Design and compatibility analysis of self-adjusting wrist rehabilitation exoskeleton mechanism

WANG Chuan-wei，SHAN Quan，CHEN Yan，ZHANG Rong-chuang
(School of Control Engineering, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China)

Abstract: Aiming at the problem of mechanism configuration in the process of designing wrist rehabilitation exoskeleton mechanism, referring to the kinematic properties of the human wrist joint, the3RPPR self-adjusting wrist rehabilitation exoskeleton mechanism was selected by mechanical analysis and the advanced space mechanism theory was used to design the configuration of the rehabilitation exoskeleton mechanism. By introducing two passive moving pairs and one passive rotating pair at the human-machine contact surface, the mechanism can alleviate the constraint forces and torques which were generated along the axis of the human body and were irrelevant to the training during the rehabilitation exercise, thus the human-machine compatibility was achieved. Human-machine closed-chain kinematics was used to establish the constraint equation, and the position relationship between the human wrist and the passive joint movements of the mechanism was calculated and expressed by using MATLAB. The results indicate that the introduced two passive moving pairs and one passive rotating pair have larger motion amplitudes, effectively alleviate the forces and moments that are irrelevant to the training along the human axis in the humanmachine contact during wrist rehabilitation training, and the designed exoskeleton rehabilitation mechanism can meet the needs of human wrist joint rehabilitation.
Key words: wrist rehabilitation; exoskeleton mechanism; self-adjusting mode; constraint equation; mechanism configuration