used along with the target coordinates to calculate the
desired heading. As before, we can also get the distance to
target in this section. Next, we want to obtain the current
heading from the compass module and compare it to our
desired heading. Any course corrections are applied by the
motion routines which also handle ramping and speed
changes. The skid-steering design is quite nice for this type
of application, however, a tail-wheel robot with differential
drive would be just as effective. The ability to turn in place
has advantages in this type of application.
To really appreciate this project, you need to see it in
action. To that end, videos of this version of the GPS
Navigating robot will be available (see Resources sidebar).
As with many projects of this type, development will be
ongoing until I am happy with the performance of the
design given the available resources. Eventually, this robot
Savage Circuits You Tube Channel
FIGURE 3. Certain obstacles proved to be a challenge.
chassis will pave the way for a Stingray version of the code
which will, of course, run on a Propeller, but will also add
additional sensors including wheel encoders.
Having just obtained some Windows 7 compatible
flowchart software, I should have a flowchart for the code
up on the project page. The flowchart will be very detailed
about what the code is doing. It is my hope that this will
make it easier to port the routines over to your favorite
microcontroller. Remember, the code is heavily commented
to help, as well.
As I wrap up this article, I want to remind you about
my website. Besides hosting all my projects and videos, the
site is forum-based. If you prefer videos, most projects have
video tutorials. If you have any feedback, feel free to
contact me ( email@example.com). I hope you’ll be able
to apply all these directions to your projects. SV
STEER WINNING ROBOTS
Perform proportional speed, direction, and steering with only two Radio/Control channels for vehicles using two
separate brush-type electric motors mounted right and left
with our mixing RDFR dual speed control. Used in many
successful competitive robots. Single joystick operation: up
goes straight ahead, down is reverse. Pure right or left twirls
vehicle as motors turn opposite directions. In between stick
positions completely proportional. Plugs in like a servo to
your Futaba, JR, Hitec, or similar radio. Compatible with gyro
steering stabilization. Various volt and amp sizes available.
The RDFR47E 55V 75A per motor unit pictured above.
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