12 O’Clocker & MassDestruction 6: Where I Rebuild a Bot After the Event is Done

LET’S GET BACK TO SOME ROBOT CONTENT!

I feel like this website has become the Life of Charles, what with real editorials and non-stop round-the-clock van coverage and my tenuous professional aspirations… This is not the man I know. Where has he gone? *looks at own hands*

But now I’m back, with some new developments for Überclocker in preparation for Motorama coming up next week, as well as 12 O’Clocker stories to tell first. This bouncy little thing has been going to events and demos since 2013 with hardly any changes – just switching motors, basically. It’s gotten sufficiently worn down to a stub in the past few months that I decided to do a full teardown rebuild with some new parts!

To tell this story, we go back to the dark days of MassDestruction #5, like 3 months ago… Wait, CAN YOU BELIEVE THERE’S BEEN 5 OF THESE THINGS ALREADY? THAT’S MORE SEASON THAN BATTLEBOTS please take me back greg ;~;

This MassD, I took a more organizational role, helping judge and run matches. However, this didn’t prevent me from putting 12 O’Clocker (at the time, my only working bot -_-) into the arena in the somewhat informal 12lb Sportsman’s Class, where pretty neat matches like this occurred. MassDestruction has become a popular regional attraction; word has gotten out, and we pretty much filled out the Artisans’ Asylum event room to capacity. Like, look at this photo.

This is “filming a music video using the flashmob mosh pit at your post-phlegmpunk band’s free unannounced concert” level stuff. What’s better is that the builder population is getting more and more towards being newbie-dominated. This is a great problem to have.

12 O’Clocker came in 2nd place (out of like….3?) at this event, which was great, but it did take some damage. For the deterioriating ABS motor mounts that retained the lift motor finally gave out completely, wrenching the drill casing apart under its own torque:

Oooooh, that’s not good. I finished the tournament using a found drill motor given to me by an Artisans’ member, unceremoniously hot glue MIG-welded into the remaining mounting block pieces. At some point in the final against Snek Plissken, I also lost the lift motors which turned out to be one of the logic capacitors on the old RageBridge 1 units in 12 O’Clocker just breaking off the board. I also ended up demolishing another motor pinion just like at Momocon; the most recent set of motors for 12 O’Clocker came from some 12V Ryobi drill motors, and it seems like they were not up to the task of being run at ~20 volts.

Fast forward another 2 months, and MassDestruction the SIXTH! was on the horizon.  With the promise of more rematches with Alex Horne’s not-Sewer-Snake, I decided on a quick tuneup by replacing the broken ABS lift motor mounts with MarkForged Onyx prints because of course I did. New drive motors were also on the docket.

The Rage Panel slides out from the bottom, so I took the bottom plate off, which also let me do a hardware inspection on parts of the bot I rarely touch after finishing. This level of surgery was also needed to finally detach those ABS blocks.

So new drive motors were a bit of a conundrum. When 12 O’Clocker was built, it was still common to find generic cordless drill motors with 9-tooth pinion gears and 36:1 reduction (two 6:1 stages, 9 tooth sun, 18 tooth planets, and 45 tooth ring) gearboxes. Nowadays, it’s almost impossible to find these kinds of gearboxes, with 24:1 being the most common such as being found in all of the Harbor Freight 18v drills and most other rebrands. The 24:1 boxes have a 4:1 first stage using a 15 tooth pinion.

Trouble is, 12 O’Clocker was already geared to go fast, and dropping the gear ratio another 50% would have made it impractically fast and probably burnt out the motors in short order. Those Ryobi drill motors that I kept slipping the pinion on were attempts to find more 9-tooth motor pinions to fit the existing gearboxes.

