MECHANICAL STRUCTURE IMPROVEMENT OF AN UPPER LIMB REHABILITATION ROBOT: BASED ON AN EQUIVALENT KINEMATIC MODEL

摘要

Several rehabilitation robots for upper limbs have been introduced so far, and clinical effectiveness was reported in several studies for the aged people or patients with stroke. Upper limb motor deficits of the patients have to be identified during the motor training, which requires the flexibility of mechanical structure. However, the users have difficulties in driving the previous robotic arms precisely because of the previous mechanical structure, especially when they are required to track a circle. This article gives a kinematic analysis on the previous mechanical structure of the previous robot, which is a two bar-linkage, two degrees of freedom mechanism, then solves the force on the handle grip during user's operation based on an equivalent kinematic model. The key of the problem is that force directions exerted by the user are not in the correct directions to drive the robot. Therefore, a new mechanical design using parallel robotic arms is suggested. The improvement is justified by comparing results from tracking circles using different robots.