Paper Info
Title
Flexion-Extension Wrist Impedance Estimation Using a Novel Portable Wrist Exoskeleton: a Pilot Study
Abstract
Although the wrist plays a crucial role in performing interactive tasks, the wrist impedance has not been deeply studied so far. Moreover, all studies that aimed at estimating wrist impedance cannot be carried out in unstructured environments, thus limiting the gamut of possible research in this field. The major reasons underlying such limitations are the encumbrance and the non-portability of the robots used for this kind of applications. Within this work we presented the validation of a novel portable wrist exoskeleton to estimate the passive impedance of the wrist in Flexion-Extension (FE). To this aim, we enrolled 9 subjects whose wrist was passively moved around FE of ± 20deg by the device, characterized by 1 active degree of freedom. During the experimental sessions, we measured the joint torque and joint displacement, and we derived the angular velocities through numerical differentiation. Considering the wrist as a linear time-invariant second order mechanical system, we estimated impedance evaluating stiffness and damping coefficients, neglecting the contribution of the inertia due to the low speed of the movement applied by the robot. To this aim, we run a linear regression which allowed us to estimate stiffness and damping values. Passive stiffness estimated was equal to 1. $794\pm 0.514\mathrm{N}\mathrm{m}/\mathrm{r}\mathrm{a}\mathrm{d}$ for extension and $1.418\pm 0.445\mathrm{N}\mathrm{m}/\mathrm{r}\mathrm{a}\mathrm{d}$ for flexion, confirming also the wellknown difference between extension and flexion (p=0.027). Passive damping was found equal to $2.054\pm 1.202\mathrm{N}\mathrm{m}\mathrm{s}/\mathrm{r}\mathrm{a}\mathrm{d}$ for extension and 1. $403\pm 1.196\mathrm{N}\mathrm{m}\mathrm{s}/\mathrm{r}\mathrm{a}\mathrm{d}$ for flexion. These results are consistent with previous studies reported in literature, demonstrating the efficacy of our fully portable wearable wrist robot in estimating the wrist impedance around FE.
Year
DOI
Venue
2020
10.1109/BioRob49111.2020.9224335
2020 8th IEEE RAS/EMBS International Conference for Biomedical Robotics and Biomechatronics (BioRob)
DocType
ISSN
ISBN
Conference
2155-1782
978-1-7281-5907-2
Citations 
PageRank 
References 
0
0.34
0
Authors
3
Name
Order
Citations
PageRank
Luigi Raiano100.34
Giovanni Di Pino2257.95
Domenico Formica38826.60