Powered ankle-foot prostheses: A survey on sensing systems and control strategies

Erik Chumacero-Polanco, James Yang

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

Abstract

People who have suffered a transtibial amputation show diminished ambulation and impaired quality of life. Powered ankle foot prostheses (AFP) are used to recover some mobility of transtibial amputees (TTAs). Powered AFP is an emerging technology that has great potential to improve the quality of life of TTAs with important avenues for research and development in different fields. This paper presents a survey on sensing systems and control strategies applied to powered AFPs. Sensing kinematic and kinetic information in powered AFPs is critical for control. Ankle angle position is commonly obtained via potentiometers and encoders directly installed on the joint, velocities can be estimated using numerical differentiators, and accelerations are normally obtained via inertial measurement units (IMUs). On the other hand, kinetic information is usually obtained via strain gauges and torque sensors. On the other hand, control strategies are classified as high- and low-level control. The high-level control sets the torque or position references based on pattern generators, user’s intent of motion recognition, or finite-state machine. The low-level control usually consists of linear controllers that drive the ankle’s joint position, velocity, or torque to follow an imposed reference signal. The most widely used control strategy is the one based on finite-state machines for the high-level control combined with a proportional-derivative torque control for low-level. Most designs have been experimentally assessed with acceptable results in terms of walking speed. However, some drawbacks related to powered AFP’s weight and autonomy remain to be overcome. Future research should be focused on reducing powered AFP size and weight, increasing energy efficiency, and improving both the high- and the low-level controllers in terms of efficiency and performance.

Original languageEnglish
Title of host publication43rd Mechanisms and Robotics Conference
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791859230
DOIs
StatePublished - 2019
EventASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2019 - Anaheim, United States
Duration: Aug 18 2019Aug 21 2019

Publication series

NameProceedings of the ASME Design Engineering Technical Conference
Volume5A-2019

Conference

ConferenceASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2019
CountryUnited States
CityAnaheim
Period08/18/1908/21/19

Keywords

  • Control strategies
  • Powered ankle foot prostheses
  • Sensing system
  • Transtibial amputee

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  • Cite this

    Chumacero-Polanco, E., & Yang, J. (2019). Powered ankle-foot prostheses: A survey on sensing systems and control strategies. In 43rd Mechanisms and Robotics Conference (Proceedings of the ASME Design Engineering Technical Conference; Vol. 5A-2019). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/DETC2019-97511