This is only a preview of the September 2003 issue of Silicon Chip. You can view 24 of the 96 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Portable PIC Programmer":
Items relevant to "Current Clamp Meter Adaptor For DMMs":
Articles in this series:
Items relevant to "Digital Instrument Display For Cars, Pt.2":
Articles in this series:
Purchase a printed copy of this issue for $10.00. |
Robot
Wars
Competition, sport, combat, you name it, humans are a
competitive species. There is nothing like the roar of a crowd
as their team “slaughters” the opposition on the field. Whether
it is the dignified(?) chasing of balls about a golf course or the
intensely physical free-for-all we call football, we love to
watch a good contest (even if it is only on TV!).
O
f course for most of us, that’s
all we do. Watch. Actually getting out there and competing
in aggressive physical sports requires
a lot of training and exercise that we
intellectual technical types are usually
allergic to – until now.
There’s a new contact sport out
there and you can be the champion
of it without straining any more mus
cles than you need to win on your
PlayStation.
It’s called “Robot Wars”, “Bat
tleBots” or just plain CombatRobots.
It’s the sport for those who like to
battle with brains rather than brawn
8 S
hip
8
Silicon
iliconCC
hip
but still want the adrenalin rush that
comes from savagely rending your
opponent limb from limb, without
risking so much as a personal scratch
in the process.
Robot Wars is the ultimate “boys
toys” sport, at the same time as being
one of the most intense engineering
challenges and learning experiences
you can find. In principle, it’s simple.
It’s Robotic Darwinism or Survival
of the Fittest. You create (cue Thunder-roll and Mad Scientist Laughter)
a heavily armed and armoured re
mote-controlled destruction machine
and unleash it upon your opponent in
an arena where two robots enter and
one robot and a pile of scrap is left at
the finish.
Of course, that’s exactly what your
opponents have in mind for your ma
chine as well – so your mechanical
monster had better be tougher than
theirs or it will be going home in a
robotic body-bag.
Some drivers have compared the
adrenalin rush that comes while com
peting in these events to sky-diving or
professional drag racing. Others love
the intellectual challenge of building
a machine and putting it on the line
in a life-or-death match.
And all competitors agree that
the planning, design engineering,
www.siliconchip.com.au
www.siliconchip.com.au
The Tech sport of the new millennium
By Brett Paulin
He’s called “The Judge” –
but he’s also the jury and
executioner! In combat, all
of the exposed mechanics
and electronics is well
hidden and well protected.
materials science, machining skills,
electronics, strategy and just straight
cunning is the most enjoyable and
creative learning experience they
know of.
How did it start?
Back in 1992, a US engineer tried
to radio-control his vacuum cleaner
to make house-work more interesting.
After viewing the resultant destruc
tion wreaked in his living room, he
decided that it was so much fun, that
he would organise a competition for
people to pit their radio-control cre
ations against each other.
Several years down the track, there
www.siliconchip.com.au
are now two major TV shows, thou
sands of competitors, a wealth of
websites, PlayStation and PC Video
Games, remote control toys, Internet
Chat Forums, and even McDonald’s
happy-meal plastic toys of the most
Famous BattleBots in America.
The sport is continuing to grow
and diversify as people push the
boundaries of what can be done with
machines to destroy other machines.
Watching machines beat the bolts
out of each other is a hit. It has Quality
Violent Destruction and no one gets
hurt, physically, that is. Economic?
That’s another matter!
Australia is just starting to catch
up with the rest of the world in this
new sport, with new teams in every
state forming and building their first
robots, and starting to organise local
events with a view to holding a na
tional event soon.
The Channel 10 network has been
screening the UK “Robot Wars” series
while waiting for the sport to grow
locally. Welders are arcing and sol
dering irons are smoking as the first
generation of uniquely Australian
robots come to life.
Are they really robots?
