mounts on the gearboxes.
The design of these mounts will
vary. If the builder is using the latter
method, then the design itself can
be as simple as a metal plate. This
piece would connect to both the
gearbox and the frame so that it can
be easily removed, but conversely
remain firmly attached. If the
builder uses the first method
mentioned, the design is slightly
more complicated. In this case, if
the builder requires the motors to
be encapsulated rather than just
dangling from the gearboxes, the
simple plate design will have to be
expanded based off the reason.
First, the builder may need to
protect the motors or the
surrounding components from
vibration or buckling. In this case,
the plate design would only need to
be modified by extending the piece,
such that it continues under the
motors. If the plate, however, is not
placed on the base of the gearbox
but on its face, then it would only
need to be modified with a second
larger piece on the base of the
gearbox. Or, use one piece with a
right angle bend in it. In both cases,
the extended plate under the motors
would provide more mounting holes
on the base of the frame, as well as
the base to mount pieces to both
absorb vibration from the motors
and protect them from buckling
out of place.
A second reason for a builder to
opt for a more complicated mount
might be for adding more armor
around the gearboxes and motors.
In this case, the plate design would
need to be modified by adding
separate plates or framing around
the motors and gearboxes in order
to mount the needed armor.
One last method I have seen
used in modular drive trains is what
is usually called drive pods. If you
have ever looked at combot kits,
you have probably seen them
before. The basic idea is to take the
motor and gearbox assembly and
then attach it to the driven wheel
and reduction area of the bot. As
one unit, you would only need two
of these assemblies and you would
have almost your entire drive system
done. Your chassis will get less complicated, as it will simply become a
box to hold everything else in.
Setting Up
The Electronics
As opposed to the drive system,
a modular electronics system is far
easier to set up in your bot. The first
thing to consider is exactly where
you will need to place the wiring,
and most of your work is finished.
Quick release connections are
important since you will want to be
able to take out and put back this
module quickly, without destroying
your wiring. The module itself is
meant to contain the electronic
components, such as your speed
controllers and the programming
board. A simple way to do this is to
mill out slots in material such as
UHMW that fit the dimensions of
those components and screw these
pieces directly into the material.
From there, make sure you have
milled out the proper channels for
the wiring you need and make the
material deep enough. Then, put
one cover over the entire module,
thereby covering your components,
and you are finished. If you are
already protecting the components
by your combat armor, it might be
nice to use clear Lexan as a cover in
order to be able to quickly see
inside without having to take off
the cover each time.
The Weapon System
A modular weapon system can
be easier or harder than the other
two assemblies, depending on the
type of bot you are building and
what kind of changes you want to
be able to make. Beginning with
the easier end of the spectrum,
thwack and wedge bots are the
simplest to modify. If you are staying
within these two confines, it’s simple
to modify a variety of wedge ramps
and thwack weapons to switch in
and out, depending on the
opponent. Also, if you are planning
to switch between those types, with
simple planning it should be easy
enough to turn your wedge into a
good thwack bot, and vice versa.
More difficulty comes when you
are working with spinner types,
such as shell and drum bots. It
wouldn’t be too hard to switch a
spinning blade for a spinning shell
as long as you design your chassis
accordingly, but to switch out a
spinning bar for something like a
drum would be difficult. That would
require not only having the proper
mounts in place ahead of time, but
weapon and motor assemblies that
can be pulled out and changed in
terms of orientation. One example I
have seen was a team switching
from a drum to a wedge after the
team’s drum was destroyed. That is
a good precaution, but one that
requires specific circumstances.
That’s A Wrap!
A modular combot has a lot of
benefits, but like all things, only if
done properly. I hope this article
helps you the next time you are
thinking about the versatility of
your robot. SV
EVENTS
Completed Event
Completed Event for
Aug 15 to Sep 15, 2009
Kilobots XV was presented by the
Saskatoon
Combat
Robotics Club
on September
4th and 5th
in Saskatoon,
Canada. SV
SERVO 11.2009 31