Brain-Controlled Wheelchair Through Discrimination of Two Mental Tasks

Abstract

This paper presents a Brain-Computer Interface (BCI) system that enables people to drive a robotic wheelchair without performing any muscular movement, but solely based in the mental activity. Through specific mental tasks, subjects can control theirelectroencephalographic (EEG) signals, which are analyzed and processed by the BCI system in order to generate navigation commands. The control paradigm relies on only two mental tasks but it allows subjects to choose among four different commands; this way, the classification error is kept to its minimum, what makes the system safer. An experiment was carried out in which a subject participated in a training session, a virtual navigation task, and finally a navigation session with the real wheelchair.

Switch Mode to Control a Wheelchair Through EEG Signals

“…The subject initially participated in one initial training session for calibration purposes in which, immersed in a virtual environment (VE), he had to control the displacement of a car to the right through right hand motor imagery (MI) task, or to maintain the car in a straight line through a relaxed state [5], [6]. Signal processing consisted of extracting EEG parameters and classifying them according to the two mental tasks.…”

“…The navigation paradigm was identical to the one used in [5], [6]. In order to control the wheelchair, a graphical interface was presented to the users in order to offer them several navigation commands, which were selected through…”

“…Velasco-Álvarez, A. Fernández -Rodríguez and R. Ron-Angevin P the discrimination of only two mental states. The navigation consists of a circle divided into four parts, which correspond to the possible navigation commands (move forward, F, turn right, R, move back, B and turn left, L), with a bar placed in the centre of the circle that is continuously rotating clockwise (see [5] and [6] for more details). If the classifier determines that the mental task is right-hand MI, the bar extends; otherwise (relaxed state), the bar length remains at its minimum size.…”

“…In continuous mode, once the command is selected, the wheelchair moves in a continuous way (see [6]). In switch mode, once a command is selected, the movement starts.…”

“…This paradigm has been used successfully to control a wheelchair using discrete movements [5] however, other strategies should be considered as for example, providing continuous movements [6]. In the present study, a new strategy based on switch mode control which have already been tested in a virtual wheelchair [7] is presented.…”