Are they really robots? A common
question, given that most people think
September 2003 9
. . . into the valley of death, they rode . . . These hydraulically-operated crusher jaws can (and do!) operate with a force
measured in tonnes and are designed to disable an opponent robot by literally crushing it to death.
of C-3PO or Terminator when imagining a robot and something that looks
like a remote-controlled ditch-digger
doesn’t quite qualify.
Well, being remote-controlled (by
a human!) they are not autonomous,
so full-on robots like C-3PO might be
affronted but if C-3PO wants to argue
about it, then he had better bring along
a light-sabre to do so, because these
robots are NOT the sort to politely
disagree.
There are “Autonomous” (self-directed) classes but that’s a subject
for another article. For the moment,
remote-controlled machines
are where the real excitement
is, since they have a cunning
human brain behind the steel
muscles and the action is a lot
more “personal” in nature.
are the norm – things that smash, cut,
rip, flip, puncture and crush. Saws,
hammers, spikes, flippers, wedges,
drills, flywheels, clubs, pick-axes (no,
not the chip) and any other destructive
or fiendish implements you can devise
are permitted.
Prohibited weapons include explosives, electrical discharges or radio
jamming, chemical/corrosive substances, nets, fire (in most cases) and
radiation of any sort (lasers, masers,
gamma beams etc).
Why? Safety is the first reason –
your rocket launcher or napalm-gun
Rules
Rules? Well, yes, there ARE
some or it wouldn’t be long before
someone equipped their robot with
hand grenades or a Tesla coil and
vaporised everything within sight.
This is supposed to be a FUN sport
and having to compete and watch
from a concrete bunker in the desert
via TV wouldn’t quite be the same.
Basically, “Kinetic Energy” weapons
10 Silicon Chip
“Maximus”
is a classic
flipper-type robot,
intended to disable the
opposition by turning it upside-down.
may sound like a cool idea, until it
misses its target and hits something
else. Hopefully, whatever else it is
will be strong enough to stop it before
it then hits a spectator, so long-range
weapons are out. All projectiles must
be tethered to the robot.
Second, entertainment is the name
of the game. Watching one machine
rip chunks of steel off another with
a saw is much more fun than a light
tap with an electrode bearing 100kV
which instantly fries the electronics
and leaves a visually undamaged robot sitting still like a stunned mullet.
Likewise radio jamming is banned as
there is little point in having robot
machines helplessly twitching,
with the fighting going on in a
realm that can only be seen on
a spectrum analyser. Most of
the prohibited weapon rules
are either for your protection
or your entertainment.
You will be amazed at the
wide variety of machines possible within the scope of these
rules. Every competition reveals
a new idea that has competitors
re-designing and re-engineering
their machines to meet the opposition’s latest threat.
The rules vary slightly from compewww.siliconchip.com.au
The “pits” at a typical Robot battleground. You’ll find every possible configuration of robot, in all weight categories, with
every conceivable (and probably some inconceivable!) weaponry and defence mechanisms.
tition to competition, since some allow
flame throwers and some don’t; some
allow internal combustion engines
(ICE) to power spinning blades, etc and
others are worried about the fire hazard
they present. Some events are limited
by the strength of their arena walls, so
have a maximum weight class they can
handle. At one event in America recently, a super-heavyweight Hi-Speed
(150kg) Rammer Robot missed its target
and smashed clean through a foot-thick
brick wall into the car park!
A basic rule set that most events
build on can be found at the American
Robot Fighting League (RFL) website
at www.botleague.com
Types of robot
So, you have
an unbeatable
design in mind?
Most effective robot designs fall into a few major categories, each with their
own strengths and weaknesses – although sometimes a
new design will appear that
defies description, so this is only a
rough guideline. Feel free to innovate
and come up with something that does
not fit into any of these pigeonholes
to surprise your opponent. Just make
www.siliconchip.com.au
sure your “secret weapons” will pass
the safety rules.
Wedges – the simplest type of robot,
basically a mobile door-stopper, low
to the ground to get under the other
robot, scoop them and push them
around the arena – hopefully flipping
them over. Often sneered at since they
don’t have an active weapon, they are
still popular since they are the easiest
to build.
