An Optimized Capture Point Concept Considering the Ankle Stiffness

2021 ◽  
Author(s):  
J. Q. Zhang ◽  
M. Cong ◽  
D. Liu ◽  
Y. Du
Keyword(s):  
Ankle Stiffness ◽  
Capture Point

scholarly journals Reliability of Bi-Axial Ankle Stiffness Measurement in Older Adults

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1162
Author(s):  
Hogene Kim ◽  
Sangwoo Cho ◽  
Hwiyoung Lee
Keyword(s):  
Older Adults ◽  
Range Of Motion ◽  
Angular Displacement ◽  
Plantar Flexion ◽  
Significant Negative Correlation ◽  
Talocrural Joint ◽  
Ankle Foot Orthosis ◽  
Ankle Stiffness ◽  
Ankle Movement ◽  
Test Retest Reliability

This study involves measurements of bi-axial ankle stiffness in older adults, where the ankle joint is passively moved along the talocrural and subtalar joints using a custom ankle movement trainer. A total of 15 elderly individuals participated in test–retest reliability measurements of bi-axial ankle stiffness at exactly one-week intervals for validation of the angular displacement in the device. The ankle’s range of motion was also compared, along with its stiffness. The kinematic measurements significantly corresponded to results from a marker-based motion capture system (dorsi-/plantar flexion: r = 0.996; inversion/eversion: r = 0.985). Bi-axial ankle stiffness measurements showed significant intra-class correlations (ICCs) between the two visits for all ankle movements at slower (2.14°/s, ICC = 0.712) and faster (9.77°/s, ICC = 0.879) speeds. Stiffness measurements along the talocrural joint were thus shown to have significant negative correlation with active ankle range of motion (r = −0.631, p = 0.012). The ankle movement trainer, based on anatomical characteristics, was thus used to demonstrate valid and reliable bi-axial ankle stiffness measurements for movements along the talocrural and subtalar joint axes. Reliable measurements of ankle stiffness may help clinicians and researchers when designing and fabricating ankle-foot orthosis for people with upper-motor neuron disorders, such as stroke.

Frontal Plane Ankle Stiffness Increases with Weight-Bearing

2021 ◽  
pp. 110565
Author(s):  
Marie Matos ◽  
Eric J. Perreault ◽  
Daniel Ludvig
Keyword(s):  
Weight Bearing ◽  
Frontal Plane ◽  
Ankle Stiffness

Design, Development, and Control of a Fabric-Based Soft Ankle Module to Mimic Human Ankle Stiffness

2019 ◽  
Author(s):  
Sunny Amatya ◽  
Amir Salimi Lafmejani ◽  
Souvik Poddar ◽  
Saivimal Sridar ◽  
Thomas Sugar ◽  
...  
Keyword(s):  
Design Development ◽  
Ankle Stiffness ◽  
Human Ankle ◽  
And Control

scholarly journals Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

2011 ◽  
Vol 105 (5) ◽  
pp. 2132-2149 ◽  
Author(s):  
Anindo Roy ◽  
Hermano I. Krebs ◽  
Christopher T. Bever ◽  
Larry W. Forrester ◽  
Richard F. Macko ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Frontal Plane ◽  
Chronic Stroke ◽  
Healthy Adults ◽  
Stroke Survivors ◽  
Passive Stiffness ◽  
Mechanical Stiffness ◽  
Treatment Protocols ◽  
Ankle Stiffness ◽  
Hemiparetic Stroke

Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults.

Surface height effects on postural control: A hypothesis for a stiffness strategy for stance*

1999 ◽  
Vol 9 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Mark G. Carpenter ◽  
James S. Frank ◽  
Cathy P. Silcher
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
High Surface ◽  
Quiet Standing ◽  
Vestibular Input ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Balance Confidence ◽  
Eyes Closed ◽  
Ankle Stiffness

One possible factor influencing the control of upright stance is the perceived threat to one's personal safety, i.e. balance confidence. We explored this factor by examining the control of stationary stance when standing on an elevated platform under various conditions of reduced visual and vestibular inputs. Twenty-eight adults (14 male and 14 female, mean age = 23.5 years) participated in the experiment. Postural control was examined by recording the amplitude variability (RMS) and mean power frequency (MPF) of center of pressure excursions (COP) over a 2-minute interval while participants stood in a normal stance on a low (0.19 m) and a high (0.81 m) platform with toes positioned either at or away from the edge of the platform. Vision was manipulated through eyes open and eyes closed trials. Vestibular input was reduced by tilting the head into extension [1]. Anterior-posterior RMS and MPF of COP were significantly influenced by an interaction between surface height and vision. When vision was available, a significant decrease in RMS was observed during quiet standing on a high surface compared to a low surface independent of step restriction. When vision was available MPF increased when subjects were raised from a low to a high surface. The mean position of the COP was significantly influenced by an interaction between height and step restriction. Differences in RMS and MPF responses to height manipulation were observed between genders in eyes closed conditions. Vestibular input influenced postural control at both low and high levels with significant increases in RMS when vestibular input was reduced. The reciprocal changes observed in RMS and MPF suggest modifications to postural control through changes in ankle stiffness. Vision appears to play a role in increasing ankle stiffness when balance confidence is compromised.

