The Care and Feeding of [Battlebots] - It's Alive!

Emissary42

The Battlebots Thread

Some of you may remember some shows a few years back that just might have involved ambulatory power tools tearing each other to pieces to the delight of a screaming crowd. But, the show ended and the images of robots fighting to the death in gladiatorial combat faded into memory; what you may not know is the competitions never stopped. To this day competitions occur across several countries on what is often a monthly basis, with weight classes ranging from 390 pounds all the way down to 35 grams. As I'm in the process of building my first non-affiliated robot, I thought I would make a thread to shed some light on the world of Combat Robotics [A running build report is in the third post of the thread]. Feel free to ask questions about competitions or the building process, and if you think I've forgotten something I can update the OP with additional information.

So, how can I get in on the action?

Spoiler:

It's easy! Believe it or not, a fairly well-crafted tutorial has been made by one of the best teams in the world, Riobotz of PUC-Rio University in Rio de Janiero, Brazil. It is very long and very detailed, and can be downloaded here. NSF56K, the PDF is 28.7MB [I said it was detailed.] I strongly advise reading as much of it as possible (feel free to skim it first though to get a feel for what you should really pay attention to), and particularly read the safety information; these are killer robots we're talking about. In addition, read the rules of the major combat robotics organizations to determine what is and is not legal in their competitions. Related links are in the resources section below.

Where do I get electronics?

Spoiler:

There are a few places to shop, depending on what size of robot you're going to build. The short answer is you can get many of your electrical components from any well-equipped RC hobby site or store, but they won't always carry the best-suited components for battlebots (which endure very rugged conditions compared to other RC vehicles). For that, you will probably need to go to a robotics-specific hobby seller, which I have provided in the resources section below.

Where do I get raw materials?

Spoiler:

Anywhere from Ace Hardware to McMaster-Carr itself. A list of some of the better suppliers for certain materials is below in the resources section.

But how do I make plans/blueprints/CAD Models for my robot?

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There is a wide variety of software programs to choose from to design your robot, but if you're really pressed a good eye and a pencil may be all you need to draft your robot design. If you're as student, you're in luck! Some of the biggest names in the CAD [Computer-Aided Design] industry offer nearly their entire library of software to students for free while they are in school. If you're not, there are still plenty of choices available to you. Again, see the resources section for direct links and more details.

Okay, I have a design, now how do I make it?

Spoiler:

To make a basic battlebot, you need at the very least a small assortment of power tools. To make something more polished takes machining equipment, like mills and lathes. These generally aren't cheap, so to get access to them you either need to work in a machine shop, know someone with machine shop access, find a Hackerspace, or order parts through an online service. Some additional information on manufacturing can be found in the resources section.

Awesome, I have a working battlebot! Where do I need to go to compete?

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Most competitions have websites or participate with The Builders Database to announce their competition times and venues. I strongly advise against impromptu fights without a properly built reinforced enclosure, as even the smallest weight classes can maim or kill.

Resources
Raw Materials:

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McMaster-Carr [Mechanical Parts & Raw Materials]
McMaster-Carr sells a wide range of products, from tools to safety equipment to raw materials. You'll find almost anything you need here for structural components.

Speedy Metals [Raw Materials]
Speedy Metals sells raw materials, primarily stock metal. Their prices are generally better than McMaster-Carr.

Online Metals [Raw Materials]
Online Metals is very similar to Speedy Metals, but they also sell some composite materials (like high density plastics & carbon fiber).

*Also, see below for materials available through The Robot Marketplace

Electronics

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The Robot Marketplace [All Internal Components]
The Robot Marketplace sells basically all the different categories of parts used in battlebots, but most people seem to go there for electronic components and drive motors.

Hobby King [Batteries, {Weapon} Motors, Speed Controllers]
Hobby King is a supplier of RC vehicle parts. Most of their prices are fairly reasonable.

FingerTech Robotics [Antweight & Beetleweight Parts]
FingerTech Robotics sells parts for very small robots. A good place to look for Antweight or Beetleweight parts (primarily motors, speed controllers, and batteries).

SparkFun Electronics [Electronics]
SparkFun sells electronic components for DIY projects. Some of their small components are very well suited to battlebots, like their Batteries and some of their Motors.

