Stiffness evaluation of a novel ankle rehabilitation exoskeleton with a type-variable constraint

Wang，Tun1,2; Lin，Yen Hua2; Spyrakos-Papastavridis，Emmanouil2; Xie，Sheng Quan3; Dai，Jian S.1,2

2023

10.1016/j.mechmachtheory.2022.105071

MECHANISM AND MACHINE THEORY   Impact Factor & Quartile

0094-114X

This paper presents a novel ankle rehabilitation exoskeleton with two rotational degrees of freedom, which is suitable for dynamical rehabilitation for patients with neurological impairments. Its stiffness performance is assessed in consideration that the interaction between the footplate and the ground may deflect the mechanism away from the desired/predefined motion patterns. The novel design employs a universal-prismatic-universal (U-P-U) joint link, whose constraint type changes between a couple and a line vector during manipulation of the exoskeleton. To conduct a stiffness analysis of such a mechanism with a type-variable constraint – for the first time – a modified screw-based method (SBM) is proposed. Comparisons with the results obtained from finite element analysis verified that, the modified SBM provides reliable estimates of the exoskeleton's stiffness within the complete workspace (covering the constraint-type transition configurations). The stiffness of the exoskeleton is further evaluated by acquiring the minimum/maximum stiffness values, after computing the distribution of the most crucial linear and angular stiffness parameters within the workspace. Moreover, the influence of the architectural parameters on the stiffness properties is considered for further design optimization.

Ankle rehabilitation exoskeleton Stiffness analysis Transition configurations Type-variable constraint

English

First ; Corresponding

Engineering and Physical Sciences Research Council[EP/S019790/1];Science, Technology and Innovation Commission of Shenzhen Municipality[ZDSYS20200811143601004];

ENGINEERING

2-s2.0-85139265439

Scopus

1.Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems,Southern University of Science and Technology,Shenzhen,518055,China
2.Centre for Robotics Research,Faculty of Natural,Mathematical & Engineering Sciences,King's College London,London,WC2R 2LS,United Kingdom
3.School of Electrical and Electronic Engineering,University of Leeds,LS2 9JT,United Kingdom

Wang，Tun,Lin，Yen Hua,Spyrakos-Papastavridis，Emmanouil,et al. Stiffness evaluation of a novel ankle rehabilitation exoskeleton with a type-variable constraint[J]. MECHANISM AND MACHINE THEORY,2023,179.

Wang，Tun,Lin，Yen Hua,Spyrakos-Papastavridis，Emmanouil,Xie，Sheng Quan,&Dai，Jian S..(2023).Stiffness evaluation of a novel ankle rehabilitation exoskeleton with a type-variable constraint.MECHANISM AND MACHINE THEORY,179.

Wang，Tun,et al."Stiffness evaluation of a novel ankle rehabilitation exoskeleton with a type-variable constraint".MECHANISM AND MACHINE THEORY 179(2023).