Steel For Your Fighting Robot

July 23, 2023 by Jenny List 8 Comments

The job of processing video after a large event must be a thankless one for whichever volunteer upon whose shoulders it falls, and thus it’s not unusual for talks at larger events to end up online much later than the event itself. Electromagnetic Field 2022 was last year, but they have continued to drop new videos. Among the latest batch is one from [Jennifer Herchenroeder], in which she discusses the steel used in her team’s BattleBot, Hijinx (Edit: her EMF talk was cut short due to time pressures, so she re-recorded it in full after the event and we’ve replaced the link. The EMF video meanwhile is here). The result is a fascinating introduction to the metallurgy of iron and steel, and is well worth a watch.

To fully understand the selection of armor steel it’s necessary to start from first principles with iron, to look at its various allotropes, and understand something of how those allotropes form and mix in the steel making and metalworking processes. We’re treated to a full description of the various tempering and hardening processes, before a panel-by-panel rundown of the various steels used by Hijinx.

For a Hackaday writer with a past in robot combat it’s fascinating to see how the design of robots has evolved over the decades since the British Robot Wars, and it’s particularly nice to see the current generation as part of our community. However, if you’ve tempted yourself, bear in mind that it’s not all plain sailing.

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An image of Kitten Mittens and its 3lb counterpart

Why Make A Combat Robot That Walks?

October 1, 2021 by Jim Heaney 13 Comments

If you watch it on TV or see clips on YouTube, you’ll notice that most combat robots have wheels, which would make sense. They are simple, work well, and if designed right they can take a bit of a beating. So why did [Luke] design his 12-pound bot with no wheels, or any locomotion system for that matter? You can find out more about this peculiar bot in his build report with more than 130 images.

[Luke’s] bot, called Kitten Mittens, is a gyro walker combat robot. This means that instead of traditional tank treads or wheels to move about, [Luke] navigates by angling his bot’s weapon and using the angular momentum to lift up one side of the bot to “walk” forward. Watch the video after the break to see it in action. While this does leave Kitten Mittens much slower and less agile than competitors, it gives one massive leg up; weight. Kitten Mittens fights in the 12-pound combat robotics weight class, but most leagues have weight bonuses for bots that have no wheels or use otherwise nontraditional locomotion. Where [Luke] competes, the Norwalk Havoc Robot League, this means that his bot can be up to 6 pounds heavier than the other competitors!

A 3D-printed prototype of Kitten Mittens' weapon — A printed prototype of the weapon, showing off the integrated hub motor.

So how did [Luke] take advantage of that extra 6 pounds? The biggest thing was the weapon. It is made of 3/4-inch S7 tool steel and has a custom hub motor integrated into the center, bringing its rotating weight to 5.5 pounds. In addition to thickness, the added weight allowance permitted a larger spinning diameter so that Kitten Mittens could hit opponents before they hit him.

[Luke] is not new to the world of combat robotics, and knew it would take more than just a big weapon to win. Part of the extra weight budget was also used to beef up his armor and internal structure of the bot, so that hits from opponents would just bounce him around the cage harmlessly. This even included custom bent titanium guards surrounding the weapon, to help in self-righting.

When it first debuted in February of 2021, Kitten Mittens was a smashing success! It went 4-0 in the 12lb weight class at NHRL, winning the $1,000 prize and earning its spots in the annual finals, where [Luke] will compete against other finalists from the rest of the season for a chance to win the $12,000 first-place prize.

Bots that walk, shuffle, or crawl are becoming more of a trend lately in all weight classes. Even Overhaul, a 250-pound bot, has been given a new set of feet to shuffle around on. You can read more about this interesting concept here.

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Overhauling A Battle Bot

August 6, 2021 by Mike Szczys No comments

Where do old battle bots go to die? Well the great parts-bin in the ~~sky~~ corner of the workshop, where they await disassembly and use in other projects. But once in a while, if a battle bot is really lucky, they get pulled out again and put back into working order. So is the story [Charles] is telling about Overhaul 1, a hulk of a robot who was last see in fighting shape during the 2015 season of the show.

Having been succeeded by newer designs (Overhaul 2 and Overhaul 3), it’s a surprise to see some work being poured into these old bones. It didn’t escape the parts bin unscathed, having lost it’s wheels to another design called sadbot. What’s in place now are “shuffle drive pods”, a cam-based system that kind of crawls the robot along. They’re fun to watch in action in the video after the break, just make sure to turn your volume way down first. It’s no wonder [Charles] plans to replace them with newly-designed wheel modules.

In the heat of a match these things take a lot of damage, and the frame of Overhaul 1 was still twisted and mangled. A hydraulic tire jack is the tool of choice as the damage was caused externally and needed to be pushed out from the inside. As a testament to how these things are built, any old jack just won’t do and a 20-ton unit was acquired for the purpose. A set of prongs on the front (called pontoons) was also bent inward and required a chain and a come-along to pull them out.

