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How to design and build a combat robot

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Combat robots have been entertaining and amusing since before they were popular on Comedy Central. A while back I undertook the challenge of building a couple of combat robots (a 30lb and a 220lb). Regardless of the size of the machine the steps in the process are the same. This Instructable will walk you through the steps and provide you with resources to help with the machine and give an understanding of what is involved using my 30lb robot as an example.
 
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Step 1: Decide what size robot you want to build

Picture of Decide what size robot you want to build
Combat robots come in many sizes from 75grams to 340lbs each one of them has their pros and cons. The first thing to do when thinking about building is to find the competition which you want to compete and see what weight classes are going to be there, because what is the point of building a bot you can never fight. Listing of robotic competitions are available on http://www.buildersdb.com and http://www.robotevents.com.

Large robots: 60lbs +
There is nothing like the thrill of seeing two large machines hitting each other with the force of a small car wreck. When most people think of combat robots it is these larger machines which first cross your mind. If you are fortunate to live near one of the large robotic events these machines can be fun builds, but at the same time the level of engineering required can be quite difficult. These large machines can also cost quite a bit of money. When you commit to building a machine this size you are committing at least $1000, and in many cases much more. I would estimate that your average heavy weight (220lbs) would cost a builder $4000-$5000 to build a competitive machine, and it is not uncommon to see builders spend upwards of $15,000+ on their machines over the course of a few years. In the days when combat robotics was televised there were many sponsorship opportunities which would subsidize the cost, unfortunately now as a builder you will be on your own.

On the good side of larger machines is that many times you can find surplus parts online which can reduce the cost of the machine. Using off the shelf components such as items from http://www.teamwhyachi.com/ or http://www.AndyMark.biz can help make things easier. There are more of these components available for larger machines. Those Larger machines also have the added ability for service, fixing a machine is much easier the larger it is. Building a large robot can be both fun and enjoyable and you wont regret being able to say "I have a 120 lb battlebot in my garage"

Small Robot:

Building a small robot can be alot of fun but also a good challenge, with a restricted weight limit it makes every part on the machine to be critically thought about and designed. Most people are drawn to these smaller machines because of the frequency of competitions for them as well as the ability to transport them easily. While it is the common misconception that small robots are cheap they can be just as expensive as their larger counterparts. Alot of times the small electronics required for these can cost quite a bit as compared to larger components.

weight classes (list from wikipedia):

  • 75g- Fleaweight
  • 150g- Fairyweight (UK - Antweight)
  • 1 pound (454 g) - Antweight
  • 1 kilogram (2.2 lbs) Kilobot
  • 3 pound (1.36 kg) - Beetleweight
  • 6 pound (2.72 kg) - Mantisweight
  • 12 pound (5.44 kg) - Hobbyweight
  • 15 pound (6.80 kg) - BotsIQ Mini class
  • 30 pound (14 kg) - Featherweight
  • 60 pound (27 kg) - Lightweight
  • 120 pound (54 kg) - Middleweight
  • 220 pound (100 kg) - Heavyweight
  • 340 pound (154 kg) Super Heavyweight

Whoo! Love the robots. Wish I could build one. Go to cameltalk.webs.com or puttyfun.webs.com!