BaneBots Robot Parts [Drive System Parts for smaller Battlebots]
BaneBots sells drive motors, gearboxes, speed controllers, and wheels suitable for more lightweight robots (I would guess most of their products work best in robots no heavier than 30 lbs).

Team Whyachi [Large Drive System Components, Advanced Custom Manufacturing]
Team Whyachi is still around, and you can buy some of the best parts for drive systems that exist from their website. They can also make a wide range of parts for your robot through their Bot Shop (note that this may be expensive).

Manufacturing

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eMachineShop [Machining Services and 2D CAD software]
Don't have fancy machines? Have no experience with CAD programs? Not a problem! eMachineShop offers both machining services and a free 2D CAD program that works with their services. (I recommend using this for bulk orders though, as pricing can be steep)

Big Blue Saw [Waterjet/laser cutting services]
Big Blue Saw will waterjet almost any part for you which they are physically able to make with their machines. They accept a few filetypes (DXF, PNG, or GIF) as templates, or you can make a template with their online 2D CAD program. See their site for more details on what materials they offer, or ask them about using a different material than what they usually offer.

*Also, see the above link for Team Whyachi's Bot Shop
**For hands-on work near you (I recommend this, because it'll save you a ton of money), see Hackerspaces.org. This site has a list of hackerspaces worldwide, on all continents except Antarctica.

Competitions

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The Builders Database [aka buildersdb]
This is one of the most used databases for robot, team, and competition information in North America.

The Robot Fighting League
The largest rulemaking entity in the world of North American combat robotics competitions. Competitions are listed on the front page and on their Event Calendar (third link down on their sidebar). Be sure to read their rules!

BattleBots
The most publicly famous North American rulemaking and competition entity. Be sure to read their rules!

*Don't be afraid to search for competitions on Google or any other search engine of your choice. Not all are listed on these sites.

Research Tools

Spoiler:

The Riobotz Combot Tutorial [General Information Source]
A must-read for anyone seriously interested in competing in combat robotics tournaments.

The Robot Fighting League (RFL) Forums
A major discussion location for active competitors. I recommend it as a good place to go see what's going on in the RFL and to ask questions.

MakeItFrom.com [Material Comparison Tool]
Compare materials across a wide set of properties.

Wolfram Alpha [General Information Source & Calculation Tool]
Performs calculations, unit conversions, and gives material properties.

YouTube
Watching videos of competition matches can be very helpful in both early research on robot designs & performance as well as observing real-world driving strategies. Also, watching killer robots on demand is awesome.

Software

Spoiler:

Student Autodesk Software [Free CAD software for Students]
One of the primary flavors of CAD software on the market. I personally use Autodesk Inventor, and it's similar enough to SolidWorks that after learning one you can switch to the next in about a day or two of fiddling around. Go here if your school does not supply student email addresses.

SolidWorks For Industrial Design [SolidWorks Tutorials]
This is an excellent site to learn from scratch or brush up on your SolidWorks skills.

*You can also use the free software provided by some of the manufacturing services previously mentioned. One ghetto-machining trick: print a 1:1 scale drawing of a plate part from emachineshop's software onto a label sheet, then stick it to your stock material. Instant cutting guides.

High-Level Resources [Not Recommended for Beginners]

Spoiler:

How to Make Your Own Miniature Electric Hub Motor [DIY Brushless Outrunner Guide]
Charles Guan's renowned guide on the design and assembly of brushless outrunner motors. Be sure to check the links he refers to both throughout the guide and at the end.

Go Brushless [Weapon Motors & Speed Controllers]
Go Brushless offers almost anything you could possibly want as far as DIY brushless motors go, at least up to a certain size. They also have helpful winding diagrams and other instructions for making your motors.

Open Melt - Open Source Melty Brain [How to make a Melty]
In-depth details on the control systems, design and calibration of Melty-style full body spinners.