 

After some haunting online, I found that one of my usual Amazon suspects uxcell sold 18v rated 550-sized motors with steel pinions already installed. Well imagine that, a prepared artificially flavored drill motor!  So I got a bunch to play with. They certainly look like 550-size motors and quack like them. The cans are a little thin, pretty typical of a mature Chinese genericized product… I can pick them up with a screwdriver. Every possible area of cost cutting has been well optimized!  The bronze shaft bearings obviously have no oil in them, since they are a little rattly, but a drop of motor oil in each solved that.

What I did notice was that the pinions’ press fits weren’t that tight. It was actually easy to undo them with a flat-blade screwdriver alone. To pre-emptively avoid embarrassing public gear slips, I took the pinions off and repressed them with a healthy dose of lime-flavored Loctite.

You know what – I’m just all giddy at the fact that they’re motor-shaped at all.

At some point in one of its tournaments, 12 O’Clocker either fell off a Dragon Con stage and landed on its main sprocket, or I got beaned by some flying robot, because the sprocket developed a flat spot which caused the chain tension to vary cyclically, leading to some lost chain moments.

In a moment of either desperation or brilliance, I decided to use my Harbor Freight slide hammer kit with a hook end to pull the sprocket rim back out like you would pound a very reticient dent. I bought this originally for van repair, but it looks like it works for robot dent pulling too!

Putting things back together, sans battery. The Ragebridge 1 with the missing capacitor had that repaired; the capacitor ripped out a logic power trace when it fell off, so it just turned the controller off. All the caps were securely Goop’d in place after the replacement surgery. If you’re using a Rage or a Rage 2, you should do this just in case also.

The biggest problem plaguing 12 O’Clocker was its battery, which I balanced once in 2013 and never again since. The cells had drifted far enough apart since then such that two of them flatlined at MassD #5, and I could no longer revive them. This meant I had to cut the battery open and undo the cell joints to the point where I could pull the two dead cells out and replace them with fresh cells. I closed the battery up again after this replacement (the green tape is new and covers the modded solder joints) with some thicker heat shrink, and making my charger do 5 overnight balance-charge-to-discharge cycles evened the cells out.

One last mod before MassD #6 was the permanent resolution of the clamp motor coming loose. The threads in the face of these Pololu 25D HP motors had completely stripped, so the motor was really just holding on by the electroweak interaction at the end. To remedy this quickly, I just took the faceplate off, slammed a #6-32 tap through them both, and then countersunk the original mounting holes in my actuator body. #zerosigmas is best Sigmas!

If you use these motors, or any of the similar motors from Servocity or Kitbots (or the straight shit from eBay), make sure to also take the motor off, clean the area, and use blue Loctite or similar threadlocker on the reassembly path. The motor does like to also wiggle loose – this is what the “battle hardening” mod offered by Kitbots helps prevent.

So anyways, it’s the morning of 1/28. Time to….

literally all the robots

This is what I trained for.

That’s Overhaul, Sawblaze, and two lift carts in the back. With space for another smaller heavyweight, or a dozen 30lbers and tools & equipment. And probably like 27 people. Some times it’s nice to just bring the U.S.S. BROWN C. STENNIS to an event.

This time, the event was held at the Charles River Museum of Industry, in one of their large event rooms. I once again helped with event logistics including box setup and judging. Overhaul and Sawblaze were brought along for visual stimulation, which was unfortunately because the event room has neither loading dock nor wheelchair ramp, and was, of course, a New England First Floor – 6 feet up the stairs.

Running 12 O’Clocker – especially when things started breaking – and half a robot show at the same time was a unique and singular experience. I will never do it again.

Have some 12 O’Clocker matches!

The match against Don’t Step on Snek, a.k.a Snek Plissken, a.k.a Sewer Snek… god dammit Alex, pick a name already!

By this point, 12 O’Clocker had lost basically all of its forks. They finally reached their fatigue limit at this event, one by one breaking off, until I had basically a big spatula. In the match prior, the right side motor pinion slipped its press fit as I had feared, so I went into the final match (also against Alex) one-motored. Which is fine, since Alex at this point had also started to run out of motors. The finals match was such a headdesking, facepalming occasion that I’m not even going to bother finding a video.

