SYSTEM
OVERVIEW
The
802.15.4 ZigBee wireless standard is a compelling
platform for implementing an elegant localization
method. In addition to being inexpensive and low
power, it allows for enough bandwidth for other
types of communication, such as commands and tasks
for robots within the network. We used a ZigBee
evaluation kit from Freescale Semiconductor to implement
a proof-of-concept network for a WowWee Robosapien
1.0, which is a humanoid robot. We implemented the
prototype using the kit’s three ZigBee nodes to
simultaneously localize the robot with signal strength
measurements while controlling it with a minimal
command set.
Our
localization and control system features a Freescale
MC13192 evaluation board with three accelerometers
(MMA6261Q for the x- and y-axes and MMA126OD for
the z-axis) mounted on the Robosapien robot (see
Photo 1). The system also includes an MC13192 SARD
board connected to a PC via an RS-232 serial connector
and another MC13192 evaluation board in the environment.
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(Click
here to enlarge)
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Photo
1—Check out the Robosapien 1.0. We attached
a Freescale ZigBee node to its back so we could
control it. |
Figure
1 shows the nodes
attached to the Robosapien. The communications
model we used is based on a broadcast model in which
the senders and receivers aren’t addressed specifically,
but the packets incorporate a basic header describing
the kind of data they contain.
