Force augmenting five-digit exoskeleton for the human hand

Abstract

Almost 1 million Americans suffer from debilitative disorders or injuries to the hand, which result in decreased grip strength and/or impaired ability to hold objects. The objective of this study was to design and test the functioning of a five-digit exoskeleton for the human hand that augments pinching and grasping efforts. The exoskeleton digits and the wrist and forearm structure was computer designed and 3-D printed using ABS plastic, while the housing for the control system, motors, and batteries was constructed from laser-cut acrylic. The user’s finger movement efforts were monitored with force sensing resistors (FSR) located within the fingertips of the exoskeleton. A microcomputer-based control system monitored the FSRs and commanded linear actuators that augmented the wearer’s force production. The exoskeleton device was tested on four healthy individuals. A second exoskeleton hand was developed for demonstration purposes, with a few designs being tested before the design was finalized, with rubber bands, springs, and an internal braided wire structure to extend the fingers. This exoskeleton does not require any human interaction to move the fingers and instead follows a pre-determined algorithm.