Design optimization of an above-knee prosthesis based on the kinematics of gait

Pejhan, S ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1109/IEMBS.2008.4650154
  3. Publisher: 2008
  4. Abstract:
  5. A dynamic model of an above-knee prosthesis during the complete gait cycle was developed. The model was based on a two-dimensional multi-body mechanical system and included a hydraulic and an elastic controller for the knee and a kinematical driver controller for the prosthetic ankle. The equations of motion were driven using Lagrange method. Simulation of the foot contact was conducted using a two-point penetration contact model. The knee elastic and hydraulic controller units, the knee extension stop, and the kinematical driver controller of the ankle were represented by a spring and a dashpot, a nonlinear spring, and a torsional spring-damper within a standard prosthetic configuration. The hip trajectory and net joint moment were considered as the initial conditions of the coupled differential equations. Design optimization of the prosthesis, to achieve the closest knee flexion pattern to that of the normal gait, resulted in a good correlation; the average differences with normal data were 3.3 and 3.4 deg for prosthetic knee and ankle joints, respectively. A parametric study showed that both increase and decrease of the stiffness by 50% caused an earlier knee flexion in stance phase and a lower knee flexion in swing phase. The effect of hydraulic controller damping coefficient on the flexion pattern of the prosthetic knee and ankle was only significant in the swing phase of the gait cycle. © 2008 IEEE
  6. Keywords:
  7. Automobile drivers ; Controllers ; Damping ; Equations of motion ; Hydraulics ; Implants (surgical) ; Average differences ; Contact models ; Coupled differential equations ; Damping coefficients ; Dashpot ; Design optimizations ; Gait cycles ; Good correlations ; Initial conditions ; Joint moments ; Knee extensions ; Knee flexions ; Knee prosthesis ; Mechanical systems ; Multi bodies ; Nonlinear springs ; Stance phase ; Swing phase ; Torsional springs ; Joint prostheses ; Biomechanics ; Energy metabolism ; Limb prosthesis ; Locomotion ; Mechanical stress ; Physiology ; Prostheses and orthoses ; Amputation ; Ankle Joint ; Artificial Limbs ; Biomechanical Phenomena ; Prosthesis Design
  8. Source: 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08, Vancouver, BC, 20 August 2008 through 25 August 2008 ; 2008 , Pages 4274-4277 ; 9781424418152 (ISBN)
  9. URL: https://pubmed.ncbi.nlm.nih.gov/19163657