Emissary42

Upcoming Competitions


Past Competitions

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PA Bot Blast - 7/17
Location: Columbia Mall, Bloomsburg, PA
Time: Matches starting at 11 AM, ending at 7 PM
Weight Classes Present: Fairyweight (150g), Antweight (1lb), Beetleweight (3lb), Hobbyweight (12lb)
Results: Antweight Champion - Fangus 3.0

International Air Tattoo 2010 - 7/17 to 7/18
Location: RAF Fairford, Fairford, UK
Time: No specific times listed.
Weight Classes Present: UK Antweights (150g), UK Featherweights (13.6 kg), UK Heavyweights (100 kg)
Results:

Schiele Museum "Clash of the Bots" - 7/24
Location: Schiele Museum of Natural History, Gastonia, NC.
Time: Not listed
Weight Classes Present: Fairyweight (150g), Antweight (1lb), Beetleweight (3lb), Non-Combat Bot Hockey (12-15lb)
Results:

Gulf Coast Robot Sports 6 - 8/14
Location: Bradenton, Florida, at the Hobby MarketPlace/Robot MarketPlace Retail Store
Time: Matches starting at 11 AM
Weight Classes Present: Fleaweight (150g), Antweight (1lb), Beetleweight (3lb), Unmodified RC Toy (special)
Rule Set: RFL

Robot Battles 39 at Dragon*Con - 9/5 to 9/6
Location: Hyatt Regency Hotel & Conference Center, Atlanta, GA
Time: Matches starting 10 AM on Sunday the 5th for Antweight & Beetleweight class robots, Matches starting 12 PM on Monday the 6th for 12 & 30 lb Sportsman weight classes.
Weight Classes Present: Antweight (1lb), Beetleweight (3lb), Sportsman [open-air safe] 12 & 30 lb classes.
Rule Set: Special

Emissary42

Build Report
Antweight Class [1 lb], Name: Kinetic Discourager Glass Cannon
Weapon Type: Vertical Disk
Competitions: Dragon*con Robot Battles 42, 0-1 win/loss record

2011:

9-1 to 9-2:
BUILD ALL THE THINGS. Over the course of one evening and one 16 hour caffeine-fueled extravaganza of robot construction, Glass Cannon finally came online. Competition notes, pictures, and final details will be in the thread-resurrecting post below!

7-17:
After a stupendous amount of nothing happening, I've finally got something to put up here again. For the time being, I'm abandoning the custom motor for an off the shelf brushless outrunner. In the future I'd like to get the custom motor running, but I'd prefer to have a working robot for Dragon*con this time around. I should have some CAD assemblies done in a few hours, and from that I can order some materials for the updated layout (lots of plastic). Once the materials are ordered, I'll put up a general update post.

1-3:
Some new photos will be up shortly. What's happened in the intervening months is a whole lot of nothing; I did, however, press fit the weapon disk to the weapon's motor can and determine that I needed to make new side pieces. Initially I believed the 1/8" aluminum would be thick enough for proper fastening, and I've now realized that wasn't such a good idea. New side pieces will be designed and then machined from 1/2" polycarbonate, hopefully two weeks from now.

2010:

9-2:
Due to unfortunate delays, the robot will not be done in time as planned. However, there will still be a great number of robots in attendance at Dragon*Con Robot Battles, particularly some impressive creations in the 30 lb class.

8-12:

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And into this ring he poured his cruelty, his malice and his will to dominate all life: one ring to rule them all.

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Due to a sudden increase in demand for parts to be made in the machine shop, last week was pretty much devoid of robot parts. Fortunately, the past few days have been fairly light and I've been able to pump out the most critical components of the robot. Both sidewalls are now done as is the motor can, baseplate, and weapon shaft. Tomorrow will be motor endcaps, drive struts and carbon fiber exterior and interior plating - more photos pending.

The photo above is just after removing the weapon disk from a heat treating oven set to 1742 degrees Fahrenheit. To treat S7 steel for use in battlebot weapons, you first superheat it at that temperature for 30 minutes, then quench it in oil. Once cooled, the part is then de-greased and re-heated to 600 degrees for two hours, then allowed to cool in open air. This produces a very particular grain structure in the metal that provides sufficient hardness and toughness for the demands of the application - in this case, knocking the crap out of little metal objects.

7-27:

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Completed Disk:

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Work begins tomorrow on the other components in the weapon assembly.

7-26:

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Work on the disk continued today, as Friday was distinctly lacking in downtime on the machines. Currently, the weapon disk is a bit over a third of the way done and should be completed tomorrow. Here are some pictures from the machining today: (all spoilered for HUGE)

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For size reference, the tool you see in the first two images is 0.25 inches in diameter. A notable side affect of milling (or lathing) is the production of thousands upon thousands of tiny chips of metal. In this case, they are all quite safely contained within the mill enclosure; however, this is not the usual state of affairs, and it is not uncommon for you to keep finding small chips of metal on yourself for several days after you finish machining.

