Design, development, and clinical validation of a two degrees of freedom compliant ankle-foot prosthesis based on a 4-4r parallel mechanism

Xiu, H; Han, Y; Wang, X; Zhang, Y; Liang, W; Wei, G; Ren, L; Ren, L

Abstract

Compared with active prostheses, passive compliant ankle prostheses offer the advantages of reduced energy consumption, a lighter weight, a simple structure, and lower costs. However, although various commercial products are available, these designs do not provide adequate degrees of freedom (DOFs) for movement. This paper presents a compliant passive ankle–foot prosthesis (CPAF) capable of 2-DOF rotation during locomotion. The CPAF uses a 2-DOF parallel mechanism to support the bodyweight and offer limited rotation during movement, and it incorporates a compliant component to facilitate and generate torque to conform to uneven terrains. The kinematics of the parallel mechanism, including the workspace and singularities, were investigated. Then, a prototype was developed, and the performance evaluations showed that sufficient torque could be generated with an appropriate range of motion for the ankle. Concequently, clinical validations were conducted: the dynamic analysis indicated that the CPAF provided good gait movement and generated sufficient ankle torque during level-ground walking, and the metabolic tests demonstrated that the configuration-4 of the compliant component could achieve the best efficiency during walking.

• Journal Article Type: Article
• Acceptance Date: Feb 28, 2022
• Online Publication Date: Mar 6, 2022
• Publication Date: Jun 1, 2022
• Deposit Date: Mar 29, 2022
• Publicly Available Date: May 6, 2022
• Journal: Mechanism and Machine Theory
• Print ISSN: 0094-114X
• Publisher: Elsevier
• Volume: 172
• Pages: 104818
• DOI: https://doi.org/10.1016/j.mechmachtheory.2022.104818
• Publisher URL: https://doi.org/10.1016/j.mechmachtheory.2022.104818
• Related Public URLs: http://www.journals.elsevier.com/mechanism-and-machine-theory/
• Additional Information: Funders : National Key R&D Program of China; Grant Number: 2018YFC2001301