Impact of Misalignment on Wearable Arm Robotic System

With the advancement of wearable robotic systems, several issues have been observed, and one significant concern is the misalignment between human joints and exoskeleton joints. The present study focuses on analyzing the impact of kinematic mismatch and misalignment in wearable robotic systems by considering contact and constraint reaction forces at joints, as well as the required moments to execute primary movements of the human arm. The primary focus is on the key activity of flexion/extension motion of the human arm and examines two configurations of an exoskeleton coupled with the human arm. In configuration 1, a 2-degree-of-freedom exoskeleton is used, with one degree of freedom at the shoulder joint and one at the elbow joint. These degrees of freedom are aligned to correspond with the shoulder and elbow joints of the human arm in the coupled model. In configuration 2, modifications have been made to the exoskeleton to account for the complexity of the human shoulder, which has five degrees of freedom. In this modified version, five revolute joints at the shoulder joint are included to mimic the shoulder’s five degrees of freedom. This modified exoskeleton is expected to be more compatible and accurately replicate the motion of the human arm.