The nice thing about revisiting projects years later is that technology tends to move forward. We can imagine that the design work [Charles] has in progress for a new set of wheel modules is much easier, and the parts (motors, drivers, batteries, etc) of a much higher quality than when first built over half a decade ago. This is the first installment in the overhaul of Overhaul series, which we’ll be keeping an eye on.

Need to sate your appetite for how to build indestructible robots? Check out how the indestructible wheels for the “Copperhead” bot are fabricated!

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Raspberry Pi Zero Takes The Wheel In Miniature Fighting Robot

June 12, 2021 by Tom Nardi 17 Comments

Looking to capitalize on his familiarity with the Raspberry Pi, [Sebastian Zen Tatum] decided to put the diminutive Pi Zero at the heart of his “antweight” fighting robot, $hmoney. While it sounds like there were a few bumps in the road early on, the tuxedoed bot took home awards from the recent Houston Mayhem 2021 competition, proving the year of Linux on the battle bot is truly upon us.

Compared to using traditional hobby-grade RC hardware, [Sebastian] says using the Pi represented a considerable cost savings. With Python and evdev, he was able to take input from a commercial Bluetooth game controller and translate it into commands for the GPIO-connected motor controllers. For younger competitors especially, this more familiar interface can be seen as an advantage over the classic RC transmitter.

A L298N board handles the two N20 gear motors that provide locomotion, while a Tarot TL300G ESC is responsible for spinning up the brushless motor attached to the “bow tie” spinner in the front. Add in a Turnigy 500mAh 3S battery pack, and you’ve got a compact and straightforward electronics package to nestle into the robot’s 3D printed chassis.

In a Reddit thread about $hmoney, [Sebastian] goes over some of the lessons his team has learned from competing with their one pound Linux bot. An overly ambitious armor design cost them big at an event in Oklahoma, but a tweaked chassis ended up making them much more competitive.

There was also a disappointing loss that the team believes was due to somebody in the audience attempting to pair their phone with the bot’s Pi Zero during the heat of battle, knocking out controls and leaving them dead in the water. Hopefully some improved software can patch that vulnerability before their next bout, especially since everyone that reads Hackaday now knows about it…

While battles between these small-scale bots might not have the same fire and fury of the televised matches, they’re an excellent way to get the next generation of hackers and engineers excited about building their own hardware. We wish [Sebastian] and $hmoney the best of luck, and look forward to hearing more of their war stories in the future.

Balloons And Bubbles Make For Kid-Friendly Robot Deathmatch

March 17, 2018 by Dan Maloney 6 Comments

Because nothing says “fun for kids” like barbed wire and hypodermic needles, here’s an interactive real-world game that everyone can enjoy. Think of it as a kinder, gentler version of Robot Wars, where the object of the game is to pop the balloon on the other player’s robot before yours get popped. Sounds simple, but the simple games are often the most engaging, and that sure seems to be the case here.

The current incarnation of “Bubble Blast” stems from a project [Niklas Roy] undertook for a festival in Tunisia in 2017. That first version used heavily hacked toy RC cars controlled with arcade joysticks. It was a big hit with the crowd, so [Niklas] built a second version for another festival, and incorporated lessons learned from version 1.0. The new robots are built from scratch from 3D-printed parts. Two motors drive each bot, with remote control provided by a 433-MHz transceiver module. The UI was greatly improved with big trackballs, also scratch built. The game field was expanded and extra obstacles were added, including a barbed wire border as a hazard to the festooned bots. And just for fun, [Niklas] added a bubble machine, also built from scratch.

The game looks like a ton of fun, and seems like one of those things you’ve got to shoo the adults away from so the kids can enjoy it too. But if you need more gore from your robot deathmatch than a limp balloon, here’s a tabletop robot war that’s sure to please.

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Paydar: What It Was Like To Battle Bots In 2002

February 27, 2016 by Gerrit Coetzee 34 Comments

Most people remember when Battle Bots was a big thing, but few of us got to live it as seen in this gallery. Every now and then, someone posts something more amazing than usual in the comments. When [Wolf] was studying at IUPUI they somehow convinced a professor to let them build a scary dangerous robot maiming device for their final project. It’s a cross-disciplinary project — even the medical students may get to participate.

Spike vs hours and hours of work. — Spike vs. hours and hours of work. Victory: spike.

Their bot, unfortunately, got taken out by some spikes after attempting to get a spinbot before it started spinning and got them. If you look closely at the 2002 Comedy Central Battlebot opening you can see the smoke pour from their robot as they try to escape the fatal spikes.

The robot itself is a three wheeled design. The two wheels across from each other drive the robot, and the third steers. There is a very cool encoder mechanism for the steering wheel that is worth checking out. The main drive motor is a hefty 15HP electric forklift motor current limited to 300amps. The robot never got a weapon thanks to slow mechanical engineers, but a motor like that can turn most chunks of metal into deadly weapons.

Battle Bots is making a comeback in some ways. Word’s still out if it will ever go back to it’s prime, or if something more insane will replace it.