Artificial hand that mimics human hand movements

London: Engineers have developed an artificial hand that has sensory properties and can perform extremely precise movements. The research team led by Professor Stefan Seelecke from Saarland University is using a new technology based on the shape memory properties of nickel-titanium alloy. The new technology enables the fabrication of flexible and lightweight robot hands for industrial applications and novel prosthetic devices.

The muscle fibres are composed of bundles of ultrafine wires that are able to tense and flex. The engineers have provided the artificial hand with muscles that are made up from ultrafine nickel-titanium alloy wires whose diameter is similar to that of a human hair and that can contract and relax.

The term 'shape memory' refers to the fact that the wire is able to 'remember' its shape and to return to that original predetermined shape after it has been deformed. Multiple strands of shape-memory wire connect the finger joints and act as flexor muscles on the front-side of the finger and as extensor muscles on the rear. In order to facilitate rapid movements, the engineers copied the structure of natural human muscles by grouping the very fine wires into bundles to mimic muscle fibres. These bundles of wires are as fine as a thread of cotton, but have the tensile strength of a thick wire.