  In recent years, Virtual Reality (VR) Head-Mounted Displays (HMD) have been
used to provide an immersive, first-person view in real-time for the
remote-control of Unmanned Ground Vehicles (UGV). One critical issue is that it
is challenging to perceive the distance of obstacles surrounding the vehicle
from 2D views in the HMD, which deteriorates the control of UGV. Conventional
distance indicators used in HMD take up screen space which leads clutter on the
display and can further reduce situation awareness of the physical environment.
To address the issue, in this paper we propose off-screen in-device feedback
using vibro-tactile and/or light-visual cues to provide real-time distance
information for the remote control of UGV. Results from a study show a
significantly better performance with either feedback type, reduced workload
and improved usability in a driving task that requires continuous perception of
the distance between the UGV and its environmental objects or obstacles. Our
findings show a solid case for in-device vibro-tactile and/or light-visual
feedback to support remote operation of UGVs that highly relies on distance
perception of objects.
