Robot Ruckus at Orlando Maker Faire: How to Somewhat Scale-Model Test Your BattleBots

Hello everyone. Here’s a photo of Überclocker 5 experiencing Waffle House for the first time, alongside Earl of Bale Spear team, who makes a better “BIG CHUCK” figure than I ever will.

Let that image never fade from the collective knowledge of mankind.

Anyways, as Robot Ruckus approached, I had to figure out how to get my bots all the way to Florida. Taking a week or so to drive there and back was kind of out of my realm of possibility at the time, so I decided to run a little bit of a relay race with the HUGE team.  They’re in Connecticut , which is either a suburb of New York or Boston depending on who you talk to.

I delivered Sadbot, Clocker, a tote of spare parts, and a toolbox to them one fine Sunday afternoon. They were then going to drive everything – Huge included to Earl in New Jersey (if you recall, Earl also brought Overhaul to Battlebots in 2018!) upon which he will travel to Florida. So after the delivery, I had plenty of time to do Other Stuff before flying down to Orlando.

Upon my arrival, I obviously had to grab a rental car. I figured that I’d get the shittiest econobox possible since I wasn’t going many places, just to the event and a hotel room. Well, when I got the reservation and headed over to the rental car garage, it turns out the company was out of shitty econoboxes.

So what now, do I get a free bicycle instead? Nope. Free upgrade time! The garage handlers throw me a key fob which I assume was to the small dorky crossover nearby.

Nope, behind that:

Thanks, I hate it.

Let me be very clear: I’ve forgotten how to drive. No, not in general, but remember what I’m mentally calibrated and trained to for years: Being high up and on top of the front axle, and having a very short or nonexistent hood.  THIS WAS NEITHER. You cannot see out of these. Not out the sides, not out the back, and barely out the front.  I guess that’s the trade for prioritizing looking cool and edgy. For yours truly, stepping into any modern car requires some zen and meditation, and a constant reminder that I now have a front.

I am always terrified of automatically failing over into “van mode” while driving anything rental, and going full Unintended Acceleration into a store or dumpster or fire hydrant as I try to park 1 foot away from something.

How fast does it go? Greater than Van. I dunno man, I don’t have a good sense for How To Fast. My friends who work at GM (who had to listen to me complain about it in real-time) said it likely has the rental-car spec turbocharged 4-cylinder Ecotec engine, which may explain why I was experience what I swore was turbo lag, but more likely might be several inter-related drive feel variables like any economy modes it was stuck in.

2019 Chevrolet Camaro: Faster than a 1986 Ford Econoline.

 

Also, this interior panel fell off while I was heading back from the event at one point. It snapped back in, of course, but seriously?

The trip from the airport to my hotel was made in complete darkness, in the rain. Great. So I’m sitting 2 inches off the floor behind 8 feet of snout, unable to see anything, trying to figure out why every new car is a forsaken spaceship simulator inside, and mingling with other equally lost tourists trying to figure out their own rental cars on the fly. Through several construction zones, to boot. I guess I’m glad I went ahead and got the full-plausible-deniability add-on.

When I arrived at the event the next morning, I found Uberclocker like this.

 

Aaaaaaaaaaaaaawwwwwwwwwwwww. Earl took it in a South of the Border restaurant apparently, and they had these convenient accessories available.

 

I unloaded totes and began setting the bots and infrastructure up for safety inspections.

Sadbot

Sadbot was up first against the multibot Crash and Burn, built by Fingertech Robotics (incidentally, a Ragebridge dealer!) and which has done very well at Robogames events. They were running in kind of a reduced functionality state for this event, so it was more or less a pushing match. Sadbot is obviously a great shape to get pushed around, so it went about as expected with the exception of me getting a few good shoves in. At one point, I took a huge gouge out of the railroad tie side bumpers with the log splitter tip. It definitely did its job.

In the first 30 seconds of the match, the lifter controller popped. Uh oh!

 

It was a pre-production 12-FET brushless Rage board that I pulled out of a bucket labeled “SAD RAGEBRIDGES” and wired up. I probably deserved this.

