Norwalk Havoc Robot League, February 2021: The Culmination of All of My Worst Nightmares

When we left off the previous episode, I’d just gotten the new attachments cut by Big Blue Saw and gotten them back. So with but a week to go until the competition, it was time to put all these pieces together and prepare the bot!

These pieces were cut from the same Hardox 450 (HX450) stock that I’ve had Overhaul bits made from since 2018. Basically, it turns out Kloeckner Metals, through whom I had Overhaul weldments-to-be cut out, does NOT reuse partially cut material.

If you buy one custom-cut part, you basically bought the whole plate. As a result, I asked them to slice everything else up into 12×24 rectangles so I can chew on them for years to come. The 4mm thickness in particular has seen application across a few 30Haul changes and even Roll Cake.

The nice thing about genuine grass-fed, wild-caught SSAB Hardox steel is that it’s very uniform in thickness and has a coating applied to it that grinds and sands off very easily to reveal clean metal. So much AR-grade steel is naturally bowed and comes covered in tough (abrasion-resistant, almost…) mill scale.

Above, I’ve already cleaned the pieces with a flappy wheel and have made initial tack welds to hold the shape together.

I did all of this with good ol’ Limewelder, which I discovered recently actually kicks some ass on 240 volts, so much that I’m going to get 0.035 wire accessories for it. I started off with 0.030 because of the need to do light sheet metal work on Vantruck, but on 240 volts it becomes the bottleneck for how much steel I can lay down. There’s some exciting Limewelder work to come yet.

More metal being smeared upon itself here. I generally decline to call myself a welder, as being a welder implies you’re well trained and practiced in the art and science. I prefer to say I host exciting meet and greets for metals.

The parts were joined at the tab-slot interfaces first to lock them in place, I suppose being a pseudo plug weld. Large fillet edges were done last and in a few stages to discourage warping. In this 4mm material, I can pretty much just turn Limewelder up all the way and draw lines – it barely has enough power to just make large stringer beads in this thickness, fillet welding in one pass. Any thicker and I’ve had to bust out my unsteady random-walk weaving, making everything worse.

You know what they say, a painter’s welding is a grinder I ate…. …..or something like that. The completed assemblies were primed and then painted in my favorite generic black robot spraypaint, Harbor Freight Spray-On Bedliner. I can’t imagine anyone actually using that stuff for a truck bed, but it does make a nice matte and lightly textured surface on robot parts that seems a bit more durable than the usual Rust-a-Color.

Hey, remember the “Open Loop Aluminum Donut”? Well, to my utter amazement, all seven holes of the bolt pattern went in without any encouragement. While I’m disappointed at not fitting digital scales to the Benchmaster, Master of Benches yet, I’m also happy to know I can always fall back on “well fuck that” machining techniques.

When all is said and done, here’s 30Haul set up in “generic” mode for Norwalk Havoc. I figure I’d change modules depending on who I was fighting first. The crash kit comprises a labeled spare hardware sorty-bin and a tote full of “Probably Most of Another 30Haul”.

This might be the first appearance of Overhaul 3 on this website, in real life. Because I basically stopped updating as WordPress died more and more, then picked up afterwards with moving and vans as I skipped BattleBots 2020, the entire design and build sequence of Overhaul 3 has been skipped. This is probably my biggest and most menacingly lurking back-blog that I have to do, and I already have the framework for it set up, but just have not mustered the willpower to begin writing yet.

The almost 1 to 1 relation between this 30haul’s geometry and that of Overhaul 3 can be pretty well seen here. No wonder I’m trying so hard to robot again, eh?

While I take forever to get to the write-up, you can see Overhaul get beaten by Sadbot over and over.

We now teleport a day ahead to somewhere in the dank industrial crotch of Norwalk, Connecticut. 30Haul’s been checked in and through the inspection and functional test now, so I get to walk around and check out the BRAND! NEW! NHRL building.

It basically expanded across the street from 50 Day which has hosted the insect-weight events. This is a brand new 30lber-rated cage, of a rather hybrid construction. It’s significantly sturdier than the NERC Motorama box, but is still made of wood for most of the floor sections.

NHRL’s thing is having a giant, slow house bot in the arena (which I support the concept thereof very fiercely), and I also identify with the general “there are no rules” interpretation of rules, especially as it pertains to multibots. In other words, this is not a place for the overly competitive to get uppity about following proper tournament procedures and fair judging. This is a quintessential #PostmodernRobotics experience.

A whole lot of gear and prep has gone into this facility – here’s a photo of the streaming battlestation.

So how did the robot do?

Horrible. Absolutely terrible by record, but I learned everything I set out to learn which, as I looked forward to this event as a shameless buffet bar sample for Overhaul, means I won without winning anything.

There’s not a split-up-by-match video available of the February NHRL, but there is a single stream capture that’s TWELVE HOURS LONG. I can’t actually be bothered to go through it to find the segments of video featuring 30Haul (entered as “This robot is not Overhaul”), so let’s get down to the details.

