Archive for the 'Events' Category

 

ORIGINAL CONTENT! The All-Around Robot Update: Roll Cake Rises Again; Dragon Con 2017 & Uberclocker

Oct 02, 2017 in Bots, Events

Whoa, what happened to this place? Everything’s so dusty and gross. Why is there a pile of circuit boards on the bench??

*trips over Chibikart on the ground and dies*

Hey, remember: whenever I disappear for an unexplained period of time, it’s always because I’m working on something hilarious. This time it’s extra hilarious, I promise! Obviously I’m always itching to keep everything updated here on my latest, but just like the first BattleBots build season, externalities which if broken would make other people look like assholes prevent me from saying anything at the moment. See, I don’t mind me alone looking like an asshole…

Anyways, backing up a little in life, I decided to redesign Roll Cake from the ground up following my hub drive experiments earlier. MomoCon came and went, but the Hobbyking orders kept stacking up, so I decided to roll it all in with Überclocker’s changes for Dragon Con!

roll cake

It all begins with a wheel.

Doing the drive test with the SimonK ESCs and the Multistar 460kv motors convinced me that the hub motor direct drive would work out, at least better than the previous BS I tried to do. I went shopping for high pole-count, low Kv drone motors since they’re pancakey. The plan was just to approximate wrapping an O-ring as close as I could to the motor. I ordered a few of these AX4006 motors for their combination of weight, low Kv, and high pole count.

Roll Cake is a bot which faces some packaging difficulties, since the middle of the bot has to be left pretty open for the flipper linkage. It would actually be easier in a 12 or 30lb design, since ‘noise floor’ of part sizes is much smaller compared to the bot size. If I scaled this design up to a 30lber right now, those would basically be 6″ hub motors, which is unnecessarily large.

There’s other architectures and shapes for the bot which might alleviate this, but for the time being I decided to try and keep the cheese wedge shape but  make it a little more…

…round. Remember that the flat sided shape was just an attempt at vomiting my vision of a bot that I’ve had for a while now, not making sure it works. When you ditch the need for 6WD, things get a little simpler! Even this is technically unoptimal packaging since there will be a lot of wasted space in the narrower parts of the cheese wedge. I’m basically just reskinning Roll Cake v1 and using all the same parts, since the goal is to get it driving and flipping things reliably, albeit not spectacularly, before deciding what aspect of the design to improve.

Once I had the parts placed reasonably, I started generating frame features to accommodate, such as wheel cutouts and future bearing blocks. The chassis will no longer split in the middle – that required so much extra effort to get everything to line up. Instead, I’ll be splitting the rounded caps next to the bearings off as its own print in the future.

The previous image showed the old linear slider trigger, but packaging necessitated switching to a swinging style. This means Roll Cake won’t fire when upside-down with the drum running in reverse – I’d still have to ‘self right’ so to speak. That’s fine, since I’m also ditching the double-sided linkage due to it taking up the entire center of the bot from swing space. At least keeping the flipper single-sided lets it still have structure in the middle!

The chassis is now taking shape pretty well, showing the swing trigger’s backing and “drilled” bearing cap holes and the like. I’m designing this to print ‘upside down’ on the flat top face.

After defining critical part anchor locations, I hollowed things out to accommodate the flipper linkage and irritatingly rectillinear things like batteries. Seriously, if there’s one thing this design is sorely lacking, it’s a battery worth having. I much prefer this to be 4S, but can only fit a 3S pack of adequate capacity for now.

As I model the body, I can give components final homes constrained by mounting holes and then adjust the cutouts and spacings to fit. So there was a fair amount of tuning going on at this point, including a change of wheel size to be smaller in order to shift the wheels more rearward (to give me battery space!)

After that, the fun part became linkage design. The goal is to get a linkage design which travels as far up as I can manage using the roughly 1″ throw of the cam ring, and generally has no linkage interacting at more than 45 degrees starting angle.

My insistence on a “pull” action on the main cam linkage means I have to transform the motion through a bell crank (the bottom and right side short line) to become an upward motion. Strictly speaking, I could potentially accept a push action from the cam linkage and that can directly interface with the flipper arm and move it upwards, but it would need to be designed much more heavy to stand the compressive force instead of tension (pulling) force.

 

This bell crank itself went through a few revisions in order to minimize the impact it has on the middle of the bot, the large bulkhead that runs across the two sides.

Here, I’m comparing designed linkage travel with actual part placement, seeing how much of the middle of the bot has to be cut out. The bell crank center distances and topology have also changed. The previous design intruded on the center of the bot with its full height, whereas this “T” design means only the short leg of the T pokes through the center bulkhead.

Then I decided to wrap the bulkhead around the bell crank instead of hollowing it out pre-emptively. It’s all going to be 3D printed in 50% density anyway, so no need to pre-emptively deny myself cross sectional area (which is very important to 3D printed parts)

After I was satisfied with the bell crank geometry, I made a crude flipper arm model to start out with.