In other news, a few days ago I let the cat out of the bag: KD's first competition will be at Dragon*Con this September! My current aim is to have at least all machining done within the next two weeks, leaving the remaining time for electrical work, assembly, and driving practice (yay fighting the gyroscopic effect of a large spinning mass!).

7-22:

Spoiler:

The first machining began today on the weapon disk, which will be completed tomorrow (Friday). Also coming down the pipeline are the other weapon components, since I now have all the materials for those parts. Pictures (and possible videos) of the progress, along with CNC G-code for the part setups will be coming shortly.

7-19:

Spoiler:

The aluminum, tool steel, and mild steel rod for the motor can arrived today - this means machining will begin within one to two days, even if that's just preparing the stock (which will probably start tomorrow). The remaining materials should arrive tomorrow or the day after, meaning the robot will likely begin to be assembled by the end of the week or so.

7-16:

Spoiler:

The first piece of material arrived today, 1/32" thick rigid carbon fiber plate from McMaster-Carr. This particular material will be used on the top of the robot and on the rear angled portion.

In addition, after much consideration and debate the robot now has a name: it is the Kinetic Discourager/Kinetic Discouragement Device, shortened to KD on the robot itself. The name was inspired by the Portal 2 feature/environmental hazard known as the Thermal Discouragement Beam.

7-14:

Spoiler:

The stock material for the robot got ordered today: 7075 aluminum plate, S7 tool steel plate, 4340 steel rod, UHMW polyethylene rod, rigid carbon fiber sheeting, and a few thicknesses of polycarbonate stock. In fact, as of one hour before this writing I received the shipment notice for the whole lot. Since it's shipping on ground (and in an odd stroke of coincidence for this forum, most of it from Seattle), machining will start up next week on the components. I'll be doing the machining personally, but I went over the design today with a machinist I work with to work out some kinks and get a better plan for how I'm going to go about making the different parts. Fortunately, the most major changes were to alter the internal radii on where the weapon disk meets the weapon motor's can (larger end mills [tool heads that appear vaguely similar to drill bits but are intended to cut both down and sideways] hold up better to stiffer materials like steel, which is the reason for the change).

The robot still needs a name.

7-13:

Spoiler:

Fastener work and wire routing is now done! Onward, to machining! The primary mills that will be used are this one and one of these (the K3, specifically). While I'm waiting for the stock aluminum, steel, and plastics to arrive I'll be producing G-code with a program called camworks for each part. Fortunately, it's pretty easy to use (more on that when I start coding).

As an aside, the robot needs a name. I'm open to suggestions.

7/11:

Spoiler:

Today's been a bit of a slow day as far as progress goes, but I did get a few things further along. For one, I've now got most of the fasteners modeled into the final layout. This has revealed a few areas I need to play around with to ensure that the material doesn't get too thin, but I'm confident I'll tackle that in very little time. Second, I changed the bottom plate on the main chassis from aluminum to polycarbonate. This gets me some significant breathing room as far as weight goes while sacrificing some strength. Fortunately, that trade-off is very reasonable (many antweights are made entirely of polycarbonate and other assorted plastics). Third, I finally got the weapon motor's stator wound.

One feature of the robot that some of you may have noticed is the distinct lack of any transmission hardware - like a pulley & belt - from the weapon to a motor. In this case, that is because the weapon itself is a motor. The weapon's CAD assembly is broken down into four unique components: the disk, the endcaps, the axle and the motor can. The motor can is normally hidden from view by the endcaps, but here's what it looks like with one removed:

Spoiler:

The particular flavor of electric motor this falls under is a brushless outrunner; it is brushless in that it does not use any physical brushes to deliver power/switch current directions to the wire coils on the stator [the stationary iron core that is used to produce the electromagnetic fields that make the motor spin], and the term outrunner tells you that the outer can of the motor itself is what turns, not the axle. The reason I chose to use this setup was to save space (and therefore weight) on the robot. If you're more curious about the specifics on the function of brushless motors, check out Charles Guan's brushless hub motor design & assembly tutorial under the high-level resources above.

