Inverse Kinematics for Upper Limb Compound Movement Estimation in Exoskeleton-Assisted Rehabilitation

Table 1

Contributions of this paper with respect to closely related works.

Work	Method	Method inputs	Method evaluation	Metrics
[23]	EIKPE applied to single 1-DOF joint movements	(a) Exoskeleton and Human link lengths; (b) Exoskeleton joint angles	(1) Studied angles: elbow and wrist joint angles; (2) Reference angles: obtained from marker-based MOCAP; (3) Movements: single 1-DOF elbow and wrist joint movements (wearing the Exoskeleton)	RMSE of elbow and wrist angles
[21]	Estimation of the arm swivel angle such that the hand is efficiently retracted towards the head region	(a) Shoulder position; (b) Initial elbow position; (c) Wrist pose; (d) Point on the head region that minimizes the estimation errors	(1) Studied angles: arm swivel angle; (2) Reference angles: obtained from redundant marker-based MOCAP; (3) Movements: compound movements of (a) object reaching and (b) rotation of a doorknob (not wearing the Exoskeleton)	Mean absolute error of the arm swivel angle
This paper	EIKPE applied to compound movements (multi-DOF and multi-joint)	Same as [23]	(1) Studied angles: GH and elbow joint angles; (2) Reference angles: obtained from redundant marker-based MOCAP; (3) Movements: compound movement of object prehension (wearing the Exoskeleton)	(i) LFM, RMSE, and ROM error of the GH and elbow angle estimations provided by the Exoskeleton and EIKPE; (ii) Statistical significance test of the results of RMSE and ROM errors