Poor 12 O’Clocker before the finals with the forks arranged the best I can, so SOMETHING AT ALL is still sticking out ):

Well, that’s it for the event. I broke the damn thing so much that I felt like I might as well use the momentum of the event to make spare parts. As I needed to also waterjet-cut spares for Überclocker, I threw on replacement forks for 12 O’Clocker in the same run.

Tearing down the bot completely up front to replace the fork components! This is where I discovered that despite my best attempts at anti-seize grease usage, the lift sprocket’s hub had galled onto the aluminum tube shaft, so the slide hammer was needed again just to break those two apart. I reamed all the shaft collars out again and cleaned up the aluminum shaft surface. This time, I tightened all the collars as much as I could – no longer relying on clutching the lift sprocket for torque limitng, but just setting the RageBridge current limit low enough that running into itself will not cause problems.

The new forks are slightly modified from the current design by adding more meat to the areas where the tie rods pass through. This was previously where they broke, so I made sure to add at least a majority of the cross-sectional area found in the rest of the fork.

By the way, this tube-removing service is also a problem with Clocker, especially after everything got twanged far up its own ass at the Franklin Institute event. I’m going to reconsider using a live shaft with shaft collar hubs to the forks for this reason, possibly considering a more Overhaul-like tie rod and central hub approach. Otherwise, I’m going to make an attachment for the slide hammer specifically for this purpose!

And here’s the refreshed 12 O’Clocker! Hopefully a staple of many demos to come.

Franklin Institute 2016 – The Post-Event and Thoughts on #season3

So now that we’ve gone over the build of Clocker 4, it’s time to talk about how the bot did! The Franklin event was one that I went to the first time last year, and it was quite the experience – if not extremely busy since the whole tournament has to be finished in 1 day.

Everything I needed for this event fit on one handtruck. See? Why can’t we just build 30lbers for BattleBots? Film the whole damn tournament in macro so they look huge!

I was prepared to take a few last-minute MITERS people, so I showed up ready to go. However, plans suddenly changed…

Mr. “I’m not sure if I’m going to go and it’s 9PM the night before the event” decided to take 30lb-SawBlaze. Given its reliance on conventional lithium batteries, we had to really quickly make a replacement battery using 18650-sized A123 cells pulled from my stock, using the last minute MITERS robots’ prep time to do this. This battery furthermore had to fit in the former space occupied by two flat LiPoly packs, so it ended up looking like a weird laptop battery. The vertical cells leaked into spaces the flat packs did not, in order to get some more battery energy.

MegatRON/30-Sawblaze also uses the Axiii motors attached to P60s, incidentally. That means we’re well matched for speed and power. This should get exciting!

Five hours later, we emerge out of hyperspace into the orbit of Philadelphia, only losing $26 of toll money in the process. On the way, I stopped in Manhattan to pick up two spontaneous teammates, Cassandra and Allen-chan (for whom this is public notice towards to put a real damn website together). Cassandra took most of the photos to follow, since I was too busy running around headlessly.

 

All set up and ready at the event, with a pipefessionalism to the left.  The pits at Franklin are always tight due to the space available, so I actually shared a table with Jamison. Getting pointy 30lbers in and out of the aisles was always a dance routine.

What’s that on the back of Clocker? Why it’s chibi-Haru-chan! Join Cynthia in a month of drawing cute chibi-style BattleBots entries!

IT’S ROBOT FIGHTING TIME! In the Red Sharpie Blob, it’s… god dammit Charles, get out of here, you’re not Faruq!

Clocker’s first opponent was Melvin, a modular pushybot with different pushy type attachments. It was a fairly easy target to grab, and I didn’t feel particularly threatened by it so I took the time to get to know the drivetrain better. I got a few good grabs on it, and then….