Today I wound the stator for the motor, which is an easy but tedious process. The stator itself is a standard nine-pole stator (most commonly found on the insides of CD & DVD drives), which gets me three sets of three poles per stator. Each pole has eighteen clockwise winds of wire (nine outward, nine back inward) for a total of 54 turns per phase. This should result in a decent amount of torque for a short spinup time on the weapon. Now, none of this probably makes very much sense to many of you, but the really dumbed-down bad-explanation version is fewer turns of wire = less torque and more speed, while more turns of wire = more torque and less speed. In reality, it depends on all kinds of variables like the strength of the magnets in the motor, the resistance of the wire, the current supplied, etc [the tutorial I mentioned a paragraph back explains all of this far better than I can]. Here's the result of today's labors:

Spoiler:

A bit underwhelming, but it's one more step toward the completed product. The little silver block is one of the twelve magnets that will be affixed to the interior wall of the motor can. No, that is not an over sized D20.

7/10:

Spoiler:

As I mentioned in the OP, I've been working on a personal robot in the one pound [antweight] class. It's currently far enough along that I'll begin machining raw material sometime this week, and I already have all the necessary electrical components.

Images of the latest CAD assembly under spoilers:

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Front View:

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Rear View:

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Side View:

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Top View:

Current Progress:

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Notably missing are the wheels, which I have neglected to add to the model thus far (their size and weight was still taken into account for the layout, so they'll be left out except for beauty-renders). Currently the layout is a basic Vertical Disk design, not dissimilar to the old heavyweight Nightmare. The disk is hardened steel, with a more recently common mono-tooth design (one tooth permits a doubling of weapon RPM while still achieving the same "bite" of a two-toothed weapon). The disk itself is designed to be balanced despite the asymmetry. The other primary materials are Aluminum (chassis), Lexan/Polycarbonate (wheel struts), Carbon Fiber (on the top & rear plates), and UHMW plastic (weapon endcaps).

Right now, I'm adding the final fasteners to the model and one or two additional components & features to the parts before prepping to switch over to CAM programming. CAM programming is how you switch from a digital computer model to encoded instructions a CNC machine can interpret to automatically cut the part from stock material.

Mr_Grinch

Surprised this thread hasn't had more interest, just blue dotting it to see how things go. I'd love to do something like this but:

a) It's nowhere near as big in the UK and
b) My time and money is at a premium due to marriage/house purchase!

Keep updating the thread though, I'm looking forward to seeing some pics as you progress.

Improvolone

I would love to get in on a community designed machine. A hive mind robot if you will.

Emissary42

Mr_Grinch wrote: »

Surprised this thread hasn't had more interest, just blue dotting it to see how things go. I'd love to do something like this but:

a) It's nowhere near as big in the UK and
b) My time and money is at a premium due to marriage/house purchase!

Keep updating the thread though, I'm looking forward to seeing some pics as you progress.

On a) I suspect it depends on where you look - I just googled around a bit, and I discovered a fairly major event is about to occur this coming weekend (heavyweights and all) in the UK. I'll admit, it's hard to find some events though - the vast majority are for the small weight classes run by local groups that don't have a very good web presence, so unless you're in the know you never hear about them.

Spoiler:

As an aside, it looks like there's an interesting difference between UK competitions and US competitions based on their rules & arena types. The robots in the US overwhelmingly favor robots with spinning weapons, while the UK overwhelmingly favors launchers and lifters. On closer examination, I've concluded this is because the big arenas in the UK are more lightly armored on some surfaces than US arenas; UK arenas have 6mm [nearly 1/4"] polycarbonate (bulletproof plastic) walls, while US arenas have around 1.5 inches [38.1mm] of the stuff. As a trade off though, US arenas very rarely have a lot of cool arena hazards.

Improvolone wrote: »

I would love to get in on a community designed machine. A hive mind robot if you will.

That would be pretty cool.

BigBlueSaw

Thanks for the link, Emissary42.

Group designed bots have been suggested before, but there's a few problems to overcome. Getting everybody on the same CAD package is one. Also, even with online machining services, there's still a lot of assembly, testing, and tweaking that goes into building a fighting robot, and that must be done in person.