It would appear I neglected to solder some of the pins on the MOSFET packge. Quality control! That probably popped as soon as it saw any heavy load. I replaced it with a “production model” I brought along in the pile of Equals Zero wares.

What’s more important, though, was the powertrain holding up great for that entire match of me running around and into things. The C80/100 drive motors were lukewarm, and so was the aluminum heat spreader plate in the electronics deck. And even better? I loved driving the damn thing. I mean, saying it handled like Overhaul 1 would be cheeky. Obviously from the video, I took a while to get re-engaged with bot dynamics. But afterwards, it felt like driving a big 30lber, which is my desired effect. Big wheels and conservative gearing seems to be holding up so far.

Sadbot’s next match wasn’t going to be until Sunday at this point, so I decided to take the opportunity to go to Home Depot and grab some….

…masking tape, a big wire brush, and some spraypaint.

This thing has always needed a paint job, and I wanted to paint the frame pastel purple to match the Miku blue and pink attachment aesthetics. Well what better time than now? It was a bright and only somewhat windy day outside and around 70-something degrees. I brushed off the accumulated rust and grunge on the outside and had at it. Paint+Primer, you say? I dare you.

So there you have it. Sadbot will be purple from now on.

My next match was against the other multibot, Macaroni and Cheese. The matchups are “DETERMINED RANDOMLY”, or so I am told. Maybe the random quantum computer just really likes seeing multibots get thrown around.

I went a little more hard-headed in this match with the added confidence of the previous fight, more actively chasing as well as trying to back off from engagements. I stayed to a “I weigh more than thee” strategy instead of trying to capture with the pokey dingle, and managed to drive both halves in the wall a good few times, including propping them both up by the end.

One of these power charges had the unfortunate side effect of making Sadbot somewhat droopy.

Ah well. This match was a much more aggressive one from the stick perspective. I purposefully drove like the maniac I should be driving like, to see if I could get anything to upset itself. The motors got warmer, but not concerningly warm, and I unfortunately neglected to take a controller temperature.

I asked Earl to use Farmer Force™ to straighten out the pokey dingle a little – the upside of it being slightly bent was it at least touched the floor.

 

Sadbot’s final matchup was against Kraken, the actual BattleBots entry. This was finally a chance to drive a match against an opponent of equal weight, and what an intense driving match it was – I went full hard as if it the Giant Nut depended on it. This thing also perfectly fit in Kraken’s trap, as I found out. I kept the pokey dingle at a height to engage Kraken “in the jaws”, and did it once and drove it into the corner. However, once we recovered, Kraken got a better bite on the lid, which led to…

Oops. That’s the outrunner’s wires getting squashed into the rotor. One of the downsides of using external rotor’d motors is you have to pay a lot of attention to where your wires are going. It would have been better to make this a side-exit mounting instead of top-exit. Overhaul, if I keep this drive setup, will definitely have an external shield over the rotor to prevent this.

The wires took a little while to get chewed through, during which it was shooting sparks out the side of the bot which I thought was the controller exploding. I lost this side of drive around 75% of the way through the match, so had to play defense and pivot to keep facing Kraken. Anyhow, I couldn’t find any explosion signs on that Brushless Rage, but I also didn’t feel like repairing this at the event after the Heavyweight bracket ran out of time – originally, each bot was supposed to get 4 matchups, but only we had three in the end. This will be a forensic investigation for later!

Überclocker

Clocker got off to a …. great? Memeful? start by fighting “Marty”.

I’m going to let the video explain itself. Well, I found out it’s definitely front heavy, but it’s also compounded by the fact that Marty is enormous. I also found out this match that Clocker gets stuck on the floors very easily here – they’re plate steel laid on wood foundation, and definitely were shifting around as the event wore on. That’s one of the foils to having a super low wedge in BattleBots – the arena floor will only get shittier, and you’ll definitely regret missing your charges. It’s a tradeoff – possibly get stuck or bounce off a seam, but have weight on the ground.

After I parked the bot at the end of the match, I noticed when picking it up that the lifter was actually seized. What on earth?

