Multibody System Dynamics

, Volume 28, Issue 1–2, pp 109–124 | Cite as

A simple approach to estimate muscle forces and orthosis actuation in powered assisted walking of spinal cord-injured subjects

  • J. AlonsoEmail author
  • F. Romero
  • R. Pàmies-Vilà
  • U. Lugrís
  • J. M. Font-Llagunes


Simulation of walking in individuals with incomplete spinal cord injuries (SCI) wearing an active orthosis is a challenging problem from both the analytical and the computational points of view, due to the redundant nature of the simultaneous actuation of the two systems. The objective of this work is to quantify the contributions of muscles and active orthosis to the net joint torques, so as to assist the design of active orthoses for SCI. The functional innervated muscles of SCI patients were modeled as Hill-type actuators, while the idle muscles were represented by elastic and dissipative elements. The orthosis was included as a set of external torques added to the ankles, knees, and hips to obtain net joint torque patterns similar to those of normal unassisted walking. The muscle-orthosis redundant actuator problem was solved through a physiological static optimization approach, for which several cost functions and various sets of innervated muscles were compared.


Spinal cord injuries Active orthoses Musculoskeletal modeling Optimization Inverse dynamics 



This work is supported by the Spanish Ministry of Science and Innovation under the project DPI2009-13438-C03. The support is gratefully acknowledged.


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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • J. Alonso
    • 1
    Email author
  • F. Romero
    • 1
  • R. Pàmies-Vilà
    • 2
  • U. Lugrís
    • 3
  • J. M. Font-Llagunes
    • 2
  1. 1.Universidad de ExtremaduraBadajozSpain
  2. 2.Universidad Politécnica de CataluñaBarcelonaSpain
  3. 3.Universidad de La CoruñaFerrolSpain

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