Title
Design and validation of a platform robot for determination of ankle impedance during ambulation.
Abstract
In order to provide natural, biomimetic control to recently developed powered ankle prostheses, we must characterize the impedance of the ankle during ambulation tasks. To this end, a platform robot was developed that can apply an angular perturbation to the ankle during ambulation and simultaneously acquire ground reaction force data. In this study, we detail the design of the platform robot and characterize the impedance of the ankle during quiet standing. Subjects were perturbed by a 3° dorsiflexive ramp perturbation with a length of 150 ms. The impedance was defined parametrically, using a second order model to map joint angle to the torque response. The torque was determined using the inverted pendulum assumption, and impedance was identified by the least squares best estimate, yielding an average damping coefficient of 0.03 ± 0.01 Nms/° and an average stiffness coefficient of 3.1 ± 1.2 Nm/°. The estimates obtained by the proposed platform robot compare favorably to those published in the literature. Future work will investigate the impedance of the ankle during ambulation for powered prosthesis controller development.
Year
DOI
Venue
2011
10.1109/IEMBS.2011.6092017
EMBC
Keywords
Field
DocType
medical robotics,torque,stiffness coefficient,electric impedance,3° dorsiflexive ramp perturbation,biomimetic control,nonlinear systems,ankle impedance,pendulums,least squares approximations,powered ankle prostheses,time 150 ms,least squares best estimate,angular perturbation,powered prosthesis controller,ambulation,damping,platform robot,damping coefficient,pendulum assumption,biomimetics,least square,biomechanics,robots,force,inverted pendulum,ground reaction force,impedance,second order
Control theory,Inverted pendulum,Torque,Simulation,Control theory,Computer science,Electrical impedance,Ground reaction force,Artificial intelligence,Pendulum,Robotics,Ankle
Conference
Volume
ISSN
ISBN
2011
1557-170X
978-1-4244-4122-8
Citations 
PageRank 
References 
1
0.66
1
Authors
4
Name
Order
Citations
PageRank
Elliott J. Rouse15412.27
Levi J Hargrove243842.47
Michael A. Peshkin3812104.61
Todd A Kuiken48515.61