Assessment of upper-limb task and joint-based exoskeletons for rehabilitation

Abstract

Exoskeletons and other robotics devices have been used as a common practice to assist and automate rehabilitation exercises. As new exoskeleton designs arise, so does the requirement to assess these devices to ensure efficiency, patient safety, and avoid further injury development. A common challenge in the exoskeleton development process is acquiring proper alignment and fitting of the robotic devices to the human body. This challenge is prevalent due to certain factors such as subject variability and the complexity of the human body and its range of motion. These challenges often dictate the exoskeleton design approaches. Some design approaches have a focus on simplifying and mimicking the human body and joints (joint-based), while others have a focus on generating a specific task without having to align the exoskeleton to the corresponding limb joints to perform a desired anatomical motion (task-based). In this study, both mechanisms are assessed and compared on their alignment and fitting through prototype testing and musculoskeletal modeling and simulation using OpenSim. The assessment will examine and quantify the muscle forces and tendon lengths of specific muscle groups of the users while wearing the exoskeletons and performing the desired rehabilitation tasks. These assessment methods will provide an insight on each mechanism’s alignment to the human body, guide other exoskeleton researchers and developers to the most efficient and safest exoskeleton design, and encourage further exoskeleton design evolvement.