Biomedical Engineering Reference
In-Depth Information
9.5 Robotic Tiles
9.5.1 The CirculaFloor
The “CirculaFloor” project was launched to profit from approaches taken by both the
Torus Treadmill and GaitMaster devices [
14
]. Locomotion interfaces often require
bulky hardware, since they have to carry the user's whole body. The Torus Treadmill
is a typical example of large hardware. Also, the hardware is not easy to reconfigure
to improve its performance or to add new functions. Considering these issues, the
goals of the CirculaFloor project were:
(1) To develop compact hardware for the creation of an infinite surface for walking.
The major disadvantage of existing locomotion interfaces being their difficult
installation.
(2) To develop scalable hardware architecture for future improvement of the system.
In order to achieve these goals, a new configuration for a locomotion interface
using a set of omni-directional movable tiles, or robotic tiles, was proposed. Each
tile is equipped with a holonomic mechanism that achieves omni-directional motion.
An infinite surface is simulated by the circulation of the robot tiles (Fig.
9.13
).
The motion of the feet is measured with laser scanning sensors. The sensor is a
non-contact laser measurement system that scans its surroundings two-dimensionally
like laser radar. The sensor radially measures distance between the scanner and an
object that reflects the laser. This system requires no auxiliary passive components
such as reflectors or position markers, so that the walker never requires putting any
obstructive sensors or markers.
The robot tile moves opposite to the measured direction of the walker so that the
motion of the step is canceled. The position of the walker is fixed in the real world
by this computer-controlled motion of the robot tiles. The circulation of the robot
tiles has the ability to cancel the displacement of the walker in an arbitrary direction.
Thus, the walker can freely change direction while walking. This advantage is as
same as the Torus Treadmill.
The combination of robot tiles provides a sufficient area for walking, and thus
precision tracing of the foot position as is needed in the GaitMaster is not required. It
has the ability to create an uneven surface by mounting an up-and-down mechanism
on each tile. Figure
9.14
shows robot tiles with lifting actuators presenting virtual
staircases.
9.5.2 User Study of the Robot Tile Approach
The first prototype system of the CirculaFloor was demonstrated at SIGGRAPH
2004 venue (Los Angeles). The behavior of 325 participants was videotaped using a