It would seem that I #HardParked it maybe a little too much, and the P61 bent in half.

Uh oh. This is maybe an engineering oversight, but the failure mode is also a little infuriating. See, the P6x series shafts neck down to 10mm no matter what diameter you order them as, to pass through the bearings which are of limited size to support the mounting hole pattern. They’re also made of stainless steel.

 

This last part I don’t really get, but basically the shafts are rather soft. So once the preload on the screws is overcome, the whole thing will buckle. Maybe I should have secured them with a 2nd plane or backup plate of some sort. Or maybe I should have used a face-mount technique instead so there’s no “gear climbing” force. Or maybe…

Okay, whatever. I didn’t need the full torque that the 45:1 ratio was going to give – I more did it for a limited lifter speed, but I suppose that’s why I took the care of engineering clutches into Overhaul, and Clockers Past, so it didn’t consume itself.

That’s why you might have noticed the bot split in two for service during Sadbot’s segment. I managed to get a P60 from another team that was the 16:1, two stage ratio, so I had to fiddle it into the bot. This involved cutting the height spacer down in length because the mounting pattern changed. Luckily, I anticipated something dumb like this happening, and the bottom rail has both the 2:1 and 3:1 pattern.

The only downside of going 16:1 is the lifter will be almost hammer-speed. But this could be entertaining in its own right!

Clocker’s next fight was against Ascend, a very powerful 30lb pneumatic flipper. This was going to be a durability test!

It was hard to get under using conventional means, so I mostly had to drive around it and hope to catch it vulnerable post-flip. I also spent an infuriating amount of time trying to get out of a floor seam.  Clocker went flying several times in the fight, which was the shakedown test I wanted.

Near the end, it got stuck upside down because the retaining bolt for the lift axle on the left (gear) side actually backed out and fell out somewhere!  So the gear just skipped as I tried to put it back upright. I managed to get one good grab-and-lift and a couple of other pushes, but didn’t prevail in the decision.

What was cool was I actually got a wheel nibbled off from a direct flipper shot in the first 30 seconds, then drove the entire rest of the match on 3 wheels. Just fine.

This was very exciting. To me, this means if I can keep the chain and inner hubs on, I can treat the wheels very disposably. Not that I’d do it as an explicit tactic, but as get out of jail cards if the situation forced it.

In Overhaul, I’d likely keep the inner wheel tightly retained while the outers are left to float on plastic/shear-rated hardware. I have a few ideas of how to do this for Clocker itself come Motorama.

Another downside of just coupling your actuator to the bot lazily: When your actuator suddenly has 3 times the power, it’s gonna start consuming itself! Remember I put a 42mm brushless on the leadscrew drive instead of the usual 500-class drill motor.  Overhaul has a dedicated trunnion on the lift hub, this is just me not wanting to bother redesigning everything after the lift gear to use a 30lb-scaled one.

The lift motor didn’t blow itself up this time, and in a way I found the lessened torque to be more tolerable. I still clearly had grab and lift ability, but now with the weight of the bot having more leverage against the motor, I noticed I could “trim” the bot better in that match. I’d stick-down just a bit, and gradually the thing finds its self-levelling point. I could then periodically stick-down to refresh it, in a way.

All patched up after wheel service.

Clocker’s 3rd and last fight was against BEEESS???!! (You must only say its name with the upward questioning inflection). I found it hard to get a grab on with his defensive tines sticking out everywhere, so this match was just a lot of driving practice.

And that’s it. Sadbot came away 1/2, and Clocker ended up 2/1! After the event was packed up, I sent the bots back up north with Earl and picked them up from Connecticut again the week after.

Well, not before getting up to some shenanigans in the dark behind the building.

Sadbot, being “Extremely robot shaped” as we termed it, was used as a test dummy by a few teams with lifters/grabbers. Here is a future possible BattleBots entry, Claw Viper, tuning lift motor settings using Sadbot as a dead weight.

