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Real Steel: The Secrets to Winning ComBot Battles

By Wesley Fenlon

Combots Cup competitors Gary Gin and Orion Beach talk about creative bot design, the importance of spare parts, and heavy metal destruction.

I watch as Orion Beach and the rest of team Electric Boogaloo unbolt the armor plating from the front of their 200 pound robot. Their battle against Last Rites--easily the most destructive heavyweight combatant at Combots 2012--is about 15 minutes away. Without its armor plates, one hit from Last Rite's 75 pound horizontal bar spinner would rip Electric Boogaloo to pieces, slicing through its thin chassis and smashing its tightly packed batteries, drive motors and other components to bits. But Beach isn't sending Electric Boogaloo in naked: He's swapping out its titanium armor for heavier quarter-inch thick abrasion-resistant steel plating that will, hopefully, stand up to Last Rite's 2200 RPM spinning blade.

Building a killer robot isn't all it takes to win the Combots Cup. Adaptability is just as important--knowing how to face wedge bots and lifters and spinning blades, being able to swap out parts on-the-fly between brutal matches of robot-on-robot violence. The cage may play host to the carnage of Combots' heavyweight bouts, but the pit is where the real action is. Tools, battery packs, lightweight robots, laptops, and snacks cover the rows of fold-out tables laid out for the Combots contestants. The pit bustles with activity as bots line up for their next bouts and battered wrecks are hauled from the arena for emergency repairs.

Last Rites in a ComBots event in 2009.

The pit reflects how members of the Combots community spend 99 percent of their time in the hobby: Building, testing, tweaking, fixing, and talking about bots. The other one percent of their time belongs to the cage, and a destructive three minute match can undo the months of work that go into each robot.

As fun as watching those bouts can be, a few hours in the pit reveals something more interesting: the preparation that goes into the annual trek to San Mateo. Beach and the other contestants had all the time in the world to build their robots before the competition, but they often only have 30 minutes or an hour to rebuild their robots between matches.

Boogaloo Does Battle

Though Combots Cup VII is only Electric Boogaloo's second competition, it stands a good shot at the Combots Cup title. The bot has just completed a match against Original Sin, which has won the heavyweight crown at Combots and RoboGames seven times. While team Electric Boogaloo begins bolting on heavy armor, Original Sin driver Gary Gin is frantically replacing virtually every part on his robot. Electric Boogaloo just tore it to pieces.

"Vertical spinners do great against wedge robots," Orion Beach tells me over the phone a few weeks after Combots Cup VII. Recalling his match against Original Sin, I think this is an understatement. In designing Electric Boogaloo and its 50 pound vertically spinning steel weapon, Beach and his friends decided to play the odds. There are a lot of wedge bots in the Combots competition, so they aim to target the weaknesses of the greatest number of bots.

The plan worked beautifully against Original Sin, but Last Rites is no wedge robot. As Electric Boogaloo and Last Rites are rolled into the cage, Combots organizers hand out earplugs to everyone watching from the pit. They promise this fight will be loud. They're right.

Every hit sends the pair of bots careening across the arena, but they somehow manage to keep pounding away on one another for more than two minutes. For all the protection it offers, Electric Boogaloo's AR400 plating may as well have been tinfoil. Last Rites tears into the plating and eventually leaves Beach's robot so battered and mangled that it can no longer move. Electric Boogaloo is sent to the loser's bracket, but it's too beat up to keep fighting.

"After our Last Rites fight we had a bunch of cracks and broken pipes in our frame," Beach tells me later. "So even if we had beat Original Sin a second time and fought Last Rites in the finals, it would've been really tough because there was hardly any wedge to bolt back on. He'd already cut through most of it."

If the damage hadn't been so severe, Electric Boogaloo likely could've recovered. "I always try to have spare everything, but that's not always practical," Beach explains. "It's frowned upon to have a whole second robot built and ready to go, that's not really allowed, but you can certainly change out all the parts and whatnot. So we always brought extra steel tubing for the frame and always had extra drive motors and spare speed controllers and spare batteries, and all the tools to take them off and put them on as quickly as possible."

Beach follows a simple mantra while building and working on bots: "Whenever you buy something, just buy extra. Whenever you make something, just make another one."

Gary Gin follows a similar philosophy with Original Sin. "We always have at least three or four complete sets of tires because they're exposed," he tells me over the phone after taking home second place at Combots Cup VII. "Some people don't bring a lot of spares. I think that does take a lot of my time...And I always have extra drivetrain pieces, extra wedges--I've got two sets of the triple wedges and a couple single ones--always at least two of the plows [used to fight Last Rites] ready to go."

Both Gin and Beach come to Combots armed with socket wrenches, screwdrivers, and replacement parts galore, but their planning goes deeper than that. For Gary, designing a modular bot, with easily exchangeable parts, was a priority. For Beach, having the flexibility to design around the strengths of other bots--like Last Rites--informed Electric Boogaloo's design.

Building the Bots

Unbelievably, after being ripped apart by Electric Boogaloo, Original Sin lives to see another match. Gin carts what's left of the bot back to his table (it undoubtedly weighs less than the 220 pound weight limit, at this point) and begins replacing parts. He and his team work while a succession of bots duke it out in the cage. They work while Last Rites dishes out a familiar dose of punishment to Electric Boogaloo. After an hour, Original Sin is back--minus most of the parts it was using the hour before.

