Design and development of a 7 degree-of-freedom powered exoskeleton for the upper limb
An exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. With applications in rehabilitation medicine and virtual reality simulation, exoskeletons offer benefits for both disabled and healthy populations. A pilot database defining the kinematics and dynamics of the upper limb during daily living activities was among several factors guiding the development of an anthropomorphic, seven degree-of-freedom (DOF), powered arm exoskeleton. Additional design inputs include anatomical and physiological considerations, workspace analyses, and upper limb joint ranges of motion. Utilizing a seven DOF model of the human arm to calculate joint torques from measured arm kinematics, a pilot database defining typical ranges of motion and torque was compiled from 19 arm activities of daily living. A second ADL study including 6 subjects (N=6) and 24 daily actions confirmed prior result of the pilot study toward the definition of design requirements. Proximal placement of motors and distal placement of cable-pulley reductions were incorporated into the design, leading to low inertia, high-stiffness links, and back-drivable transmissions with zero backlash. The design enables full glenohumeral, elbow, and wrist joint functionality. Potential applications of the exoskeleton as a wearable robot include: (1) a therapeutic and diagnostics device for physiotherapy, (2) an assistive (orthotic) device for human power amplifications, (3) a haptic device in virtual reality simulation, and (4) a master device for teleoperation. Termed the CADEN-7 (Cable-Actuated Dexterous Exoskeleton for Neuro-rehabilitation), the exoskeleton arm offers remarkable opportunities as a versatile human-machine-interface and as a new generation of assistive technology.
- Mechanical engineering