Citation

Thatte N, Geyer H. IEEE Trans. Biomed. Eng. 2015; 63(5): 904-913.

Copyright

(Copyright © 2015, Institute of Electrical and Electronic Engineers)

DOI

10.1109/TBME.2015.2472533

PMID

26315935

Abstract

OBJECTIVE: Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion.

METHODS: We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user.

RESULTS: In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and eectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls.

CONCLUSIONS: The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. SIGNIFICANCE: This work provides a potential avenue for future development of control policies that help improve amputee balance recovery.

Language: en