Development of an upper limb exoskeleton for rehabilitation training in virtual environment

In recent years, a great many robot-assisted therapy systems have been developed and applied in neural rehabilitation. In this paper, we develop a wearable upper limb exoskeleton robot for the purpose of assisting the disable patients to execute effective rehabilitation. The proposed exoskeleton system consists of 7 degrees of freedom (DOFs) and is capable of providing naturalistic assistance of shoulder, elbow, forearm, and wrist. The major hardware of the robotic system is introduced. The Denavit-Hartenburg (D-H) approach and Monte Carlo method are utilized to establish the kinematic model and analyze the accessible workspace of exoskeleton. Besides, a salient feature of this work is the development of an admittance-based control strategy which can provide patient-active rehabilitation training in virtual environment. Two preliminary comparison experiments are implemented on a healthy subject wearing the exoskeleton. The experimental results verify the effectiveness of the developed robotic rehabilitation system and control strategy.