Modeling and Identification of the Human-Exoskeleton Interaction Dynamics for Upper Limb Rehabilitation

摘要

A number of machines have been developed for the upper limb rehabilitation to meet patients' needs for upper limb rehabilitation exercises. As active exercise has proven to be effective and necessary for neural rehabilitation and motor recovery, it is suggested to be implemented to the rehabilitation machines. Toward this goal, the human motion desire should have been recognized exactly first. Because the muscle strength of the patient's upper limb may not be able to supply the gravity of the arm and the rehabilitation machines, some torques coming from the rehabilitation machines will be needed to supply the exercise. This paper is focused on modeling and identifying the human-exoskeleton interaction (HEI) dynamics, so that the motion desire is able to be recognized exactly based on it. First, the human arm can be taken as two links with three degrees of freedom (two DOF in shoulder, one in elbow). By combining the dynamics model of the human arm and the exoskeleton, the HEI dynamic model was formed. Meanwhile, the joint angles and torques of human arm can be measured indirectly by using the position and torque sensors mounted on the joints of the exoskeleton. In this way, a 19-parameter HEI dynamic model has been established using the Lagrange method based on the pseudo inertia matrix. The model can be used to estimate the torques during rehabilitation exercises after identifying the underdetermining dynamic parameters. The motion desire can be recognized by comparing the measured joint torques to the estimated ones. Finally, the feasibility of the HEI dynamic model is validated by simulation experiments.