Abstract:
Conventional wheelchairs are predominantly
manual or joystick-operated electric wheelchairs. However,
operating these wheelchairs can be difficult or impossible for
individuals with severe physical disabilities. Due to losing
control of their physical limbs, they depend on an attendant for
assistance. As a remedy, bio-signals may be used as a control
mechanism since they are readily available and can be acquired
from any body part. This research proposes to use EOG signals
to vail a control mechanism and test it in a virtual and actual
electric wheelchair. The main contribution of the study is an
investigation of the use of EOG to control an electric wheelchair
in a virtual environment to determine safe control parameters
for wheelchair use in complex environments. A customized data
acquisition circuit was developed to acquire single-channel EOG
signals using wet electrodes. The acquired signal was filtered
and processed using feature extraction and classification
techniques in MATLAB software. Two customized control
environments were developed in Unity 3D, one with equally
partitioned sections and the other with sections decreasing in
size as the robot wheelchair approaches the target. Twenty-two
test subjects (mean age 24.5, std 1.5) participated in the study,
controlling the robot wheelchair in real-time with non or least
instances of collision and oversteering. The system achieved an
accuracy of 96.5% with a response time of 0.7s, translating to an
ITR of 70.6 bits/min. Overall, the participants managed to
navigate the virtual environment with a completion time of
101.94s ± 19.71 and 109.07s ± 13.25 for the male and female
participants, respectively. In the scene with decreasing section
sizes, 72% and 54% instances of collision and oversteering were
reported, respectively, highlighting the need to consider the
complexity of the control environment and the sufficiency of the
participants' control skills to ensure safety in operations. The
results confirm the usefulness of EOG as a control interface,
with little or no need for recalibration. It provides a promising
avenue for individuals with severe physical disabilities to
operate wheelchairs independently in complex environments,
enhancing their quality of life.
