  Individuals with spinal cord injury (SCI) and stroke who is lack of
manipulation capability have a particular need for robotic hand exoskeletons.
Among assistive and rehabilitative medical exoskeletons, there exists a sharp
trade-off between device power on the one hand and ergonomics and portability
on other, devices that provide stronger grasping assistance do so at the cost
of patient comfort. This paper proposes using fin-ray inspired, cable-driven
finger orthoses to generate high fingertip forces without the painful
compressive and shear stresses commonly associated with conventional
cable-drive exoskeletons. With combination cable-driven transmission and
segmented-finger orthoses, the exoskeleton transmitted larger forces and
applied torques discretely to the fingers, leading to strong fingertip forces.
A prototype of the finger orthoses and associated cable transmission was
fabricated, and force transmission tests of the prototype in the finger flexion
mode demonstrated a 2:1 input-output ratio between cable tension and fingertip
force, with a maximum fingertip force of 22 N. Moreover, the proposed design
provides a comfortable experience for wearers thanks to its lightweight and
conformal properties to the hands.