"The last three sets of competitions I've had spare frame rails," Gin says. "Because Last Rites was able to slice through them, I didn't want that to happen during a competition and not be able to fix it. When I was building replacement rails, instead of just building two, I built four, two on the bot and two spares. After that Electric Boogaloo fight we ended up replacing not just the frame rails and a new wedge, I had to use a previous top, and the back end was an older version too. We pretty much changed everything but the base plate, electronics, motor and speed controller."

The secret to Original Sin's modularity actually stems from what was once a weakness: welding. "At the time I started building these I didn't know how to weld," Gin says. "And you can tell if a guy doesn't know how to weld, he has a lot of nuts and bolts holding everything together. But guys who are good at welding, they weld everything together. It's what they're good at, and it makes a much stronger structure. But it makes it much harder to take apart later on."

While some parts of Original Sin are now welded, it's still modular enough to have parts swapped in and out quickly. That's been important to Gin since he started competing in robotics circles back in the Battlebots days.

"I remembered an old Battlebots called Biohazard who was one of the top heavyweight guys for a long time," he says. "I saw on the show that it took him something crazy like eight hours to change a tire. And I just thought, well that's ridiculous, we won't be doing that. He had these tiny wheels that were way inside, and he had to take a ton of things out to get to them. Whereas on Original Sin, you can change a tire in 15 seconds if you have to. It's kind of NASCAR style."

Electric Boogaloo doesn't share Original Sin's extreme flexibility, but both bots have special attachments designed to fight Last Rites. Boogaloo's vertically spinning weapon mount and single-tooth design are actually scaled up--big time--from another robot Beach designed. It weighs three pounds.

"On the smaller robots I learned how to balance a single-tooth weapon," Beach says. "If you make it totally completely asymmetrical, it tends to have more harmonic problems. The center of gravity can be in the middle and it'll balance on a shaft statically just great, but when you start spinning it up it'll vibrate at certain points on the RPM range and one thing that I found that really helps that is making it symmetrical along one axis."

The previous fight between Last Rites and Electric Boogaloo

Electric Boogaloo's vertical blade gives it room for sloped or curved armor in the front, which is better at reflecting hits from other bots, minimizing the impact and damage done by their weapons as much as possible. Of course, that didn't quite work out in the battle against Last Rites, but Beach knows why.

"We made some changes between Robogames and Combots to try to be better against Last Rites... We had those [curved wedges] not as secure at Robogames and they got ripped off really fast by Last Rites. He was running a bigger blade, a longer blade, and we were actually much more effective against that blade. ... He just couldn't spin up and get control of his robot after we'd come together and hit. I was able to drive in and take some shots on his wheels and on his chassis and at Robogames was able to break both of his drive motors out of his chassis, so they were just flopping around.

At Combots, because of the extra mounting stuff, our wedges stuck out about an extra inch farther and so I think that might have hurt us a little bit when it came to weapon-on-weapon stuff because he could more easily hit our wedges and not our weapon. What we really want to do is hit him up into the air so he hits the ground. One time at Combots we got that to happen. That's when he punched a hole in the floor. So that's what the swoopy wedges are for, to kick his blade up into the air. But at Combots he was running a big heavy steel blade, and it pretty much just sliced through our armor, which is pretty tough stuff."

The heavy AC400 armor plating requires compromise, however: Because of the heavyweight class' 220 pound weight limit, Beach has to swap out his heavy steel spinning blade for a lighter and softer aluminum weapon. But with such a young robot design, things are still changing for Electric Boogaloo. By next year's RoboGames, Beach hopes to have a new armor design to maximize protection within the weight limit.

"Right now the current plan is the fix up the aluminum weapon and make some smaller curved wedges that will go over the top of the flat steel wedges, so it'll kinda be like two layers," Beach says. "We'll probably be able to make it thicker cause it'll be smaller. ... We want to hit [Last Rites] with the curved part of our wedge and knock his blade up. What we found out from watching the fight videos from Robogames 2012 is that when we hit them with the left wedge it launched him a lot better than if we hit him with the right wedge. The right wedge took a lot of damage and got flung really hard. If we hit him with the left wedge, the other side of his blade would come down and catch the floor. In the future we may be asymmetrical armor-wise and only try to hit him with the left side. But you know, that's not always an option, you kinda just take hits however you can and you only have so much time to get the robot in the right position."

By the end of Combots 2012, Original Sin has amazingly made its way through the loser's bracket to fight a rematch against Last Rites. But Gin can't quite hold onto the championship he's won so many years in the past. Last Rites pops off Original Sin's tires, crippling the speedy wedge bot's mobility, and claims the Cup.

Gin already plans to make some modifications during the off season. Ninety-nine percent of the hobby belongs to the workshop, after all--and to the pit, which will be there for RoboGames 2013 when Original Sin, Last Rites and Electric Boogaloo inevitably show up for competition. They'll all need the pit. Judging by this year's Combots Cup, they'll each spend three minutes beating the hell out of one another and the rest of the weekend putting everything back together.