The Real Giant Nut was the Lessons We Learned Along The Way

So I’ll do a  more in-depth discussion of the implications for Overhaul separately as its own design series. But here were my two biggest takeaways from this event:

  • If I can make the equation “Overhaul 3 drives like Sadbot drives like Overhaul 1” work, then I feel far more confident bringing sexy back in the arena. I’m satisfied with this powertrain setup, consisting of the single 80mm brushless motor on a Brushless Rage, geared conservatively for about 13mph, and back riding on big blobby wheels.  What I’d probably do is use this as an initial design path, but have a failover ESC solution (VESC controllers have grown up a lot in the past 2 years) as well as a failover brush DC solution. I have some candidates in mind for the latter which I tested over these few months and think are a good idea. More on that later!
  • Clocker was a great architectural test beyond what I intended to accomplish. I definitely wasn’t counting on losing a wheel here! The bot was vastly easier to maintain, even replacing the lift gearbox with a different ratio. I now know that the frame should get longer to better grab and lift – part of the issues stemmed from having to move the front wheels so far back. The small poker wedge legs worked out reasonably, but I’d probably want to make several kinds because of the arena floor. There’s only minor changes and mods I want to make before Motorama. For one, it needs to test the DETHPLOW architecture for Overhaul, and maybe implement my 2-stage breakaway wheels.

One thing to note about Clocker is that I should have dropped the Angerbox clamp drive system to a single stage. I’ve basically done away with the requirement that either Clocker or Overhaul can crush stuff. The clamp should therefore be fast to close, something it wasn’t really at this event. Clocker and Overhaul will likely run single-stage gearing into their clamps for future events.

Between these two major differential tests, I think I have a good handle on what Overhaul 3 has to be.

Namely, it should be Sadbot, but with a grabber and lif….. wait a minute. #holup I swear I’ve built this bot before.

 

Überclocker 5: Finishing Up The Everything Else

Last episode, I had just finished machining and assembling the frame. As I said then, it felt a little wrong. Almost too simple compared to my usual. Well given that’s one of the major directives of this build, and for Overhaul 3, I’d better get used to the feeling. So with the aluminum machining taken care of, it was time to do some welding and final assembly.

The new leg design is almost 1 for 1 what I want to build for Overhaul. Its armored pontoons were a good idea for some forms of kinetic energy weapon dispersal, but weren’t very good at wedging otherwise. Last season I made the “stiletto” versions for matches where having broad surfaces against the ground would be a liability, but the way it mounted to the bot was still predicated by the angled wubbies. I could adjust their ‘preload’ into the floor with washers, but this was permanent (for the match duration) and they actually would impede the bot’s motion by slightly lifting the front small wheels off the ground. There’s really no substitute for a good set of hinged wedges that will always conform to the floor under gravity. I’d eventually want to redo these plates from an alloy steel like Hardox or good ol’ AR400, but for now, a surplus piece of on-hand 1/8″ cold roll steel works too.

Initial tack welds were laid down the parts as-fixtured, then I’d remove the leg itself and add a dab more weld bead. The design was specified for approximately 4mm gauge AR steel, but using 1/8″ cold roll meant there was a lot of placement slop, so I’d rather fixture as the parts were going to be used.

Top side in progress, mostly done.

And then backfilled from the underside. I then ground all four undersides smooth, and painted over the legs and mounts in black.

While the various painted parts are all drying, onto assembly work.  There’s a series of little spacers that have to be installed for the wheels to attach at the right distance to clear the drive chains. Not the most elegant approach, perhaps, but one that was workable given the commercial nature of the parts. For Overhaul I’d have custom hubs with the correct spacing already designed in.

On the inside, a series of washers to hold the hub face on. Another slight point of tack is to put the wheels on, you really need to remove the outer “hubcap” plastic Versahub because otherwise there’s no easy way to line everything up looking through the 1/2″ hex bore. A minor complaint, and really I could just put a plastic circle piece here instead of the Versahub.

Well, it has wheels now!

The lifter motor is suspended off the lower plate by a large gearbox-shaped spacer. It’s a bit of an overconstraint with a fixed bearing in the frame rail; same with the external bearings on the drive motors. Overhaul will have these be isolated systems with flexible couplings like I have on the existing lifter design.

