Faster, Meaner, Deadlier: The Evolution of “BattleBots”
spectrum.ieee.org
spectrum.ieee.org
The full body spinners struggle to keep spinning, as the forces of impact tend to ping-pong them around the arena. As long as their opponent can tank a hit and has a halfway competent driver, the spinners tend to end up corralled in a corner.
The latest season has an absolutely incredible match between Gigabyte and Hypershock.
I think my favorite example of the problems with class full-body spinners was in 2018 when an opponent managed to rip Gigabyte's outer shell off in one piece.
Consider what ziggo (https://www.youtube.com/watch?v=OuyG3FmixRI) could do as a lightweight. Now make it 100kg with tungsten teeth instead of steel and two counter-rotating hemispheres to cancel out the torque and let it turn on a dime. Put gear teeth on the inside of the shell and run multiple drive motors so that you can rev it up to full speed within the first few seconds of the match and then switch off drive motors as necessary to save power. With a heavyweight bot you have a big weight budget for powerful batteries and motors so I think you could fit several kilowatts of power for both the drive system and the wheels, which are important for a spinner since you need quick acceleration to outmaneuver your opponent and attack its weakest point. To protect from getting flipped, you could design the tooth lowest to the ground to be on a horizontal hinge with a linear actuator running through a hole in the shell, so that during the match you can lower it to the necessary angle to hit anything trying to slip underneath.
Napkin math: A 25kg shell, 1 meter diameter, spinning at 1000 rpm has about 17 kJ of rotational kinetic energy, (roughly equivalent to a .50 BMG bullet) so several kilowatts of power for a few seconds should be enough to rev up fully if friction is kept sufficiently low.
Now, when that hits its spinning counterpart, that spinner doesn’t only dump kinetic energy into its opponent; it also dumps it into itself, potentially more so if the enemy is heavier, so on an empty battlefield, the sturdier engine will (on average) win.
On a battlefield with hazards, the better maneuverability should tilt the favor more into the direction of the non- or slow-spinning version. It has more control over where and when the hits take place, so it can (statistically) push its opponent towards hazards.
I think the best strategy for the fast spinner would be to try and stay working, as the jury might give it a points victory on aggression.
What was a design choice the team believed was solid, only to prove a weakness in the Battle Box?
How are these bots tested outside the arena? Do the equivalent of “friendlies” exist?
In our case it was really a death by a thousand cuts rather than any one match. Our bot was a heavy defensive wedge coupled with a thick vertical spinner. That may sound like the meta today, but back then the edge in the meta was still solidly in the realm of heavy horizontal spinners like Tombstone, and our design sacrificed offensive capability for the ability to tank massive horizontal blows to the wedge and spinner. It worked very well, we KO'd Son of Whyachi and destroyed Gigabyte's weapon with this strategy. But taking these blows on the chin over and over and over just rattled the bot apart over the tournament. Before our final match we realized there was nothing to it, we had to tear the bot down entirely and reassemble it with the freshest parts we could find. This was a nightmare; the bots aren't that complicated internally, but because of size and weight constraints and for the sake of survivability everything is very compact, interlocked, and secured. It was optimized for fighting, not easy maintainability, and that's what killed us. We were almost burnt out by this point and getting the bot back together again very nearly finished us off. Several times we put the bot together, then tested it, then something wouldn't work, so then we have to diagnose and tear the bot apart again and put it back together again, and then something else wouldn't work, and it goes round and round and round. Our team captain actually gave into despair at one point and wandered off in a fugue; our welder told us to keep working on the bot until she could manage to snap him out of it. We missed our match deadline, which is potentially grounds for disqualification, but we were lucky in that they had room the schedule to push us back by an hour or so. We finally managed to get everything working with mere moments to spare, but remember how I mentioned that our wedge had been tanking hits nonstop till this point? Well, while our wedge was hardened steel, our frame was just (thick) aluminum. More than 20 bolts held the wedge onto the frame, but all the bolt holes had suffered so much trauma from distributing the repeated impacts that in truth the wedge was barely hanging on by this point. With all the other things we had to do, there just wasn't time to manufacture a new frame or find a way to bore and tap new holes. Instead we found some metal inserts designed to let you "re-tap" holes that had been stripped out (I forget what they're called). But our final match was a three-way against two other vertical spinners, and in the opening moments End Game caught us under the chin at full spinup and absolutely blasted our wedge into the stratosphere, obliterating part of the ceiling rig and several lights in the process. It might as well have been held on with bubblegum. We weren't even mad, it was amazing carnage and we were howling with laughter at our now-headless robot.