My first match was against Big Ripto of Motorama fame. Because _of course_ it was. I had no particular strategy going into this one, as it was more to figure one out. I’ve seen enough people do the keep-away dance with vertical spinners, and Overhaul 2’s “Wedges of Limited Liability” were made in 2018 as a way to decrease the attack surface against the likes of Witch Doctor and Warhawk (to varying degrees of success). But the 4 wheel drive vertical disc approach really came into vogue in the 2019 and 2020 seasons, which Overhaul had to sit out. Everything’s gotta be a Bite Force now, huh. In general, that time period was also when I was the most out of the sport as well, so I haven’t really had any actual match driving in over a year.

In all regards, this match went “fairly well” solely because Big Ripto suffered some mechanical and electrical problems. Kyle had issues with the belt drive on the disc becoming entangled, and it also melted a few wires. After the first few collisions, 30Haul had trouble driving much – because the Vex wheels had basically come apart and become little paddles.

On top of that, one of the good hits Ripto got on me actually managed to blow off the entire header on the 6-FET Brushless Rage. Why? It was the only one I somehow forgot to put the double sided mounting tape between the signal and power boards. The others were fine. This was, of course, on one of the drive sides, so between “flappy paddles” and dragging the left side, the rest of the match was a lot of Powerful Hugging.

The “Big Hit” pushed in the rear frame rail quite substantially, and this force transferred through the battery mounting bracket into the motor controller enclosures.

I was able to replace the closely-shaved Brushless Rage and flatten the frame rail enough for the top and bottom plates to fit back on. I learned next that 30Haul’s Losers Bracket match was going to be against Rum Ham, an undercutter kind of design. It’s a heavy hitter, but has historically been a little unreliable on the weapon. Nevertheless, it was a good chance to really test my assumptions when it comes to “T-rex Mode”.

So I began converting 30Haul over to T-Rex Mode. In real life (and for Overhaul) I would have this assembly pre-built and ready to be swapped in, or Bot 2 configured for it as soon as we know the first rounds of matchups. Just like Overhaul 3, the top half of the bot pulls off for independent service.

For the bottom half, I added the Snout using all of the available rubber bumper holes.

And the two halves go back together.

Well, it turns out 30Haul was about 11 ounces overweight in this configuration. I had to remove the (heavier than expected) Vex wheels on the outside, leaving just the chariot spokes. While we’d generally let even 3 or 4 ounces slide at most events, I personally felt almost a full pound over was just too egregious.

I was pretty happy with 30Haul’s durability this match, as I was able to keep the snout pointed at Rum Ham and cause it to destabilize a few times. I went for full speed connections as well – in a match with higher stakes, I’d be more likely to keep on the opponent, whereas I waited several times for Rum Ham to spin back up. Again, just seeing what goes wrong where so I can more effectively address it for Overhaul

I wasn’t able to leverage the situation, however, because one of the hits caught the very tip of the wedge and bent it forwards, which hampered 30Haul’s mobility a whole lot. It wasn’t _not_ driving, but was certainly not able to effectively maneuver.

In retrospect, a bottom brace/truss plate would have been more helpful than internal webs, and that’s one of the mods I intend to make right away to this design. I was otherwise very happy with the physics and the “rise through” functionality of the bottom forks. You can see that one of my “worst case mistakes” did occur, where Rum Ham caught the very side of the wedge and popped off a few of the rubber mounts on the corner.

Alas, due to my inability to follow through with the face-bouncing I did with Rum Ham, 30Haul was declared the loser of that round. I put it back together in “Sportsman Mode” for the 30lber rumble that never happened because the event had been running almost 14 hours at that point.

The next Norwalk Havoc with 30lbers is in May. So what’s the big plan?

I’m revising the Snout design to be stiffer on the corners, trading the internal webs for a U-shaped bottom truss shape. The metal is rigid enough on this scale that I don’t think the center webs contributed much.

Next up, after watching enough Battlebots and seeing enough matches at this point, I’m going to make 30Haul an entry in the “fork wars” currently ravaging the combat robot landscape. The joke is that ground-scraping forks grew a foot over the course of the 2020 season, as one of the only ways to ensure a vertical spinner doesn’t get under you, is to get under it first. Keeping the opponent away and under control is just as essential as being able to take (or deliver) the hit. There’s some amount of rumbling that BattleBots might restrict the “ground game” as it’s called, but we’ll see how that shakes out.

I’m also beginning to like the Vex wheels less and less, because while they initially offered the bouncy compliance I was looking for, once they start disintegrating, they become more liabilities. The spokes will tear through, leaving the big gaps in the perimeter that then flap in the wind. I decided to try and find some thick foam rubber I can use to make at-scale foamy wheels, not dissimilar to Overhaul’s.

All this and more in the next robot updates! Maybe when someone splits up the February stream capture I’ll link to individual videos.

Leave a Reply

Your email address will not be published. Required fields are marked *