Sparks have been flying in the latest BattleBots series of arena duels between heavily-armed fighting robots. In fact, it’s not only sparks but flames, smoke, and chunks of AR500 steel, titanium, and Kevlar. Standing out, literally, is HUGE, a newcomer that towers above its opponents—just as its name suggests. HUGE has won all three of its fights this year.
In BattleBots, remote-controlled robots battle in three-minute bouts, where their goal is to disable or destroy opponents using technology, engineering guile, and sheer, brute force. The weapons of choice include hammers, heavy spinning bars, diamond-edged saws, flamethrowers, support drones, and even projectiles. The weapons are so powerful that 110kg (250lb) bots are flung high into the air by force of impact—and fights often end with bots losing wheels and weapons, clouded in smoke, or occasionally smashed into expensive fragments.
HUGE, a unique, spindly bot that looms over opponents on its big wheels, was designed and built by a five-person team, led by Jonathan Schultz. The team’s members met in college and in bot fighting competitions. Mouser is the team’s sole sponsor.
BattleBots currently airs on both the Discovery Channel and the Science Channel in the United States (US) and has previously been seen on Comedy Central and ABC.
HUGE is a deceptively simple robot design: Essentially, it’s a central axle with an independently driven spoked plastic wheel at each end and a vicious vertically spinning metal bar in the center. The outer ends of the bar whack opposing bots at over 350 kilometers per hour (close to the BattleBots safety-imposed speed limit of 400 kilometers per hour for external moving parts).
The success of HUGE shows how there are many paths to solving engineering challenges and illustrates how it helps to stand back and think about the overall problem rather than focusing immediately on components and diving in with a soldering iron and a wrench. Two of HUGE’s key advantages over competitors seem rather simple: Its overall shape and scale and its designers’ smart choice of materials.
First of all, as its name suggests, the bot is literally huge in comparison to most competitors, so its main axle, electronics, and motors are out of their reach. Only the wheels and the spinning bar weapon can be hit, and opponents are usually trying to avoid the latter. So the relatively thin-spoked wheels are the only direct target for most enemies—and this is where choosing the right materials becomes a factor.
For the wheels, the team’s choice of ultra-high-molecular-weight polyethylene (UHMWPE) is ideal. This is mainly because it has extremely high-impact strength and flexibility. As a result, the wheels tend to bend and absorb the force of hits rather than breaking. Despite being 1 meter high, the wheels only weigh about 8kg each, leaving plenty of the rule-mandated 113kg weight budget for the robot’s 14kg AR400 steel spinner bar weapon, sturdy central axle, and multiple heavy-duty motors.
Of course, while a good design is essential, the real test comes in the arena. “You learn so much from fighting a robot that you can’t learn in any other kind of testing,” says Schultz, the team’s leader.
In a typical battle, opponents land numerous brutal strikes on HUGE’s wheels, but the plastic just flexes, actually pushing HUGE away from danger and then springing back into shape, barely scratched. What about flamethrowers? UHMWPE plastic is vulnerable to softening at temperatures as low as 80°C (175°F), but with the limitations on fuel, flame heat, and combat time that the competition’s rules and safety regulations impose, it’s difficult for opponents to apply damaging heat for long enough. In any case, the wheels seem sturdy enough that the HUGE’s powerful 48V motors should be able to keep the bot moving even if a spoke or rim is broken.
Redundancy is an important part of the design. “It's got four entirely separate electronic systems, each controlling a motor and speaking with the same transmitter independently,” says Schultz. “Therefore, no wires have to go through the shaft, and we theoretically can never experience the entire robot electronically dying in a single hit, as there is no single point that can be destroyed to disable the electronics of the entire robot.”
Team HUGE developed the robot’s basic design two years ago in a lightweight 14kg version, and it performed well in several competitions. They have iterated the design, improved it, and scaled up HUGE to suit BattleBots, which hosts robot battles equivalent to a heavyweight division.
“It took the first couple matches to really believe that the design style of HUGE was viable,” admits Schultz. “It’s pretty common to visualize how upcoming fights will go, but much rarer for things to actually go as planned. A little part of me always expects it to split in half and explode as soon as I spin up the bar.”
The team’s electronics designer, Peter Lombardo, says the initial expectation was that opponents would develop strategies to defeat HUGE’s basic design within six months, but that hasn’t really happened.
“When we heard the show [BattleBots] was coming back, we spent a really long night putting together some simple models and renders just to show off the robot design and show off the projected size of it compared to other previous competitors,” Schultz says. “This design was totally unfinished, so we were just hoping we could deliver on what we promised.”
Despite the rush to make the bot ready, the team was “absolutely overjoyed at how well it worked,” Schultz says. “To win your first ever fight in the BattleBox takes the pressure off for all your next fights, and [it] helped us out moving forward.”
In the US, BattleBots can currently be seen on the Discovery Channel on Friday nights at 8:00 p.m. eastern time (ET) and on the Science Channel on Wednesday nights at 9:00 p.m. ET.
Make your own HUGE papercraft, using the template in Figure 1 and these instructions:
Figure 1: Make your own HUGE papercraft! Just download this template and follow the instructions. (Source: Mouser)
Erik is the Social and Multi-Media Manager at Mouser Electronics. When he’s not tweeting about what’s next in the world of engineering for @MouserElec or uploading videos to YouTube, he can typically be found nose-down in a good Sci-Fi book. You can see what he’s up to on Twitter: @ErikSmith80