 65–73 years) in quiet standing. The experimental results show that the IP model is more suited for predicting the motion of the older group than the younger group. Our results also show that the proposed feature is more sensitive to aging effects than one of the most reliable and accurate COP-based postural stability features.http://dx.doi.org/10.1155/2021/8884614 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jia-Li Sung Chih-Yuan Hong Chin-Hsuan Liu Posen Lee Lan-Yuen Guo Nan-Hung Lin Chen-Wen Yen Lih-Jiun Liaw |
spellingShingle |
Jia-Li Sung Chih-Yuan Hong Chin-Hsuan Liu Posen Lee Lan-Yuen Guo Nan-Hung Lin Chen-Wen Yen Lih-Jiun Liaw Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing Journal of Healthcare Engineering |
author_facet |
Jia-Li Sung Chih-Yuan Hong Chin-Hsuan Liu Posen Lee Lan-Yuen Guo Nan-Hung Lin Chen-Wen Yen Lih-Jiun Liaw |
author_sort |
Jia-Li Sung |
title |
Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing |
title_short |
Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing |
title_full |
Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing |
title_fullStr |
Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing |
title_full_unstemmed |
Characterizing the Validity of the Inverted Pendulum Model for Quiet Standing |
title_sort |
characterizing the validity of the inverted pendulum model for quiet standing |
publisher |
Hindawi Limited |
series |
Journal of Healthcare Engineering |
issn |
2040-2309 |
publishDate |
2021-01-01 |
description |
By assuming that the human body rotates primarily around the ankle joint in the sagittal plane, the human body has been modelled as a single inverted pendulum (IP) to simulate the human quiet stance. Despite its popularity, the validity of the IP model has been challenged in many studies. Rather than testing the validity of the IP model as a true or false question, this work proposes a feature to quantify the degree of validity of the IP model. The development of the proposed feature is based on the fact that the IP model predicts that the horizontal acceleration of COM is proportional to the COP error which is defined as the difference between the center of pressure (COP) and the vertical projection of the center of mass (COM). Since the horizontal components of the acceleration of COM and the ground reaction force (GRF) are always proportional, the proposed feature is the correlation coefficient between the anterior-posterior (AP) components of GRF and the COP error. The efficacy of the proposed feature is demonstrated by comparing its differences for individuals in two age groups (18–24 and 65–73 years) in quiet standing. The experimental results show that the IP model is more suited for predicting the motion of the older group than the younger group. Our results also show that the proposed feature is more sensitive to aging effects than one of the most reliable and accurate COP-based postural stability features. |
url |
http://dx.doi.org/10.1155/2021/8884614 |
work_keys_str_mv |
AT jialisung characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT chihyuanhong characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT chinhsuanliu characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT posenlee characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT lanyuenguo characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT nanhunglin characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT chenwenyen characterizingthevalidityoftheinvertedpendulummodelforquietstanding AT lihjiunliaw characterizingthevalidityoftheinvertedpendulummodelforquietstanding |
_version_ |
1721369128000815104 |