The development of an artificial hand using nickel-titanium as actuators

Abstract

This thesis outlines a proposed mechanical design, prototyping and testing of a five fingered artificial hand made of 15 articulated joints actuated by Shape Memory Alloys (SMAs) mimicking muscular functions. SMAs Artificial muscles were incorporated in the forearm and artificial tendons made of nylon wires passing through a hollow palm transmit the pulling force to bend the fingers. Torsion springs set in each joint of the fingers create enough restoring force to straighten the finger when the actuators are disengaged. Nickel-Titanium (NiTi) wires were intrinsically embedded within the hand structure allowing significant movements mimicking human hand-like gestures. A control box made of switches connected to the artificial hand helps to control each gesture. A modular approach was taken in the design to facilitate the manufacture and assembly processes. Nickel-Titanium wires were used as actuators to perform the artificial muscle functions by changing their crystallographic structures due to Joule's heating. Rapid prototyping techniques were employed to manufacture the hand in ABS plastic.