Constant and Variable Stiffness and Damping of the Leg Joints in Human HoppingSource: Journal of Biomechanical Engineering:;2003:;volume( 125 ):;issue: 004::page 507DOI: 10.1115/1.1590358Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: The present study deals with the stiffness and damping profiles of the leg joints during the ground-contact phase of hopping. A two-dimensional (sagittal plane) jumping model, consisting of four linked rigid segments and including the paired feet, shanks, thighs, and the head–arms–trunk segment, was developed. The segments were interconnected by damped torsional springs, representing the action of the muscles, tendons and ligaments across the joint and of the other joint tissues. A regressive function was used to express stiffness and damping, and included second-order dependence on angle and first-order dependence on angular velocity. By eliminating redundancies in the numerical solution using multicollinearity diagnostic algorithms, the model results revealed that the correct and sufficient nonlinearity for the joint stiffness is of the first order. Damping was found negligible. The stiffness profiles obtained were bell-shaped with a maximum near mid-stance and nonzero edge values. In predicting the joint moments, the obtained variable joint stiffnesses provided a closer agreement compared to a constant stiffness model. The maximal stiffness was found to be in linear correlation with the initial stiffness in each joint, providing support to the of muscles’ preactivation strategy during the flight phase of hopping. All stiffnesses increased with increasing hopping frequency. The model presented provides an effective tool for future designing of artificial legs and robots and for the development of more accurate control strategies.
keyword(s): Damping AND Stiffness ,
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contributor author | Svetlana Rapoport | |
contributor author | Eli Isakov | |
contributor author | Joseph Mizrahi | |
contributor author | Eitan Kimmel | |
contributor author | Oleg Verbitsky | |
date accessioned | 2017-05-09T00:09:30Z | |
date available | 2017-05-09T00:09:30Z | |
date copyright | August, 2003 | |
date issued | 2003 | |
identifier issn | 0148-0731 | |
identifier other | JBENDY-26331#507_1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl/handle/yetl/127970 | |
description abstract | The present study deals with the stiffness and damping profiles of the leg joints during the ground-contact phase of hopping. A two-dimensional (sagittal plane) jumping model, consisting of four linked rigid segments and including the paired feet, shanks, thighs, and the head–arms–trunk segment, was developed. The segments were interconnected by damped torsional springs, representing the action of the muscles, tendons and ligaments across the joint and of the other joint tissues. A regressive function was used to express stiffness and damping, and included second-order dependence on angle and first-order dependence on angular velocity. By eliminating redundancies in the numerical solution using multicollinearity diagnostic algorithms, the model results revealed that the correct and sufficient nonlinearity for the joint stiffness is of the first order. Damping was found negligible. The stiffness profiles obtained were bell-shaped with a maximum near mid-stance and nonzero edge values. In predicting the joint moments, the obtained variable joint stiffnesses provided a closer agreement compared to a constant stiffness model. The maximal stiffness was found to be in linear correlation with the initial stiffness in each joint, providing support to the of muscles’ preactivation strategy during the flight phase of hopping. All stiffnesses increased with increasing hopping frequency. The model presented provides an effective tool for future designing of artificial legs and robots and for the development of more accurate control strategies. | |
publisher | The American Society of Mechanical Engineers (ASME) | |
title | Constant and Variable Stiffness and Damping of the Leg Joints in Human Hopping | |
type | Journal Paper | |
journal volume | 125 | |
journal issue | 4 | |
journal title | Journal of Biomechanical Engineering | |
identifier doi | 10.1115/1.1590358 | |
journal fristpage | 507 | |
journal lastpage | 514 | |
identifier eissn | 1528-8951 | |
keywords | Damping AND Stiffness | |
tree | Journal of Biomechanical Engineering:;2003:;volume( 125 ):;issue: 004 | |
contenttype | Fulltext |