The linkages will have to fold into themselves a fair amount, so I pre-emptively carved space for them before doing anything else.

The intermediate linkage is a bit of an awkward shape – here it is taking form. It has to adapt the narrow bell crank to the wide flipper linkage. I decided to do it here, and reinforce the middle of this linkage with a big flange, instead of trying to flare the end of the bell crank wider due to my desire to print it flat and have fully un-interrupted perimeters to maximize strength.

Here, see the aforementioned flange in the center of the intermediate linkage. I’ve now hollowed the flipper arm, which will be top-skinned with hardened spring steel.

The armor for this bot is quite simple – primarily Onyx in massive hollow-ish sections for the crumple zone effect, and blue-temper spring steel covering the important parts and providing access hatches.

I added a little feeder leg next to a region with unused material thickness. This will be a machined piece which is captured with nuts and flat-headed screws.

Finished and ready for printing!

I had to split the geometry first into the printable sections. I extracted the bearing cap by making a 5-sided surface box in Inventor and using a split body by surface function. Only one was needed – the other was disposed of. Other sections such as the mostly empty tail were cut off also in order to reach the print volume, and they were designed to be bolted back on.

A day later… Her’s the frame finished, printed in 3-perimeter 50% density Onyx. Ought to be plenty!  You can see where I cut the end of the wedge off and have modeled in a few tappable holes to hold them on.

Here’s a pretend-o-bot to make sure the dimensions all fit. The bearing cap was something I was particularly nervous about. I didn’t design clearances into the linkage parts to save design effort (read: I’m too lazy to make proper constraints) so some filing was needed to get them sliding freely.

Hardware installation time! I made sure to make little access ports for the motor wires, because wouldn’t that be embarrassing?

We move now to my old high school workbench down in Atlanta, which is somehow still there and in operation (maybe being 16 feet long has something to do with it). I got all the mechanical hardware installed before leaving, and decided to save the wiring for the Dirty South.

Pictured in the foreground is my new best friend: the itty-bitty-baby-offset-screwdriver-bit-ratchet. It’s McMaster part number 52725A31, and it’s positively adorable AND the only way some screws on Roll Cake are accessible at all. I designed it this way, so it’s legit, right!?

 

As usual with this thing, wiring is a disaster. The ESCs of choice are the Afro 30 Race with SimonK set up to do reversing with my usual tricks. They’re small, but not THAT small. I decided to keep the ESCs on the same side of the bot as their motors in order to reduce the amount of long wiring runs, so there’s two on the right side of the bot and one on the left.

All the motor connections have now been made, and I left one task for last before I soldered the 3-pin signal wires to the receiver….

I had to program the SimonK firmware to activate reversing and braking and my preferred goodies. I planned ahead and made this servo to tiny-clippy-jiggle breakout cable which I’ve termed “The Simonator 2.0″ in order to grip the signal wires of the ESCs. While I could have programmed them all beforehand when the servo conectors were all still there, I decided I needed this cable regardless just in case I had to change something in the field, post-installation.

I brought the finished bot to one of the robot panels at Dragon Con. Sadly this year I fell off the bus and did not host any panels, but I’ll make sure that changes next time! I’m glad that recently, my Makers presentation hasn’t really been needed – in the most recent years I delivered it, the percentage of the audience who’ve experienced CAD or soldering LEDs together, etc. has grown immensely, in my opinion greater than the rate of self-selection for these things.

Here’s the linkage fully opened! Note the preponderence of little shoulder screws forming the joint pins – I standardized all of these to the same length to save myself from my historic habit of making my robots all shoulder screw nightmares.

….and now announcing my new 6lb multibot entry??? This is the head of Lucy‘s Mei cosplay, the freeze-ray dispensing Snowball. overwatch has ruined my life run away now

I’ll post some of the test videos of Roll Cake soon – I was happy enough with its performance in the garage in terms of drivability and flipping, even if it won’t prove that impressive in the box due to being repackaged test rig parts.

überclocker

We now move onto good ol’ Clocker, which has looked like this since Motorama…

Pretty depressing, eh? In the final rumble of the 30lbers, I burned out one of the SK3 4240 drive motors, so I was on the hunt for replacements, and Hobbyking didn’t have stock in that size at the time.

What they did have is a sale on their new NTM line, which had a similar size motor:

So I scored a couple of these – they were physically the same dimension, but unfortunately these motors were slightly faster again, so I was facing the very real prospect of Clocker hitting 25mph without much provocation, which could be a liability on the Dragon Con stage.

I emptied the bag of Clocker remnants to see what I could salvage and what I’d have to remachine – the answer was really basically everything minus the motor output gear :p

Good thing Clocker is legal in the new 30lb Sportsman’s Class rules enacted FRESH AND NEW this year for the Franklin Institute event in 3 weeks!

To extricate the motors, I had to disassemble the frame, which proved a little…. challenging after Glasgow Kiss gave it a once-over. There were some special extraction techniques I had to use here on this machined corner!