Lifters – like a wedge, with the addition of a moveable arm that makes it
easier to either flip the other robot over
or lift them and pin them against the
wall. These are very effective against
robots that cannot self-right or drive
inverted but ineffective if their oppo-
“Bone Saw”
– aptly named,
because it could!
nent has either ability.
Flippers – high-powered lifters,
usually driven by compressed gas
pneumatic rams, often capable of
tossing other robots high into the air
and causing massive damage when
they crash back to the ground. These
can be very dangerous and tricky to
build unless you have experience with
high-pressure gas.
Rammers – powerful, fast bulldozers are designed to shove the opponent
around the arena, into the walls and
physically slam into them at high
speed to cause damage; often fitted
with spikes and wedges to penetrate
the opponent upon impact.
Spinners – the masters of destruction, fitted with high-speed spinning
flywheels with cutting or bludgeoning
teeth on them. They cause massive
damage and sometimes rip pieces off the other robot
and send them flying. The bad news is
that they often break
themselves as well,
since the law of action and reaction means they absorb the same
impact energy back into their own
frames. There are limits on where they
can compete though, since bulletproof
arenas are required to protect the specSeptember 2003 11
tators from flying fragments.
Hammer-Bots – swinging sledge
hammers and pick axes. These are
impressive but difficult to build, since
accelerating heavy hammers quickly
and repeatedly requires ingenious mechanics and powerful motors. Often,
they are powered by pneumatic rams
like flippers – a very effective design
when done well, since many robots
have weak overhead armour and
sometimes the hammer can be used
as a self-righting mechanism as well.
Crushers – Hydraulic-powered
presses, sometimes with penetrating
spikes to concentrate the forces into
a small irresistible point. Not a very
popular design, since their jaws move
very slowly and it’s easy for an opponent to escape. They also require
careful engineering of their frame to
withstand the enormous forces they
have to exert without bending.
Circular Saws – visually exciting,
often sending off showers of sparks,
they usually also require a way of
temporarily immobilising the
opponent, since it’s hard to
saw something that won’t sit
still. Clamping jaws of some
sort make them a lot more
effective.
Thwack Bots – an unusual type of spinner, the
whole body of the robot is
spun around by driving its two
wheels in opposite directions,
with a hammer or spike on an
extended arm. The principle is that
all of the robot’s spinning mass goes
into the impact. The drawback is they
can’t move around while spinning, so
the opponent often just sits back and
waits for them to stop spinning before
attacking.
Weight classes
The biggest rule is WEIGHT. Obviously, there have to be limits here or
someone would fit a remote control to
an M1 Abrams Tank and laugh while
picking bits of the opposing robot out
of their treads after the match.
To keep things (relatively) sane, all
robots have to fit into a weight class,
and are only expected to battle other
robots of the same class. Your robot can
weigh anything up to the maximum
weight for a particular class. If you
go over it, you are up into the next
class and will be battling much fiercer
machines, so keeping an eye on your
machine’s weight is most important.
12 Silicon Chip
The accepted weight classes are:
Ant-weight: ................. 0.5kg
Beetle-weight:................. 1kg
Hobby-weight:................ 6kg
Feather-weight:............. 12kg
Light-weight:................. 25kg
Middle-weight:............. 50kg
Heavy-weight:............. 100kg
Super-Heavyweight:... 150kg
Naturally, the heavy and super-heavy classes are what most people dream of building, since they are
the most destructive and spectacular.
They are usually the ones that get the
most TV coverage.
However, they are also the most
expensive by far. Motors, batteries
and electronics that can muscle
150kg of steel about at high speed
are not cheap, and you will probably
have to settle for something lighter to
start with. The Feather-weight class
(12kg) is looking to be a very popular
class to start off in within Australia,
Is that really
a lawnmower blade up front?
