Design and Construction of an Artificial Finger based on SMA Actuators

Abstract

Shape Memory Alloy (SMA) wires are currently employed in robotics, as actuators of prosthetic limbs and medical equipment due to advantages such as reducing the size in the application, high power-to-weight ratio and elimination of complex transmission systems. In this paper, a new prosthetic finger is presented using SMA wire actuators. This robotic finger has been designed and modeled with three revolute joints and three SMA wires as the tendon in order to adduction each phalange of the finger and torsional springs to restore themto their original positions. The dynamic model of the finger has been simulated and validated in MATLAB/Simulation under different input voltages. By using this simulation, kinematic and kinetic of this finger have been analyzed. Also, by attention of the design goals, the mechanism of artificial finger is defined and has been developed in the Solid Works software. Based on simulation results, optimal choice of parameters and system features has been obtained and a prototype of finger has been built and tested.The results of practical experiments show that the designed artificial finger can achieve to the desired positions with high accuracy. Also, the results of practical tests confirm validity, high accuracy and authenticity of simulation model.