scholarly journals Push Recovery of a Position-Controlled Humanoid Robot Based on Capture Point Feedback Control

2017 ◽  
Author(s):  
Milad Shafiee-Ashtiani ◽  
Aghil Yousefi-Koma ◽  
Reihaneh Mirjalili ◽  
Hessam Maleki ◽  
Mojtaba Karimi
Keyword(s):  
Feedback Control ◽  
Humanoid Robot ◽  
Push Recovery ◽  
Capture Point

Support vector machine identification of a parallel cascade model of human ankle stiffness

2016 ◽  
Vol 10 ◽  
pp. 1359-1371
Author(s):  
Mujahed Aldhaifallah ◽  
David T. Westwick ◽  
K. S. Nisar
Keyword(s):  
Support Vector Machine ◽  
Cascade Model ◽  
Support Vector ◽  
Ankle Stiffness ◽  
Human Ankle

Relation of Maximal Ankle Dorsiflexion Angle and Passive Resistive Torque to Passive-Elastic Stiffness of Ankle Dorsiflexion Stretch

2002 ◽  
Vol 95 (1) ◽  
pp. 323-325 ◽  
Author(s):  
Richard L. Gajdosik ◽  
Ann K. Williams
Keyword(s):  
Multiple Regression ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Elastic Stiffness ◽  
Ankle Dorsiflexion ◽  
Regression Analyses ◽  
Moderate Correlation ◽  
Ankle Stiffness ◽  
Resistive Torque ◽  
Clinical Measurements

The maximal passive ankle dorsiflexion angle and the maximal passive resistive torque at this angle were measured for 81 women 20 to 84 years of age and correlated with the passive-elastic stiffness (stiffness) of an ankle dorsiflexion stretch. Pearson correlation coefficients and multiple regression analyses were used to examine whether the two clinical measurements could predict ankle stiffness. The maximal passive resistive torque showed a moderate correlation with stiffness in the full stretch range ( r = .69) and high correlation with stiffness in the last half of the full stretch range ( r = .84). The maximal dorsiflexion angle showed a low correlation with stiffness in the full stretch range ( r = .27) and in the last half of the full stretch range ( r = .36). The maximal passive resistive torque and the dorsiflexion angle together accounted for 54% of the stiffness variance in the full stretch range and 76% of the stiffness variance in the last half of the full stretch range. Thus, the clinical measurements of the maximal passive dorsiflexion angle and the maximal passive resistive torque were directly and significantly related to the ankle dorsiflexion passive-elastic stiffness and good predictors of stiffness in the last half of the passive ankle dorsiflexion stretch.

scholarly journals Stabilization of the Capture Point Dynamics for Bipedal Walking based on Model Predictive Control

2012 ◽  
Vol 45 (22) ◽  
pp. 165-171 ◽  
Author(s):  
Manuel Krause ◽  
Johannes Englsberger ◽  
Pierre-Brice Wieber ◽  
Christian Ott
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Bipedal Walking ◽  
Capture Point

scholarly journals Extraction of Guardrails from MMS Data Using Convolutional Neural Network

2021 ◽  
Vol 15 (3) ◽  
pp. 258-267
Author(s):  
Hiroki Matsumoto ◽  
◽  
Yuma Mori ◽  
Hiroshi Masuda
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Asset Management ◽  
Extraction Method ◽  
Point Clouds ◽  
Mobile Mapping ◽  
Method Point ◽  
Mobile Mapping Systems ◽  
Capture Point ◽  
Mapping Systems

Mobile mapping systems can capture point clouds and digital images of roadside objects. Such data are useful for maintenance, asset management, and 3D map creation. In this paper, we discuss methods for extracting guardrails that separate roadways and walkways. Since there are various shape patterns for guardrails in Japan, flexible methods are required for extracting them. We propose a new extraction method based on point processing and a convolutional neural network (CNN). In our method, point clouds and images are segmented into small fragments, and their features are extracted using CNNs for images and point clouds. Then, features from images and point clouds are combined and investigated using whether they are guardrails or not. Based on our experiments, our method could extract guardrails from point clouds with a high success rate.

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