Introduction
Project MERCURY is developing a low-cost body- machine and brain-computer interface (BMI-BCI) hybrid system capable of controlling a robotic arm with 6 degrees freedom of movement. We have already designed, built and tested the robotic arm and a body- machine interface (BMI), specifically an exoskeletal position sensing harness worn by a human operator. Current research and development focus is to integrate a dry electrode BCI headset into the system. Design priorities have included an intuitive and immersive user interface, fast and smooth movement, portability and cost minimization.
Materials and Methods
A robotic arm prototype capable of moving along 6 degrees of freedom has been developed and tested, along with an exoskeletal position sensing harness (BMI) used to intuitively control it.
Commercially available dry electrode BCI headsets have been evaluated, a particular headset model (EMOTIV) has been selected and is currently being integrated into the hybrid BCI-BMI system.
Results
The combined arm-harness system has been successfully tested and met its design targets for speed, smoothness of movement and immersive control. Initial tests verify that an operator using the system can perform pick and place tasks following a rather short learning curve lasting a few minutes. Further quantitative and qualitative evaluation experiments are planned for the integrated BCI-BMI hybrid setup.
Discussion
With respect to the BMI part of the system, the prototype MERCURY device has been demonstrated to fulfill its design criteria as far as dexterity, speed and reliability is concern. Qualitative experiments are being currently being designed in order to evaluate how immersive the users consider this form of control to be. With respect to the BCI part of the system, several commercially available dry electrode headsets were considered before focusing on the MindWave (Neurosky Inc, CA, USA) and EPOC (Emotiv Systems,
Australia) models. The latter was selected for integration into the MERCURY system based on the number of dry electrode channels, number of detectable mental states and superior sampling rate.
Conclusions
It is possible to design a portable robotic arm interface comparable in size, dexterity, speed and smoothness of movement to the human arm at relatively low cost (material cost <2000€). The combined system achieved its design goals for intuitive and immersive robotic control and is currently being further developed into a BCI-BMI hybrid system for comparative experiments. Future applications range from medical prosthetics to tele-surgery and real-time remote control of robots operating in dangerous and safety-critical environments.