…whoops. After those good slams, the upper jaw just comes off. Well, this is disappointing, but I can’t say that the dislocated look isn’t neat in its own way. The weak link was the linear actuator’s leadscrew anchor.

I had two 1/4″-20 set screws – the same kind that took out Overhaul – holding onto the leadscrew in a notch, but I guess the force of the lift and clamp crashing down was enough to tear the end of the notch, and off the leadscrew came.

This was resolved by using two oversize drill bits to drill deep dimples into the location where the set screws landed, turning them more into pins. I didn’t have issues with this the rest of the event.

So far: 1/0. Here’s a video of the first match against Melvin!

My next match was none other than Mr. “I’m glad there was still a registration spot open when I got there”, 30lb Sawblaze a.k.a Megatron. This was a spoiler for #season3 excellent driving and maneuvering match that I just barely lost. Having weight on the front of your robot still trumps (We need to find a new word for this activity eventually) any amount of fine compliant wedge tuning, I think. I was hard pressed to attack Megatron head-on, so I concentrated on keeping it rolling over and self-righting, but there were more moments when he had control. Once Clocker was propped on the prongs of Megatron’s plow, it was more difficult to un-prop.

Near the end, Clocker was stuck upside-down momentarily. I thought it was the DeWuts clutching out, but looking at one of the match video angles showed that Megatron had spun off one of the nuts that holds the cross-fork tie rod together, and the tie rod was fallen out and jammed between the forks and pontoon. It took several seconds of forcing it back and forth before it finally bent enough to let me flip back over. However, in that few seconds, I lost significant mojo with the judges.

So far: 1/1. Here’s the exciting maneuvering match!

Some nice sparks coming off Clocker’s pontoons from the sawblade!

After this match, the rear wheels were basically worn flat. This is fairly consistent behavior – a few Motoramas ago, Clocker ran out of wheels. After that, I was replacing the duallie BaneBots 50A durometer wheels once per tournament. This version of Clocker combines smaller wheel contact area with a lot more drive power, so I was expecting to burn them down faster. There’s still a lot of “eraser flakes” going on, so I might want to look into a harder compound or just more durable material. I also openly admit that my casting technique might need some work.

The front wheels suffered less, since they were unloaded somewhat by the pontoons. I’ll add that having the pontoons firmly on the ground was not that helpful – I felt like I had traction issues, but it was really the pontoons and forks making the bot act like it’s front-heavy. It drove much better if I had the forks up a little. This is actually good to know for #season3, and I’ll talk about that later.

Some nice gouge marks in the pontoons from being held under the saw for a few seconds!

This is the cause of the jamming. The threaded rod tying the forks together backed out – most likely due to the saw, given there’s a significant cut mark on the standoff like someone took a poorly sharpened lathe parting tool to it!

Alright, I had maybe 10 minutes until my next match (Franklin runs FAST – you aren’t guaranteed the usual 20 minutes of repair time). Can we change the wheels in time? I brought my pack of spares  that were cast days before. This batch had air bubble problems, clearly visible in the wheel, since I could not locate the makerspace’s vacuum mold degassing chamber. Someone probably ran off with it for New York Comic Con. I was curious now about how the airy wheels will wear down, so I swapped them on anyway.

The next match was against Duck Yeah, a vertical spinning “STD” bot (where STD has now become popular robot slang for Single Tooth Disc). This is architecturally similar to BattleBots like Witch Doctor, Brutus, or Hypershock, so I was excited for this match. I don’t have a good tactic against STDs or other vertical wedged weapons besides “Don’t Fuck Up”.

Well, I did. My penchant for backsliding into head-on assaults did not end well. In fact I fucked up almost immediately, and the pontoons and arms bent up enough for it to be almost impossible to get back under Duck Yeah.

