Biomedical Engineering Reference
In-Depth Information
As a result, most subjects marked under 10 % movements. It is assumed that 78 %
of the subjects on the CirculaFloor can walk stably.
On the contrary, the remaining 22 % of the subjects could not walk stably. The
reasons of unstable walk were categorized into following 5 classes: (1) tile was
moving when landing forefoot; (2) gait style was suddenly changed. E.g. a change
from wide based gait to narrow based gait was observed; (3) the subjects kicked
back tiles by their hind leg; (4) the subjects strolled along the edge of tiles; (5) The
subjects walked in an otherwise awkward fashion. These factors depended primarily
on the gait style of the subjects. The movable tiles were controlled to maintain a
desired velocity trajectory. However, when a subject applied a force to the tile that
was too large, the tile could move in an unexpected direction. Improvements to the
stability of the tile system are still required. Also, the subjects' shoes affecting their
gait pattern. It is difficult for subjects who wear high-heel to walk stably on the
device. The height of the movable tiles is 90 mm. Such subjects were fearful of even
small displacements of the tile.
A major limitation of the robot-tile-based locomotion interface seems however to
be its low walking speed. Very high circulation speed is required to follow natural
walking speed. The maximum running speed of the robot tile is limited due to the
upper limit of traction force of the holonomic mechanism (Fig.
9.15
).
Still, the circulating tiles seem to remain a very attractive and popular interactive
device. A more recent version of the robotic tiles was demonstrated at Tokyo Fiber
'09 art exhibition (Triennale, Milan). This updated version encloses new conductive
fibers mounted on each tile, making it possible to finely detect positions of the feet.
It was, observed to be a successful demonstration.
Fig. 9.15
Robot tiles exhibited at Tokyo Fiber 20009 (Photo:)