im building a three pound robot but I don't know what the weapon can be so I need advice on what the weapon can be also this is my first battlebot
what is fabrication needed for I saw some of the other robots and one of the steps was fabrication I don't know what that is
for a 3 pound robot what do you think the weapon should be I need help on this one
micsteel89 months ago
I want one that talks, fights, and does anything for me
Jaxun12 months ago
Robot combat... we train them to be fighters, then when they get smart enough they revolt for us making them fight. Nice Instructable. I'll definitely be building this in my spare time.
aroadiez1 year ago
thatz cool
I'm trying to build one of these this summer. Do you think piston-mounted spikes would work or two horizontal blades?
grenadier4 years ago
I built one, imo it sucks and i want to rebuild it. But i have no reason to... To me it seems combat robots are dead, except for a couple annual matches in CA and FL. All the websites on combat robots don't seem to be updated since 2002. (bad grammar) Now, i have this crappy bot sitting in my garage, and i have no idea what to do with it. I could use all of the electronics to make something, but what?
Robot Battles (http://robotbattles.com/) in the southeast US is still going stong.
Most of them are, unfortunately. However, the RoboGames in San Mateo, California, are still on. Apparently there are 50+ events including combat soccer, and lego bots. Even if you don't want to rebuild it as a battlebot, you could probably use the components for a soccerbot or something.
which type of motor should be used for cutter?
(removed by author or community request)
 But what if someone has an axe?....
 what if the robot has an axe?
 What if your own robot has a badly placed axe?
what if someone else's axe was badly placing your robot?
What if someone else's badly was robot your placing?
WTF?
can cover the bot with gi sheets instead.....
u can also increase thi thickness of ur propulsion wheel
dhill102 years ago
what does the orange robot do at the top of this page
dhill102 years ago
how do u make the round one can u put steps on this website
You show the design process really well! You really know your stuff! I am currently building my own combat robot, the blog is...

http://eventorizon-maelstrom.blogspot.com/

if you want to check it out. Tell me what you think cos you definitely have the construction of your bots down to a fine art, especially cos you trust your own CAD skills enough to have the parts custom cut!
would this be a good idea 2 circular saws on sides
nailgun on top
made of stainless steel
and a spiked rammer with a strong motor too power it
how much do u think it would cost plz reply
tobyscool3 years ago
Could i just buy one simple rc car and get the inside and change the armor and put a weapon. because im cheap :D
REA3 years ago
what about programing it? where does one begin with programming?
That won't be necessary if you build with enough hardware. RC receivers don't need programming and neither do the servos. The relays, maybe, but the robots aren't autonomous.
Dannne113 years ago
can i just put the fuse between the wires, instead of having a breakout board??
your dog4 years ago
Hi!
I was wondering..... where could you get a base- where did you get yours?

I've all ready seen
http://www.inertialabs.com/
http://www.robotmarketplace.com/store.html,
http://www.battlekits.com/

P.S.-I'm trying to build a drum bot.
gneedel (author)  your dog3 years ago
I built mine. Get raw aluminum plate and cut it out. If you don't have access to fabrication tools (mill, waterjet, laser, etc) you might be better off buying a pre-made base. The trade off will be that you will have to make do with what you can buy instead of doing a custom solution.
would you be willing to make this c.a.d downloadable?, i recently received a autodesk setup and id really like to see a properly made fighting robot cad (thats what i intend to use it for) befor i make mine so i get a basic idea of what to aim for, ta :)
gneedel (author)  team-orr-robotics3 years ago
I would be glad to give you the CAD models for the machine as soon as I get a chance to find them. They are on some portable hard drive somewhere as I have changed computers since then. email me greg at robogreg dot com and I will do my best to send them to you.
hi, i sent a email...wondering if it got through?
gneedel (author)  team-orr-robotics3 years ago
I got it. I am working on finding the files when I get some time.
Dannne113 years ago
Why do I need a Breakout board???
gneedel (author)  Dannne113 years ago
you need a breakout board if you want to use any type of fuses to protect your speed controllers.
GianniMora4 years ago
about how much money would a mantisweight battlebot cost if i had if ihad like the crapiest matirials for it and how much would it costif i had the best matirials on it.


szechuan535 years ago
unfortunately, i have highly limited resources, a max of $200 at any given time, if i'm lucky. :V(
gneedel (author)  szechuan535 years ago
it is possible to build a bot with 200. There are plenty of cheap components. You could build a sub $200 bot using motors taken from Harbor Frieght $15 drills. Use the battery packs from the drills to power the bot. For remote controls you can find some cheap things on ebay and from a company called GWS. You can view some of their components on http://www.banebots.com, which is another source for inexpensive robot materials.

For sub 200 robots you will be looking at the 3-12lb range of classes.
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