The Electronics and Computer Science (ECS) Department of Southampton University in the UK has chosen South African-manufactured Vesconite Hilube for various parts of an innovative low-mass sensor-rich prosthetic hand.
Vesconite Hilube is a polymer which is used in the thumb of the hand and as the bearing material for the ends of the worm and wheel shafts at the base of the fingers.
According to Vesconite, the polymer’s lower density (compared to alloys) was an important influencing factor in the decision to use it in the Southampton-Remedi hand.
“A main constraint in the design of a hand for the replacement of a lost natural hand is that its mass should be kept as low as possible,” said Researcher at ECS, Dr Paul Chappell.
As a result, the Southampton-Remedi hand uses carbon fibre sheet and Vesconite Hilube, with metals only being used on the actuators of the electric drives.
According to Dr Chappell, Vesconite Hilube’s self-lubricating properties mean that the gearbox does not require additional bearings at the end of the shafts.
The Southampton-Remedi hand has four motors that move the fingers and two motors that allow for flexion (movement towards the palm) and extension (movement away from the palm) as well as rotation of the thumb.
The smart artificial hand is designed with motors and gears to mirror the flexibility of the human hand while allowing each finger to move independently. The hand can grip and grasp objects securely and, when electrical power is turned off from the batteries, a stable grip should be maintained using worm-wheel gearboxes.
In addition, the current generation of the hand also incorporates touch, position, slip, texture and temperature sensors.
Dr Chappell has spent several years developing the Southampton Remedi-Hand. Increasing the number of grasping patterns and improving the sensory feedback from an object in the hand became key objectives of his research.
Southampton University has been at the forefront of some significant work on artificial limbs, and is also well known for the Southampton Hand Assessment Procedure, which assesses hand function.