Sure is – but don’t try mowing
your lawn with this one!
with the robots still big enough to
be impressive but small enough to
be manageable without a crane and
a trailer. When was the last time
you tried to move a 150kg machine
around your workshop? Feathers
will fit on your workbench, in your
car boot and cost a lot less to build
with more easily available parts. You
can always scale up later if the bug
really bites you.
How much does it cost?
As far as hobbies go, this is not a
particularly cheap one, unless you
stick to the lower weight classes. The
ant and beetle weight class robots can
be built for around $200-$300 with
modified hobby servo motors, cheap
radios and batteries being sufficient
to power them. You can have a lot
of fun in these classes and they are
perfect for dads to screw together on
their electronic workbenches with a
soldering iron and hot glue, for their
kids to battle without breaking too
many expensive parts.
The hobby and feather-weight classes start to get a bit more expensive,
since you need more powerful motors
to carry the extra weight, bigger batteries and some serious electronics to
handle the higher currents to power
these motors. Add in multi-channel
radio control and you are probably
heading for $1000 without too much
trouble.
From Light-weight and upwards,
costs really start to climb, unless you
are willing to do a lot of scrounging in
junkyards and surplus shops for used
parts. Fortunately, here in Australia
where the sport is just starting to take
off, the level of competition isn’t very
intense yet, and you have a reasonable
chance of winning with a machine
cobbled together with your home
welder, using salvaged metal
and motors. In fact, that’s how
most of the robots here are
made now.
In the USA, some of the
top-ranked heavy and super-heavy weight machines
have cost up to $45,000,
with CAD designed, custom
water-jet cut parts carved from
blocks of ultra-strong titanium alloys, custom-wound electric motors
and CNC machined gears and drivetrains. Some of the teams show up
with semi-trailer workshops and team
uniforms, since there’s national TV
coverage and fame to be had for winning the championship at the bigger
events. Sponsors will often weigh in
with money and parts to help out the
top TV teams.
Back in Australia, we haven’t
reached that level of professional
competition just yet, so now is a good
time to get into it and have a good time
relatively cheaply before the players
with big dollars move in and start to
raise the competition level bar.
Robot electrical systems
Most combat robots are powered
purely by electricity – batteries,
permanent magnet DC motors and
electronic speed controllers. Some
more advanced designs use petrol
www.siliconchip.com.au
modulated signal. This is then used to
drive high current Mosfets to vary the
power applied to the drive motors, to
move and steer the robot.
Weapon control electronics
Most of the time, robot weapons can
be activated with a simple relay or
two. You will need some electronics to
change the receiver’s servo drive signal
into a relay switch. Some speed controllers have these built-in, otherwise
servo relay adapters are available from
radio control shops (like Silvertone
Electronics).
Electric motors
Some combatants really go into it in a b-i-g way. This pantech is the mobile
workshop for the Team Van Cleve in the US. (www.teamvancleve.com)
engines, pneumatics, hydraulics and
other technologies which we won’t go
into right now. Electrical robots are the
simplest and easiest to construct, the
most reliable and the safest. They are
probably more likely to be of interest
to readers of this magazine.
The components that make up an
electrical combat robot can be split up
into the following categories.
Power source
In most cases, this means batteries.
The most common types of batteries
used in combat robots are either “SLA”
(Sealed Lead Acid) or Nickel-Cadmium (Nicad) batteries. They need
to handle heavy sustained discharge
currents for five minutes, while still
being reasonably lightweight and
physically robust.
Radio control system
Most combat robots use model car
or model aircraft radio control systems
to drive and actuate their weapons.
A basic ramming or wedge robot will
need a two-channel system to drive
the left and right motors. Weapons
require additional control channels
to activate.
Drive control electronics
The Electronic Speed Controller (or
ESC) takes the pulse output from the
radio receiver that is normally used
to drive servo-motors and converts
it into a bidirectional, pulse width
Depending on the weight class,
these can range from small hobby
motors up to huge 15 horsepower
beasts that draw hundreds of amps.