> What was a design choice the team believed was solid, only to prove a weakness in the Battle Box?
A weakness of vertical spinners (as opposed to vertical drums) is that they're not invertible, so getting flipped can mean game over if you're not ready for it. Our bot was designed so that if we got flipped, our wheels would still have contact so we could ram a wall in an attempt to self-right. Which worked (in both testing and in-match), but while flipped the front of the bot was riding on the weapon itself, and we were concerned about damaging it. So after we arrived at the filming we machined two little aluminum "rabbit ears" and topped them with slippery plastic, which also increased the height of the wedge's lip when inverted thereby making it easier to self-right by ramming. But this was our undoing. In our fight against Gigabyte we successfully destroyed their horizontal spinner, but in the process they rode up our wedge and snapped off exactly one of our rabbit ears. We should have won that match, but then somehow we wound up inverted and the remaining rabbit ear made us asymmetric and caused us to tip to one side, meaning that one wheel didn't have traction, so we were stuck. Heartbreaking.
> How are these bots tested outside the arena? Do the equivalent of “friendlies” exist?
Teams will do their best to test, but these bots are so expensive (relative to our funding, anyway, which is essentially nil) and so labor-intensive to manufacture and assemble that only the most dedicated teams can afford real testing against other bots. For our bot we did organize an impromptu street fight outside of a bar in Boston (there are plenty of teams in the area to scrimmage with, and obviously for the safety of the public all the primary weapons were disabled). Then after we arrived in LA and unpacked the bot we ran it around an empty Target parking lot to make sure the drive wasn't damaged in shipping. For actual testing at the venue, they provide miniature versions of the arena for you to drive your bot around with the weapon working in a safe environment.
I know exactly which bot you're talking about, it's actually one that I remember pretty well from that season! That three-way rumble was wild, although to be honest it was overshadowed by the one right after where Duck!s win was tragically stolen.
Make a Twitch channel, get a few contestants and set a date for the first event!
It is strange BBC 2 used to have the early evening inventor slot, it used to be The Great Egg Race, then several years later it was Robot Wars.
https://en.wikipedia.org/wiki/The_Great_Egg_Race
Seemingly more like The Great British Bake Off of invention.
Make every single arena a completely flat space where wheels are optimal and then given extra points to sub-optimal builds seems like it would be a poor way to approach things. It would be like giving extra points for creating an aquatic robot, but failing to create an arena with any water in it.
You may also find Snake interesting(https://battlebots.fandom.com/wiki/Snake).
Japanese wrestling robots https://youtu.be/-llRPCwIESQ
No limits - explosives, flames, chemical attack, projectiles. Total destruction!
Viewed remotely for safety - armored cameras and drone shots, displayed on big screens!
But never mind us. Do we imagine there isn't a market for battle robot shows with grenades and machine guns?
Do it in an arena, and there you are: a hit show. Put cameras on all the bots so we can get into the action.
{edit: arena}
Or whoever nudges asteroids to collide with Earth such that the crust melts evenly.
But an uneven floor would likely cause mayhem for the massive amount of centrifical force these spinner bots have. Some bots might be able to handle it, but many would not.
Edit: that’s a great point about the uneven flooring though! Would you expect bots to land belly up or their weapon-plane thrown off?
(The line about Newton's laws in a rotating frame is, of course, entirely true.)
I still used the wrong term though. I was actually referring to gyroscopic motion.
> But an uneven floor would likely cause mayhem for the massive amount of centrifical force these spinner bots have. Some bots might be able to handle it, but many would not.
Sounds like a good thing to me. Introduces constraints and tradeoffs.
Early on people had all kinds of ideas...saw blades, flames, hammers, etc. Then a tiny wedge car showed up and just flipped them over.
Then people put something akin to a lawnmower blade on the front, near ground level, and sent those wedges flying. Another had nothing more than a small blade that rode on the ground, and on command, shot it up at a speed that would send anything on top of it twirling in the sky.
I don't think we should ban any one type. It's just incentive for people to do better.
The producers designed the rules for a show that they hope will deliver explosive action, relative to other tradeoffs.