I got tangled in a hit shortly after that which let Duck Yeah go Full Mike Tyson and nip off one of the ears. These ears were definitely more risky than Overhaul’s – I got stuck sideways on them once while the clamp was open and I forgot how to self-right. Overhaul 1 and 2’s self-righting do depend on the clamp being closed past a certain position, which is easy to forget without practice. PRACTICE DRIVING YOUR DAMN ROBOTS!

The bright red glow coming from the middle of Clocker is the clamp motor’s endcap which got blown off in an impact – the brushes are touching and heated to incandescence by the current flowing through them!

Match video here. About midway through, I gave up on lifting since the pontoon edges were mangled and the forks bent, and just drove it around slamming it into walls more.  I won the match on this basis.

 

So far: 2/1

The ear that got nibbled split pretty cleanly along layers. You can also see that the weapon made contact with my clamp motor at least once!

Alright, not much more time until I have to get back in the box, so I quickly swapped a spare clamp motor in. This actuator, thank goodness, is far easier to service than the previous ones!

One thing I did not have was spare forks. This was a pretty severe oversight, as I had the ability to cut them out the week before and dd not do so. I also didn’t have a big enough press, or enough time, to straighten them out again to a degree that would be useful. As such, out comes the angle grinder. I’d rather fight with 1 fork than two are are kind of at different levels.

After this bold move, I try testing the repaired clamp arm and……. nothing. The motor wiggles a whole lot, but doesn’t really move the leadscrew. Uh oh…. I pull the thing apart and discover that it had a totally different pinion. I grabbed a motor for an incompatible drill out of my bin, went “LOOKS OK FROM HERE”, and threw it in the parts box! The gear was similar in diameter, so it “kind of worked”, but really didn’t. Cue 10 minutes of trying to find either a replacement motor or a pinion puller – someone came through with the latter, and I was able to transfer the pinion off the destroyed motor.

The next match was another cripple fight against a decidedly less mobile Melvin. This time, Melvin busted out a thwackbot assembly since they could only spin in place with 1 functioning motor. This was a match where I drove a little harder and went for broke. I had so little time after discovering the motor mishap that I left the ears off. Nontheless, it was a match full of a few full power, cross-arena drives which I had not attempted up to that point. One of these dislodged the bumper inside the arena!

Here’s that match. Near the end, I stranded Melvin sideways on the bumper. I generally have a policy of freeing opponents if they get stuck once, but if I get them twice, I’m done. 3/1 now, and Clocker moves onto the Loser’s Bracket finals (aka the most winning of the losers!)

And who was my next match? A rather crippled Megatron, who just got recently bounced off the ceiling by Big Ripto, in an event which called into question the integrity of the arena. This match wasn’t long – Jamison didn’t have enough time, nor the means, to reattach the plow in a way beyond large quantities of what he calles “Harambe Tape”. Nor was the saw functional. So the plow fell off early on and he decided to call it. Here’s the match from Fred – this put Clocker in the finals at 4/1….. against Big Ripto.

The finals didn’t happen. You can tell because here’s a photo of Clocker still in one piece. The event organizers decided to ban Ripto from the arena again citing the danger of ejecting parts from the roof. This was made known to us when the organizers pulled Kyle and I aside and had a chat about the arena falling apart. While there was some rock-paper-scissors involved, I handed the victory to Kyle unconditionally. There was no way I would have stood a chance in the shape Clocker was in at this point, and Ripto had taken literally no damage. It’s a rock solid design that’s hard to counter, especially when nothing on the front of your bot lines up any more.

I just made the organizers promise to match Ripto and Clocker up first thing at Motorama 2017 next year. By then, hopefully my strategy against vertical weapons will be more evoled. That ought to be funny.

So that’s the story of how Überclocker 4 / 30-haul took 2nd place at Franklin 2016!

