A Novel Inverse Kinematics Method for Upper-Limb Exoskeleton under Joint Coordination Constraints
Stefano Dalla Gasperina, Keya Ghonasgi, Ana C. de Oliveira, Marta Gandolla, Alessandra Pedrocchi, Ashish Deshpande
Abstract
In this study, we address the inverse kinematics problem for an upper-limb exoskeleton by presenting a novel method that guarantees the satisfaction of joint-space constraints, and solves closed-chain mechanisms in a serial robot configuration. Starting from the conventional differential kinematics method based on the inversion of the Jacobian matrix, we describe and test two improved algorithms based on the Projected-Gradient method, that take into account joint-space equality constraints. We use the Harmony exoskeleton as a platform to demonstrate the method. Specifically, we address the joint constraints that the robot maintains in order to match anatomical shoulder movement and the closed-chain mechanisms used for the robot's joint control. Results show good performances of the proposed algorithms, which are confirmed by the ability of the robot to follow the desired task-space trajectory while ensuring the fulfilment of joint-space constraints, with a maximum error of about 0.05 degrees.
BibTeX
@inproceedings{iros2020_anovelinversekin,
title = {A Novel Inverse Kinematics Method for Upper-Limb Exoskeleton under Joint Coordination Constraints},
author = {Stefano Dalla Gasperina and Keya Ghonasgi and Ana C. de Oliveira and Marta Gandolla and Alessandra Pedrocchi and Ashish Deshpande},
booktitle = {IROS 2020},
year = {2020}
}