Build Your Own Combat Robot

270 Build Your Own Combat Robot
FIGURE 12-7
BrainStem bug, a
six-legged walking
robot that uses
three BrainStems
to interpret two
R/C input signals
to control
12 different servos.
(courtesy of
Acroname)
The Robo-Goose demonstrates an important concept in robotics control that
we will call microcontroller assisted control. The inputs coming from the operator
are translated into commands that affect certain motions on the robot. In mathematics,
this is called a mapping; and in the case of the goose, two inputs (steering
and forward motion) are translated, or mapped, into forward and reverse commands
for the right and left thruster motors on the goose.
The BrainStem Bug
The BrainStem bug also uses microcontroller-assisted control to manipulate many
different outputs from two simple inputs. The two outputs from the R/C receiver
are fed into a small parallel microcontroller core consisting of three networked
BrainStem controllers. Each BrainStem controls two legs, one for the front pair,
one for the middle, and one for the back pair of legs. Figure 12-7 shows a photograph
of the walking robot.
Simple forward and backward commands from the transmitter are translated into
complex walking patterns with six servo actuators controlling the left legs and six
more controlling the right legs of the robot. In this case, the assistance of the computer
becomes crucial to the operation of the robot. Twelve servo actuators control the
robot, and complex patterns are used to make the robot walk forward and backward,
turn right and left, and even spin right or left while stepping in place.