 

The lifter fork and clamp parts all slide onto the main shaft one by one. The dead shaft does allow this thing to be far more serviceable than Clockers Past.

Once the three crossing tie rods and spacers are tightened, the assembly is rock solid. Unlike Clockers Past, the only method of force transmission  from the lift gear side to the “drive” side (right hand) is through those three interspersed tie rods. With the live drive shaft, both forks directly received motor torque. Now, My Calculations Show™ that the rigidity is adequate even picking up a 30lb opponent entirely on the right fork.

Overhaul already has a method of through-transmitting lift motor torque in the form of the big hollow hub the arms sit on, so the considerations there are much different.

Support legs all installed and tightened. A shoulder screw whose shoulder is the length between the hinge sides gets tightened down, and that’s all.

As I expected, this thing is really front heavy. The CAD model doesn’t quiet show it all, even, because it’s a static representation. With nothing in the back, the bot tips forward on its two front wheels immediately.

There will be things in the back, of course, and the final design showed I could possibly have a 3 pound counterweight spanning the back frame rail.  We’ll see how it ends up. I also suspected that the bot will drive very differently depending on how squished the front wheels are (i.e. how much downforce is placed on the arms).

One minor “oh yeah, I modeled that” as I mounted the drive chains: I specified flat-head screws for most of these frame connections, but to do waterjet layout when I wasn’t the one using the machine, I had to make a configuration of each part with the countersink diameters suppressed.

Then I promptly forgot I was supposed to use flathead screws, so installed button heads. This works fine for every place that doesn’t have a chain run next to it, of course, so I didn’t even notice until now.

Ah, that’s much better.

Electronics installation goes quickly, but first, I needed to throw things inside to get wire run distances.

Another “PM Charles” habit I learned and now don’t feel right without: I even created a wiring diagram for this thing with gauges, connections, and lengths before I cut a single piece of sumptuous silicone-insulated ultra-flexible noodle wire. And labeled every cable as I made them.

(As wires get into the multiple-0 gauge, they and their connectors begin getting more and more sumptuous as well as expensive if you fuck it up)

I avoided making something intelligent like Super DEANSBUS and instead just went for the good ol’ Hong Kong Soldered-Shrunken Squid. I only needed four ESCs and an auxiliary connection (for receiver power).

Prepped and ready after a couple more hours of soldering. I’m very much now used to crimp tooling and contact systems used in commercial/industrial connectors. The R/C world really needs a “crimpable bullet connector” of some sort (And I don’t mean these trash-tier things), because solder cup filling for dozens of wires just takes so much manpower.

And here it is!

I was very much right when I said it would drive differently depending on if I had the arms down or up. If the arms are raised, the back two wheels basically aren’t there – it drives like a 2WD bot and is almost too squirrely. Overhaul 1 had similar issues, but the long triangular pontoons damped it a lot.

However, if I drop the arms down and preload them into the ground even a little, it will transfer some weight to the back wheels, unsquishing the front wheels just a little. It gains 4WD-like traction, but still puts substantial weight down on the forks. I actually managed to accidentally sand a good mount of the forks off on the bottom driving around in the rough concrete area of the shop.

This is a desired result. If I make sure Overhaul can sink down a good half inch or so in the front when the arms are raised, it means I have a fairly large band where the arms can be down and the bot still retain full traction. OH2.x wasn’t capable of this – the small wheels deformed so little that it propped the front 4 off the ground, making it act like a front-dragging 2WD bot.

On my mind now is a good way to make an easily adjustable travel limiter so I can, if need be, just slam the arms down without having to modulate them carefully. On this bot, if I drive them down too far, I can get it to start behaving like OH2.X – turns become more difficult and less predictable as the rear of the bot is trying to pivot around a drag point in the front.

The final weigh-in is pretty much on the money minus the weight of the wires, which I didn’t put in a simulated blob of copper for. The CAD weight was 26.7lb. Looks like either way I’ll have around that 3 pounds to play with to install a counterweight on the back plate!

Stay tuned for some exciting Orlando Maker Faire coverage, where I’ll get to find out if everything is wrong.