Design of Human–Machine Compatible Ankle Rehabilitation Robot Based on Equivalent Human Ankle Model

摘要

In this letter, a human–machine compatible ankle rehabilitation robot (HMCARR) is proposed to help stroke patients with motion dysfunction recover their motor function. The HMCARR can make the human ankle center-of-rotation (H-CoR) and the ankle rehabilitation robot center-of-rotation (R-CoR) coincide in real-time. The overall idea is to analyze from the “human” perspective to the “human–machine” perspective, and then to the “machine” perspective. Firstly, from the “human” perspective: a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">spherical-pair-with-clearance equivalent human ankle model</i> and a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H-CoR estimation model</i> are proposed, and the motion range of the H-CoR is analyzed. Secondly, from the “ human–machine” perspective: to obtain the mechanical design principles of the HMCARR, degree-of-freedom (DOF) and kinematic analyses of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">human–machine closed chain model</i> are conducted. Finally, from the “machine” perspective: DOF, kinematics, singularity, sensitivity, and workspace analysis are performed for the HMCARR based on a 3-RRCRR parallel mechanism, where R and C represent a revolute pair and a cylindrical pair, respectively. This study indicates that the mechanical design principles of the HMCARR include three requirements for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DOFs, kinematic independence, and position workspace.</i> The results suggest that the HMCARR based on the 3-RRCRR parallel mechanism can achieve coincidence between H-CoR and R-CoR in real-time.