We did it! In a few short months we formed a team, obtained sponsors, built a 60lb robot, and competed at RoboGames 2024 with Torment Nexus! And despite biting off a technically challenging design as our first big bot, we even won a fight!
The event and everything leading up to it was the full roller coaster of emotions. Late nights. Difficult challenges. Last minute assembly and repairs. Learning exactly what worked about our design, and what needed improvement. The joy of seeing the robot spin up fully for the first time. Winning a fight. Proving that our design can work.
Wait, what is a Torment Nexus?
Torment Nexus is a 60lb melty brain, a super cool but famously challenging type of combat robot that spins its entire body around. This means that the full weight of the robot rotates, and impacts its opponents with devastating force.
Melty brains pose unique design challenges, such as being able to translate while spinning, and withstanding the sheer impact force that they are capable of generating.
The robot is named after a Sci Fi meme posted to Twitter about a fictional product that, for the good of humanity, should not be built:
This felt appropriate for a 60lb spinning disc with teeth.
Testing: Torment Nexus vs the Arena
After passing out in bed at 2am way too often in the weeks leading up to RoboGames, we arrived in California with Torment Nexus ready for combat. Sort of…
When you have a spinning robot designed to hit opponents with more force than a 50 calibre round, testing it by letting it loose inside your garage like a drunk Roomba isn’t a good idea. If it hits your garage door, it may just pass right through it, and right on through your neighbour’s as well.
This insanely energetic potential greatly limited the type of testing that we could safely do. The arena crew at RoboGames were sympathetic to our plight, and allowed us to test Torment Nexus before our first actual fight.
For the first time ever the full Torment Nexus, wearing its 27lb shell of destruction, was allowed to spin up. To full RPM.
The test started off great. Sure one motor was spinning the wrong way for some reason (quickly fixed with a VESC setting), but the bot could drive. It could spin. And so we cranked the throttle further. Suddenly smoke went up. And the bot stopped. Spinning up to full speed had caused the tires to detach from the wheel hubs, jam our motors, and actually melt the tires. All in a second.
That wheel don't look right!
Our robot had been defeated in the arena without an opponent! Fortunately we brought lots of spares, and had the opportunity to test our teamwork skills by rapidly replacing the wheel and motor assemblies ahead of our first fight. But clearly there was a critical problem with our wheel design, and how is a melty brain supposed to fight when it can’t spin?
With this terrible news, and no time to do anything about it, we moved on to our first fight…
Fight 1: Torment Nexus vs Come to Mama
Our first fight was against Come to Mama by team RoboMaster.
With the tire incident fresh in our minds, we knew we had to be careful in the fight. We agreed that we would limit our spin rate to only 1,000 RPM. This was tough to do as the throttle controls current to the motors rather than setting a speed. So Matt had to watch the sensor output on the radio and tap Brian's shoulders anytime we crossed our limit.
We started the fight with a spin-up hoping for an early hit, but with us being a melty brain with translational code that still needs refining, and Come to Mama having a drive issue of their own, we just weren't going to make contact this way.
We flipped to ramming mode, and did manage to get closer, while being careful to avoid too much spin and too much translation (which would stress the tires further).
Near the end we managed to get into a good position, risked another spin-up, and landed a solid hit against our opponent. This appeared to have earned us a very narrow win via judges’ decision.
In the post-fight analysis we discovered that we left a nice big gouge on Come to Mama as well as bending up the frame for good measure. Apparently Torment Nexus hits hard even when it’s barely working!
Those AR500 teeth on Torment Nexus can definitely deliver hit! Come to Mama suffered a bent frame and has a pretty new gouge as a souvenir from the fight.
Alas the fight also revealed a second design weakness on a structural component of Torment Nexus. Even though the chassis was fine, the aluminum inner frame rails that hold our motor had actually bent from the single hit. This was an important finding for us, and something we know we can address.
Result of a heavy spinning bot coming to an instant stop. Fact: Isaac Newton was a jerk for inventing inertia.
Fight 2: Torment Nexus vs Tastes Like Burning
Our next fight was against the eventual RoboGames 2024 lightweight champion, Tastes Like Burning, from team Widowmaker. We were super hyped to fight a flamethrower bot (and a little nervous about being cooked), but we expected a good match and to learn a lot.
We went into it with the exact same plan to take it super easy on the throttle, don't spin too much, and hope for the best. The fight started and... the tires popped off. Like immediately. Doh!
Whatever bonding strength existed between the tires and the hubs had apparently been completely weakened in the last fight.
Sigh...
Tastes Like Burning smartly seized the opportunity to grab us and start driving around the arena while torching our bot, which made for some epic photos and a happy audience. Unfortunately we had to tap out quickly, since at this point we had no drive whatsoever and we were being leisurely slow-cooked with a flamethrower.
