Control of a 2-DOF powered ankle-foot mechanism

Evandro M. Ficanha, Mohammad Rastgaar, Kenton R. Kaufman

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper describes a finite state machine to control an ankle-foot prosthesis with two degrees of freedom (DOF) in the sagittal and frontal planes. Strain gauges were installed in the foot to provide ground reaction torques feedback for impedance and admittance controllers to be used at heel-strike and push-off of the gait, respectively. The quasi-static stiffness of the ankle with the active control was measured showing a near linear relationship between the torque feedback gain and the stiffness of the ankle. The performance of the finite state machine and controllers were also evaluated using a custom-made circular treadmill and the results were compared to the results of the prosthesis using position controller and inactive controllers. The results showed that the impedance/admittance controller was capable of tracking the desired input trajectory while decreasing the required torque at the ankle joint.

Original languageEnglish (US)
Title of host publication2015 IEEE International Conference on Robotics and Automation, ICRA 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9781479969234
StatePublished - Jun 29 2015
Event2015 IEEE International Conference on Robotics and Automation, ICRA 2015 - Seattle, United States
Duration: May 26 2015May 30 2015

Publication series

NameProceedings - IEEE International Conference on Robotics and Automation
ISSN (Print)1050-4729


Other2015 IEEE International Conference on Robotics and Automation, ICRA 2015
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Software
  • Artificial Intelligence
  • Electrical and Electronic Engineering
  • Control and Systems Engineering


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