Mr_Grinch

I don't think the UK scene was helped much by the God awful Robot Wars tv show we had, the commentary was horrendous:

http://www.youtube.com/watch?v=_e4cHWS2758

I think all anyone really remembers of the UK show is this little dude because it actually did severe damage:

http://www.youtube.com/watch?v=lzraVXP-5KQ

Emissary42

Oh, trust me, cheesy announcing seems to be one of the major traditions in a fair number of competitions. Fortunately, the damage the robots are capable of dealing has increased at a rate proportional to that cheese:

http://www.youtube.com/watch?v=Gw0KbLlJYfU

http://www.youtube.com/watch?v=vUtbt5vEt8M

Improvolone

I've always wanted to see a giant rolling ball/pill shaped object.

Emissary42

Improvolone wrote: »

I've always wanted to see a giant rolling ball/pill shaped object.

Then you're in luck! Meet ROFL.

GMaster7

Those videos... Are SO awesome. Good luck with this project!

Emissary42

Fun side effect of milling steel: the machine attempts to mimic a vuvuzela

http://www.youtube.com/watch?v=Z56DtS5V2nI

In other news, I've finally been able to track down news from a competition that took place two weeks ago. The Pennsylvania Bot Blast tournament on July 17th went off well, and the winner in the antweight bracket was Fangus 3.0. Here it is fighting... itself?

http://www.youtube.com/watch?v=3gn8pdhTMdk

electricitylikesme

Man those saw-blade / spinning heavy thing robots are god damn terrifying.

Emissary42

For much of the past year the robot has sat in its box due to a combination of coursework, lack of machine access, and a need for a radical redesign of the chassis.

Summer 2011
In a combination of idle/unallocated time at my internship and at home over the summer, I was able to produce a new chassis layout. This has vastly simplified its construction, and was the last piece I needed before starting up fabrication again.
The first components made were endcaps and assembly tools for the weapon hub motor. Going off on a bit of an adventurous/insane streak, I decided to 3D print them; after all, if you have access to a 3D printer why not take advantage of it? Once the parts had finished printing, I went about finishing the assembly of the motor. In this case, that meant gluing the magnets to the motor can and applying a protective layer of epoxy to the stator windings to prevent wear and short circuits.

Spoiler:

If you'll recall, in this robot the weapon itself is a motor - specifically a brushless outrunner - in order to reduce the number of components to limit the possibility of damage and to decrease weight. Once the whole thing was together, I mounted the axle in a lathe (the most convenient stationary object I had at the time), attached a power supply, speed controller, and servo tester, and turned it on:

Spoiler:

Personally, I was amazed at how well-balanced the entire thing turned out. Quite pleased with my results (including an eviscerated coke can), I proceeded on to the robot's chassis. Since the endcaps had turned out well, I decided to give the 3D printer a bit of a bigger workout:

Spoiler:

While the print turned out quite well, I wasn't satisfied with the rigidity of the final part, and decided to make a new frame from polycarbonate [aka bulletproof glass]. It was around this time that the new name, Glass Cannon, was given to the robot as several people were concerned the printed chassis would shatter violently if struck by a spinning weapon. With the change to a polycarbonate frame, the risk of violent botsplosion had dropped but the robot's appearance matched the name much better.
With my internship winding down and packing for heading back to school well underway, I boxed up what I had managed to finish.

Fall 2011
With Dragon*con fast approaching, I needed to make the new chassis quickly. I made an order with expedited shipping from onlinemetals, and then waited. And waited. And then finally heard that they accidentally sent my polycarbonate to my billing address around 1000 miles away. Fortunately, McMaster-Carr is close enough that I was able to make an emergency order and have the polycarbonate I needed arrive the next day.
It's worth noting that I'm not the only person who builds personal battlebots at my school. The owner of the antweight [1 lb] DDT and beetleweight [3 lb] Cake is also a student here, and we both volunteer in an open machine shop on campus. Some of his friends wanted to get in on the action as well, and Internet Famous (featured in MAKE magazine, Popular Science, on Engadget and hackaday.com) Charles Guan was visiting and making use of the facilities here for his robot, the antweight [1 lb] Pop Quiz. This sets the stage for a two day caffeine-fueled robot building extravaganza to finish Glass Cannon, repair Cake, DDT, and Pop Quiz, and build three of what were dubbed 'Ass robots', perhaps better understood by "robots we pulled out of our ass in two days". I'll give a little run-down on each before continuing with Glass Cannon:

DDT & Cake

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DDT was just about ready to go, and only needed to have some wiring worked on and maybe one or two parts changed out. The story was very much the same with Cake. Here's a picture with Cake on the left and DDT on the right:

Pop Quiz

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Pop Quiz is one of the thinnest antweights ever made, and this year was sporting a 3D printed frame. I believe work on it this year was mostly soldering. More information can be found on Charles' website, www.etotheipiplusone.net

The Assbots

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The first of the Assbots was built with Pop Quiz' old frame and electronics, minus the weapon and motor. For shits & giggles they attached a propeller to the end of the motor they mounted in, and were shocked when it actually picked up off the ground and flew. This resulted in the name Prop Quiz, and a potentially new type of battlebot that uses some clever driving and a lack of torque neutralization to drift into an opponent with the whole robot spinning. I'm still looking for the video of the controlled drifting they managed to pull off, but here's the first time it took off:


The second Assbot, Melty Butt, was a translational drifter or "MELTY" robot built for the hell of it out of whatever was on hand. It worked pretty well, except it was made of wood, and wood is not meant to hit things at a few thousand RPM. The image is before its fight, and after is its video:

http://www.youtube.com/user/XoWang#p/u/3/-buqqEaRkHM

The third Assbot, "$20,000 Per Year Mechanical Engineering Degree", was built by Charles in 30 minutes one night with whatever was in arm's reach. The description by its creator: "the hand is symbolic of begging for money and the weight of student loans; the duct tape wrapped around the galvanized roof flashing is representative of the challenges students face in pursuit of fulfilling their engineering degree requirements; the threaded rod represents front-end ballast mass."

On Thursday afternoon and Friday, I used the waterjet machine to cut out the polycarbonate pieces for the frame. It's quite a loud machine to use, but it's easily becoming one of my favorite ways to make parts. Here's the baseplate & top plate being cut on the machine:

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Once that was done, I had to drill and tap some holes in the frame pieces and then bolt the whole thing together. Here's what it looked like somewhat later on Friday, waiting for the soldering station to open up:

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Once soldering was done, I was able to turn it on for the first time. Unfortunately, it was at that point that I discovered I had some kind of problem with my transmitter; the aileron potentiometer was not responding, and it occasionally entered periods of erratic uncontrolled activity (which is BAD for BattleBots) I was able to solve the potentiometer problem by changing some channels around, but the erratic behavior still persisted.
After a bit more work Saturday evening, the robot was finally done. Here's how it looked at the competition:

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The Venue:

Spoiler:

Due to an incredible turnout of 36 entries, the competition on Sunday had to be switched from double elimination to single elimination in order to fit into its normal time slot. I was the third fight, against a robot called Black Mesa, with 4-wheel drive and a circular saw. The match was pretty good, I got in a solid hit on one of Black Mesa's wheels, popping it about a foot vertically and away from my robot, but I was eventually pinned against the wall during a transmitter fault, where Glass Cannon's baseplate was sawed completely through and the weapon speed controller suffered damage, causing a power failure to the receiver. Realizing that my robot was dead and further damage would likely result in a battery short and minor fire, I tapped out. Here's the carnage:

Spoiler:

Not only was the signal wire to the weapon ESC cut, the main power wire was damaged and a capacitor was nearly cut in half along its length.

The week after the competition, I replaced the damaged electrical components and changed out the polycarbonate top and base plates for 7075 Aluminum plate of the same thickness. The robot is still comfortably under the weight limit, and is now significantly more resistant to saws. Further updates to come include embedding LEDs in the polycarbonate side panels, new weapon endcaps, and possibly laser-etched artwork into the aluminum top & base plates. Additionally, I'm troubleshooting my transmitter and will hopefully be able to drive it around again shortly.

Shanadeus

I am glad this thread is alive.
Loved robotwars as a kid.

Skoal Cat

I can't even fathom a 1lb robot duel.

Emissary42

Skoal Cat wrote:

I can't even fathom a 1lb robot duel.

They're different, I'll say that. The nature of how battlebots work is their power output isn't proportional to their weight; lower weight classes can be more powerful per pound than most heavyweights. This means fights with smaller robots are frequently much more dynamic, in the physical sense. Robots with active weapons throw each other all over the place, both because it takes less to throw small things around and they're so powerful for their size. Good examples below (Cake & DDT video compilation from the competition):

Camo5

I made an antweight (1 lb). I still can't fathom 150g or 75g bots XD

here's a video of it: