Design and Testing of a Galfenol Tactile Sensor Array

Abstract

The smart material Galfenol, Fe(100-x)Ga(x), where 15<x<28, offers a unique combination of mechanical and magnetostrictive properties that are expected to lead to its use in new sensor and actuator concepts. This thesis seeks to determine if Galfenol can be used to develop a 2-dimensional array of force sensors as part of a 3-D magnetic circuit that, if properly scaled, could mimic the tactile force sensing capabilities needed for use in robotic grippers, prosthetic devices, and robotic surgery. This concept takes advantage of the fact that Galfenol is not brittle and its permeability has high sensitivity to mechanical loads. The hypothesis is that applying stress or force to one or more of the Galfenol rods will produce changes in Galfenol's permeability which will produce changes in the flux density distribution in the magnetic circuit that can be used to determine information about both the load's magnitude and location. The studies performed demonstrated that the decrease in permeability of a loaded rod results in complex changes in magnetic flux. Results from this thesis include recommendations for modifications to better match the rod flux density to the applied load levels and prevent rod top separation.