Developing new frontiers in the Rubber Hand Illusion: Design of an open source robotic hand to better understand prosthetics

In psychology the Rubber Hand Illusion (RHI) is
an experiment where participants get the feeling that a fake
hand is becoming their own. Recently, new testing methods
using an action based paradigm have induced stronger RHI.
However, these experiments are facing limitations because they
are difficult to implement and lack of rigorous experimental
conditions. This paper proposes a low-cost open source robotic
hand which is easy to manufacture and removes these limitations.
This device reproduces fingers movement of the participants
in real time. A glove containing sensors is worn by the
participant and records fingers flexion. Then a microcontroller
drives hobby servo-motors on the robotic hand to reproduce
the corresponding fingers position. A connection between the
robotic device and a computer can be established, enabling the
experimenters to tune precisely the desired parameters using
Matlab. Since this is the first time a robotic hand is developed
for the RHI, a validation study has been conducted. This study
confirms previous results found in the literature. This study
also illustrates the fact that the robotic hand can be used to
conduct innovative experiments in the RHI field. Understanding
such RHI is important because it can provide guidelines for
prosthetic design.