EPFL
 Biomedical Imaging GroupSTI
EPFL
  Publications
English only   BIG > Publications > Control of Walking


 CONTENTS
 Home Page
 News & Events
 People
 Publications
 Tutorials and Reviews
 Research
 Demos
 Download Algorithms

 DOWNLOAD
 PDF
 Postscript
 All BibTeX References

Optimal Control of Walking with Functional Electrical Stimulation: A Computer Simulation Study

D. Popović, R.B. Stein, M.N. Oğuztöreli, M. Lebiedowska, S. Jonić

IEEE Transactions on Rehabilitation Engineering, vol. 7, no. 1, pp. 69-79, March 1999.



Bipedal locomotion was simulated to generate a pattern of activating muscles for walking using electrical stimulation in persons with spinal cord injury (SCI) or stroke. The simulation presented in this study starts from a model of the body determined with user-specific parameters, individualized with respect to the lengths, masses, inertia, muscle and joint properties. The trajectory used for simulation was recorded from an able-bodied subject while walking with ankle-foot orthoses. A discrete mathematical model and dynamic programming were used to determine the optimal control. A cost function was selected as the sum of the squares of the tracking errors from the desired trajectories, and the weighted sum of the squares of agonist and antagonist activations of the muscle groups acting around the hip and knee joints. The aim of the simulation was to study plausible trajectories keeping in mind the limitations imposed by the spinal cord injury or stroke (e.g., spasticity, decreased range of movements in some joints, limited strength of paralyzed, externally activated muscles). If the muscles were capable of generating the movements required and the trajectory was achieved, then the simulation provided two kinds of information: 1) timing of the onset and offset of muscle activations with respect to the various gait events and 2) patterns of activation with respect to the maximum activation. These results are important for synthesizing a rule-based controller.


@ARTICLE(http://bigwww.epfl.ch/publications/jonic9902.html,
AUTHOR="Popovi{\'{c}}, D. and Stein, R.B. and
        O{\u{g}}uzt{\"{o}}reli, M.N. and Lebiedowska, M. and Joni{\'{c}},
        S.",
TITLE="Optimal Control of Walking with Functional Electrical
        Stimulation: {A} Computer Simulation Study",
JOURNAL="{IEEE} Transactions on Rehabilitation Engineering",
YEAR="1999",
volume="7",
number="1",
pages="69--79",
month="March",
note="")

© 1999 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from IEEE.
This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.