On the way out, we stopped for dinner at a place I was explicitly recommended to go for the best Philly Cheesesteak. While I agree that it was very good, we all fucked up on a very important aspect: Not realizing the place offered toppings. Now, up until this point, I had never ordered a geuine Philadelphia-sourced cheesesteak sandwich, so I thought it was SUPPOSED to be just an amalgamation of meat and cheese. Again, this was a very good amalgamation of meat and chese, but it could have had onions, peppers, bacon, more cheese, more bacon, and all sorts of sauces on it for no additional charge. So I lost this round, and will need to correct this next FI.

In the end, how does this event affect my outlook for #season3?  The “lessons learned” fall primarily into the strategic, but there were also physical results.

  • First off, the molded wheels worked excellently. They did wear quickly, but not unusually so. I would have actually accepted consuming a set of wheels per match. That’s actually why Overhaul ended up having so many spare wheels made. So the task at hand is to investigate more compounds and see if one or the other yields better wear life while not giving up traction. In terms of raw traction, I was satisfied. I’ll probably commission a few pull tests on a steel panel covered in the same “traction paint” as used in the box, on a small scale first with promising candidates moving to Overhaul-sized 5″ wheels.  While there were times I thought I had poor traction, it was largely interweaved with the ground force exerted by the forks and pontoons.
  • Speaking of which, I’m thinking some system of continuously adjustable ground force is needed.  Clocker begin the tournament with pontoons slightly too low, and this obviously impeded maneuverability since it preferentially loaded the rear wheels and left the fronts almost unworn – hence wasted. After some big hits, the pontoon edges became worn back and I actually began driving better as evidenced in my second MegatRON and Melvin matches. In fact, this is something Beta has the ability to do. I can pre-load the shock mounts using different height spacers, but it would be nice to have a set that’s adjustable in height somehow. This is to make sure I can perform fine tuning of the contact while Overhaul is loaded up in the test arena for functional verification before the match. I’ll have to think about if this system is worth pursuing and in what form it will manifest, but I want to MACHINE THE PAINT OFF THE FLOOR (so, you know, I can get better traction).

 

  • Likewise, I should think harder about an adjustable hard stop for the arm travel. Clocker 3 had one, but Clocker 4 just relies on the frame rail. This is not adjustable and obviously the zero point will change with damage. Same goes for Overhaul.

 

  • I’ve got a lot to learn about driving strategy now that I’m back in the high energy class. It’s completely acceptable to attack Sportsman’s class bots head-on since the chances of you exploding doing so are minimal, and this has clearly influenced my attack style with Clocker, since the ‘smash and grab’ visual is also an audience pleaser. This is obviously dangerous if you are liable to being fed into a vertical drumlet. I still consider the vertical wedged weapon the most dangerous adversary, given that Overhaul has taken on a high powered horizontal weapon well (okay…. you know what I mean) and Clocker fared so poorly against Duck Yeah. Ripto would have been a disaster for sure.

 

  • It’s very obvious  that I cannot count on every part of the bot lining up to make the front impregnable. I used to drive pushybots with hinged wedges which were lightly pressed against the ground. This, besides not interfering with traction unlike hard-mounted wedges, also affords a chance to escape if you go up on the opponent. In the first battle of MegatRON, Clocker was constantly getting stuck on the attack phase since I would charge into an equivalent charge by Jamison. It was also well evidenced against Beta that Overhaul was hard pressed to escape getting wedged. How to prevent this without compromising the function of the pontoons I am less sure – it could very likely just come down to more strategic driving.

 

  • I furthermore have some thoughts about minimizing my defensive cross section against vertical wedged weapons that I will keep offline for the time being. The upcoming MassDestruction event in 3 weeks might be a good chance for me to test some of the ideas on the beetleweight scale, where drums reign supreme. I’m tempted to build a simple beetleweight pushy-wedge (sigh) to exercise my skills and countermeasures against vertical weapons. (It’s important to note, however, that nothing scales directly; concepts can be expanded, but I can’t magnify everything I did on Clocker by 2x and expect it to behave the same way)