Combat robots are usually made from
motors adapted from some other
application to keep the costs down.
Popular motors can be obtained from
battery-powered screwdrivers and
drills (since they include gearboxes),
windscreen wiper and car thermo-fan
motors, and even electric wheelchairs
and golf buggies.
Wiring and isolation
The wiring of a combat robot is critical. Remember this thing is going to
be pounded on, crashed into, flipped,
crushed and spiked.
The number one cause of failure of
most combat robots is wires coming
loose under the forces experienced.
Also, the wiring must incorporate a
safety isolation switch to totally disable the robot (for obvious reasons) and
be able to handle the large currents
needed by the motors in shoving
matches.
Of course, major damage does occur – that is the name of
the game, after all. It only takes one wrong move to get
your robot caught by an opponent. The idea is to be more
agile, have more power and weaponry and give the
opponent minimal opportunity to cause you damage.
www.siliconchip.com.au
September 2003 13
contact details for the other Australian
builders. We hold regular meetings
where builders can get together, help
each other out and view videos of the
latest events from around the world.
www.abbl.org – an all-states group
with a good chat-forum/bulletin board
to discuss building online.
www.robothavoc.tk – a new site,
aiming to compile information on
the robots and teams from around
Australia; not much content yet but
one to watch in future.
International Sites
Here’s a typical carbon dioxide (C02) setup for flipper control. Remotely controlled via radio, it gives a sudden and powerful lift to the flipper mechanism.
Failsafe
In addition to the physical isolation
switch to remove power, all robots
require some electronics to ensure
that if the radio-control link is lost
for any reason, it will return to a safe
(deactivated) state. Commercial units
are available for this and some speed
controllers have them built-in.
More information
A recent interesting development is
the inclusion of Combat Robotics as an
approved school curriculum course.
Engineering teachers the world over
are finding it’s a great way to interest
students in robot mechanical and electrical/electronic engineering. So many
school or class-based teams started
appearing at the events in the United
States, that a special “Battle-Bots IQ”
organisation was formed specifically
to encourage young builders to do a
school-approved course. Studying a
wide range of engineering disciples
is necessary to build a robot, with the
culmination of the course being to
construct and compete with a BattleBot at an event.
This course has proven to be enormously popular. It is hoped that something similar will occur soon with the
TAFEs and universities of Australia
seeing the opportunity to encourage
young minds in this rapidly growing
field of robots.
Well, that about covers the basics of
Robotic Combat. The rest is up to your
imagination!
14 Silicon Chip
There are a number of “forums”
where you can chat with other builders and enthusiasts, surf a plethora of
web-sites with detailed build reports,
guides, frequently asked questions and
parts for sale. In addition, quite a few
builders use MSN Messenger or ICQ for
online chatting about what’s going on
and to keep in touch. To help you on
the way, here is a list of the best places
to find out more about Robotic Combat.
Australian Sites
www.robowars.org – a Melbourne-based group of builders,
(including the author of this article!).
Check the links page for connections
to other Australian-specific sites and
www.robotcombat.com – the leading
Robot Combat website. Also the Team
Nightmare website, with a huge automatically-updated daily links section
to practically every other robot-related
website out there, allowing you to find
the latest news and content quickly. It
also incorporates the Robot-Marketplace where you can find everything
you need for Robotic Combat, parts,
books, videos, motors, and more.
www.battlebots.com – The producers of the BattleBots events and TV
show in the United States.
www.robotwars.co.uk – The producers of the Robot-Wars TV show in
the United Kingdom
forums.delphiforums.com/Battle
Bot_Tech – The US-based on-line chat
forum; great technical info here.
Acknowledgement
Thanks to Jim Smentowski of Robot
combat.com, John Mladenik and Don
Shiver for permission to use their robot
photos from around the world.
SC
Lightweight bot
“Backlash” can
inflict some
heavyweight
damage!
www.siliconchip.com.au
|