Development of an Assistive Robot for the Torque Analysis of Upper Extremity Joints

Main objective of this research is to find out the torque characteristics and its relation to critical parameters that are essential to run an exoskeleton. The torque required for the arm movements, joint torques because of gravity and residual forces are the key parameters that one need to consider while designing an exoskeleton for the upper extremity joints. For finding out these parameters, experiments were conducted to measure the forces in the forearm while moving the arm to the various position. These force values were converted to torques at the elbow and shoulder, and these values are presented in the paper. The existing exoskeletons were bulky and cumbersome which made them limited for this application. The complexity of the existing exoskeletons created the need for an economical, lightweight system which can provide more dexterity. Rehabilitation therapies do not require extremely complex exoskeleton designs. The proposed exoskeleton was built upon our research experience in wire driven manipulators in the rehabilitation robotics. This cable drive approach will reduce the overall weight of the exoskeleton and helps in a robust control of the arm movements. This paper describes the analysis the experimental data obtained from five subjects.