Here are some of my original ideas before discussing
them with brothers, relations, and friends. I gave the subject a bit of
thought, and then put my thoughts down on paper, and below is the result.
Please be aware that none of these suggestions are necessarily right, or the best options available. They are merely my own personal opinions and could be completely wrong, but I had to start somewhere! Below is part of a letter I sent to one of my brothers who said he was interested in the project, but wasn't sure where to start.
I have been giving the "Robot Wars" idea a bit more thought, and have put some ideas down on paper here. If you don't want all the waffle, you can go straight to the Summary paragraph at the end. If you want some more detail then read it all!
Have a look and if you're interested, we can have further chats.
Having watched a number of robot war battles, there are several points
to consider when building a robot yourself. To my mind there are four
main areas that need to be considered, and within each of these, there
are a number of alternatives, each with their own pros and cons. The main
categories I think need to be carefully thought through are:
The shapes seem to fall into several classes, some of which give you
a tactical advantage, and others that leave you vulnerable to attack.
The shell material can also provide advantages or leave you vulnerable.
Some of the plastic (or polycarbonate) materials seem to get punctured
very easily. Thin aluminum (eg less that 3mm) just doesn't seem to withstand
axe attacks very well either. A better cover material would be stainless
steel sheet, 2mm thick should do it. I think a fairly rigid triangular
based framework underneath the shell is also a must. Even in the shell
gets punctured, keeping it away from the delicate components inside will
make it survive a bit longer.
A wedge seems to give you the advantage of being able to slip underneath
opponents and turn them over. It also makes it easier to build a powered
scoop to actively raise or turn over opponents. There is a possibility
that the driving wheels could protrude both out from the bottom and the
top of the robot, which would allow it to continue should it be turned
over itself. Failing that, a scoop can act as a self-righting mechanism
if it is designed well enough.
A fairly successful body shape has been the tank with caterpillar tracks.
They can run either way up (when they are not covered with a mudguards),
and if the tracks are of the right type, they can give good grip on the
floor. If the tracks aren't designed too well, they can be the Achilles
heel instead of a benefit because they have little grip on the floor,
or can loose the tracks of the runners.
For want of a better term, I have lumped all the rest together as "others".
Provided that the shape gives adequate protection of the vulnerable internal
components and will not leave the robot stranded if it gets turned over,
then any shape can be used.
There have been countless so called "weapons" used by robots
that only pay lip service to the task of causing real damage. There seems
little point in having a weapon unless it has weight as well as speed
with which to inflict damage. Hypnodisk was one of the few that had real
damage capability. It had such a colossal flywheel that span at such a
high speed, that the damage it caused was considerable. Having swinging
hammers on a rotating spindle seems to offer little benefit when it can
be stopped after the first impact with the opponent. You need a weapon
with high momentum and a short "bite", and one that doesn't
come to rest after the first blow. You don't want a large bite on a rotating
weapon because it's a bit like moving a lathe's cutting tool too quickly
into the workpiece. You need to do it a bit at a time to get the best
result. E.g Hypnodisk works well because of this.
There are several different weight categories in Robot Wars. The ones
you see on Television are the heavy weights. The program producers also
choose robots that look appealing to the eye, are more impressive, and
will therefore attract more viewers. There are also lightweights, which
look more like the traditional radio controlled car racers. I think it
will be more interesting and challenging to build a heavyweight robot,
and in fact it may be difficult for it not to be a heavyweight by the
time you have batteries, gas cylinders, electric motors etc.,under the
bonnet. Weight also allows you to be more aggressive and not be pushed
about too much.
There seems to be only two alternative for transmission types: electric
and internal combustion engine (IC). If you choose IC, you need to have
a gearbox, clutch, etc, which is more complicated, heavy, and required
more room. Also you need to consider the fuel situation if you get turned
over. Electric motors are cleaner, don't require a gearbox or a clutch,
but do require electric batteries, which are heavy.
The issues that immediately come to my mind are how to interface the radio receiver to the robot controls such as the motor control and weapon actuators.
My suggested alternative is to use a small microprocessor board that
connects directly to the receiver. These boards can be bought commercially
and have the added advantage of reducing the number of superfluous components.
Having given it a bit of thought, the processor board can take the place
of the servos in the above picture because it can perform the speed control
function of the motors itself. It can therefore remove the need to have
the joystick, as well as reducing the hardware needed in the associated
speed control circuit.
After carefully considering the various areas listed above, I think the
first draft Robot design should be as follows:
Components such as the motors can either be bought new (a bit
expensive especially if the robot gets obliterated in the first few
seconds) or from surplus stores or scrap yards. Could use motors from
wheel chairs, lawnmowers, forklift trucks, invalid carriages, washing
machines, etc. Car starter motors are NOT very suitable because they
are "series field" motors and are very difficult to speed
control. Other components can be obtained from various sources or
scrounged from friends.
Last updated 23rd Oct 2000