We hope that we get to rematch this one next year. They were a great team and we owe them a better fight.
Interlude: Wheel Panic (and redemption?)
With our next fight not until the next day, and a desperate desire to put on at least one good show, we jumped on ideas to fix the tire issue in the pits. What followed was incredibly fun, stressful, and bizarre problem solving.
We hotly debated running the hubs with no tires at all. We tried riveting cut up bike tires to the wheels. We tried threading steel wire to hold the urethane tires on.
Kaleigh using her surgical skills to humour our ridiculous ideas...
Unfortunately all ideas proved infeasible in the end, resulting in frankenstein atrocities that had no hope of working. However in the process of trying to solve the problem, we had super glued the tires onto the hubs to hold them better while we worked. And you know what? They kind of seemed to stay on pretty well…
With hardware stores long closed, brains out of ideas, and sleep beckoning, we decided the superglue was all that we could do, and maybe it would be enough?
Fight 3: Torment Nexus vs Herr Gepoünden
The next day it was time for our fight against a different, older and battle tested melty brain design, Herr Gepoünden of team Zwölfpack. Being a melty ourselves we were very excited for this fight, but at this point very unconfident in our wheels.
We started the match not spinning up at all, with plan A being to try ramming our way to victory. That didn’t proven very effective, and to the audience it just looked like two robots drunkenly stumbling into each other. This was not the way we wanted to end our RoboGames 2024 run. So we took a chance and spun the heck up!
The beautiful death roar of Torment Nexus started to fill the arena. We held our breaths waiting for the tires to go flying off in a fit of smoke… but against all odds… the tires stayed on and the bot kept spinning. It was melty time!
Our opponent jumped in on the action and spun up as well, and suddenly two melty brains were attempting to make contact with each other. After a couple grazing glances, we hit! Both bots went flying, with Herr losing one of the linkages that held his hammer straight.
Both still functioning and in it, we went in for another, harder hit and boom! Both bots flew again, but now Torment Nexus was very wobbly and not spinning right. This resulted in Herr herding us into the wall, where we got stuck due to one side of our drive no longer working.
The tires had stuck on the whole way through (thank you superglue!), but just like in our first fight, our hit resulted in our frame rails bending as they fought the inertia of two heavy motors that were very much still wanting to keep moving.
This time the rails bent so badly that it shifted one of our motors out of alignment, causing us to lose drive on that side and ultimately get stuck not being able to drive off the wall.
Even though we lost the match, we were extremely happy with this one because we finally got to demonstrate the CRAZY kinetic potential of Torment Nexus.
That linkage used to be attached and that hammer mount isn't meant to be a banana...
In just two solid hits we had:
- Tore off one of the linkages from Herr's weapon mount
- Completely bent the weapon mount itself.
- Took a big chunk out of Herr's hammer.
- Bent and broke the thick piece of steel that protrudes past Herr's hammer.
- Slashed a wheel for good measure.
Turns out we bent the whole hammer mount, and left another nice souvenir via a gash in the hammer itself.
Clearly there’s (kinetic) potential in our design, and we believe that Torment Nexus will be a force to be reckoned with next time. Or at least put on an epic show!
The absolute best part of combat robotics - you can trash each other's robots and still be friends after!
Next Steps
We would all have loved for Torment Nexus to have debuted as an ultra destructive, and indestructible, bot. Victorious music would play as we flew home to Canada with gold medals around our necks, smug in the brilliance of our engineering work and infallibility... Ha!
In reality building a combat robot is an iterative, collaborative and extremely humbling experience. We are overjoyed with how much of the robot did work, in particular the fundamental pieces that determined whether this design would work at all. And hey, we were actually pretty destructive, it's just that we destroyed ourselves just as much as we destroyed our opponents.
The gyroscope did what it was supposed to. The electronics didn’t crumble. The robot did in fact spin up and show translational movement when we told it to (ok sure… the algorithm needs work, but we know what needs to be tuned). The extremely precious 27lb outer shell did not crack on impact.
Thanks to the incredibly supportive builder community, we already have advice on how to fix the tire issues, including two different leads on how to bond urethane to aluminum reliably.
The arena dust has barely settled and the lipo smoke cleared out, but we march ahead with our goal of building a kinetically entertaining and competitive melty brain that can scale into a BattleBots heavyweight competitor.
Thank You Sponsors!
Thank you SO MUCH to the support of our sponsors for making this possible:
For the last 3 months this project took every single ounce of free time, every single spare dollar (and then more still), and every scrap of sanity to bring it to reality. Without the support of sponsors, and a dedicated team, it's simply not possible to build a robot of this scale, and we are extremely grateful to everyone that made this build possible.
Interested in sponsoring Torment Nexus? Contact matt.inglot@gmail.com and let’s chat about how we can make a Battlebots version of Torment Nexus a reality together.
