Digital Signal Processing Reference
In-Depth Information
Figure 13.27
ActiveMedia's Amigobot robot base controlled by an FPGA with a Nios Processor
Some commercial robot bases are also available such as the Amigobot as seen
in Figure 13.27, the ER1 from Evolution Robotics and the mobile robot
platform from Drrobot. The Amigobot uses an RS-232C serial interface and the
ER1 uses USB for motor control. A robot base contains a motor, drive
electronics, sensors, and a battery, but it has no high-level controller.
One of the newest and most attractive low-cost options for a robot base is
iRobot's iCreate robot base as seen in Figure 13.28 (
www.irobot.com
). It is
basically a “Roomba” robotic vacuum cleaner without the vacuum parts. It
contains an internal microcontroller, two drive motors with feedback, audio
output, and several simple sensors (i.e., IR, bump or contact switches, and IR
cliff or surface drop-off sensors). Using an RS-232 serial port, motor
commands can be sent to the microcontroller and the sensor status can be read
back. An FPGA board running a Nios processor can talk to the iCreate
microcontroller using the RS-232 serial port. You can write the required robot
application code for the Nios processor in C.
6-32 screw holes are provided on top of the base that can easily be used to
mount an FPGA board using an additional flat rectangular piece of Plexiglas or
Lexan. The rectangular sheet of plastic bolts to the base using the four screw
holes above the open cargo area, and the FPGA board bolts to the sheet of
plastic. Power can be provided at up to 1 amp using the iCreate's internal
battery or there is also space in the cargo area for an additional battery pack for
the FPGA board. The internal battery voltage is 18V, so a 7, 9, or 5 volt DC
regulator (depends on which FPGA board) is needed to drop the voltage for the
FPGA board (note: too high of a DC input voltage will overheat the FPGA
board's internal DC regulator). A DB-25 connector seen at the center in Figure
13.28 provides all of the power and serial port connections needed.
