Fully Wearable Actuated Soft Exoskeleton for Grasping Assistance in Everyday Activities

Abstract

Worldwide, over 50 million people suffer from persistent hand impairments after stroke or spinal cord injury (SCI). This results in major loss of independence and quality of life. Robotic hand exoskeletons can compensate for lost motor function and assist in grasping tasks performed in everyday activities. Several recent prototypes can partially provide this assistance. However, it remains challenging to integrate the dexterity required for daily tasks in a safe and user-friendly design that is acceptable for daily use in subjects with neuromotor hand impairments. We present the design of RELab tenoexo; a fully wearable assistive soft hand exoskeleton for daily activities. We present sleek mechanisms for a hand module that generates the four most frequently used grasp types, employing a remote actuation system that reduces weight on the hand. For optimal assistance and highest adaptability, we present various design and control options to customize the modular device, along with an automated tailoring algorithm that allows automatically generated hand modules for individual users. Mechanical evaluation shows that RELab tenoexo covers the range of motion and the fingertip forces required to assist users in up to 80% of all grasping activities. In user tests, we find that the low weight, unintrusive size, high wearing comfort, and appealing appearance are beneficial for user acceptance and usability in daily life. Finally, we demonstrate that RELab tenoexo leads to an immediate improvement of the functional grasping ability in a subject with SCI.