A force augmenting exoskeleton for the human hand designed for pinching and grasping.

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 fivedigit 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 six healthy individuals. Using the device for grasping efforts significantly decreased the muscle activity necessary to maintain a constant force $( \mathrm {p}<0.001)$; however, no significant benefit was identified during pinching efforts. In conclusion, a novel 5-digit exoskeleton was designed, and functional testing identified a significant benefit of using the device during grasping efforts.