From the spare Clocker parts bin I extracted another section of the 1/2″-10 leadscrew and flanged bronze nut that fit it. I’d bought a few spares last year in anticipation of needing to machine them eventually, and here we are.

The bronze nut gets machined all the way down to be smashed into the bore of the modified Vex Pro spur gear. When the gear spins, the leadscrew gets sucked in and out of the nut, and its own reaction forces are taken up by the bronze bushings surrounding it. All solid, all friction, all the time, but it gets the job done.

I’d like to eventually rebuild Overhaul’s actuator in this way, except with preloaded tapered roller bearings, for #season3 whenever it ends up being :’(

 

Mate this up with new waterjetted plates that I drilled and tapped and we have a new actuator. The drill gearbox was reassembled from stock pieces from my giant decade-old (…) bag of Chinese cordless drill parts, using the original shaft which was not damaged in the fight. I have enough pieces now to straight up make two whole actuators, which is nice.

After that, I repaired the bottom plate of the bot by stitching new holes in between the hole ones. I’m not sure if I’d use #4 screws like this anywhere in a loadbearing path (which the top and bottom plates do count as) if I redesigned Clocker again, since the indirect shock loads from the 30lb Featherweight class alone (in the form of getting socked by a spinning weapon) is much higher than Sportsmans. One of the corner hits from Glasgow Kiss sheared off a half dozen of my bottom plate screws just by momentarily bowing out the frame enough.

 

While I was in there, I swapped in the spare wheels made from 60A Mystery McMaster Urethane (actually OEM’d by Forsch Polymer, the most 1997 company extant in 2017). The white Smooth-on Simpact wheels had worked well enough, so I wanted to see how these would do.

Well, everything is technically ready for reassembly!

I rememberd a much better way of taking the entire top off Clocker. Previously, it involved trying to drive the center lift shaft out through ALL of the components that were shaft collar’d onto it. This was patently painful. Unlike Overhaul’s unboltable lift towers, Clocker has solid ones built into the frame rails. It turns out if I just unbolt the outer and inner frame rail on one side as a unit (9 screws), there’s enough room to wiggle the shaft out of the bearings and pop the whole thing off.

 

Clocker was the last thing I wanted to put the Brushless Rage test units in before shipping them off for production. The severely under-geared high-Kv motors will be a good stress test for the architecture, since on the Dragon Con stage I’ll mostly be driving at low speeds and turning/reversing often.

Check out that little Onyx bracket I made to hold the units. I wanted to place them flat against the frame rail behind them here, but this arrangement kept the wiring cleaner and away from the outrunner motors.

A new waterjet-cut gear and some quality Taki-time later, and everything is now back together. I did some drive testing outside, which showed me that the Brushless Rages were working great even under duress – the gearing on the motors is low enough that the bot has trouble turning in place on a high traction floor. So here I was hoping that it would be even able to turn at all on the Dragon Con stage carpet! But once it takes off… boy does it want to keep going.

the charles and the dragon con

Welcome to Dragon Con! Have a van.

I would have loved to bring VANTRUCK instead this year, as it has been now impeccably reliable after its lobotomy and subsequent headcrab installation, but could not even begin to justify the 9 miles per gallon each way. It’s beginning to dawn on me that the kind of person who would have bought one of these things new, never ever thought about the cost of fueling and ownership. I’m not quite to that level in life yet.

Overall, this con worked out a lot differently than some of my past Dragon Cons. See, I wasn’t scrambling to finish a robot every day for once – Roll Cake’s finishing work and testing occurred before the con started. Instead of trucking around a giant transforming mechanical prop, Cynthia instead prepared a bunch of pieces for the Dragon Con art show (which as I found out was nontrivial to get into)

On top of that, it’s become more of a yearly reunion for some of the BattleBots competitors and friends who have moved around the country & world. For example, I found Lisa Winter!

The cotton candy committee has arrived.

I attempted to replicate her tattoos in the middle of talking at a panel. Nailed it!?!

And for the first time in probably over 10 years, I actually played in a gaming tournament. There was an Overwatch ruined my life run away now tournament being hosted at the convention gaming center, and a few of us essentially set up #BattleBotsPlaysOverwatch.

The house equipment was sub-par, though, so we didnt’ do too well – people who have clearly been to more than one tournament brought their own mice, keyboards, headsets, and pillows and stuff. Now that’s pro.

 

HELLO FOR I AM MECHANICALLY THEMED VIDEO GAME GANDER AT MY CURATED ARRANGEMENT OF MECHANICALLY THEMED ITEMS

Alright, you know how Dragon Con goes down. Let me spare you the details and get to some robots!

MicroBattles has grown to the point where it has to be single eliminations only and running across two arenas to keep up. I’m glad that it’s a good problem to have! However, it does mean you’re pretty much one-and-done.

There wasn’t much to do with Roll Cake beforehand except get some driving in. I decided to move the tail on the flipper downwards one mounting bolt such that it was more likely to rest on the floor – otherwise, the bot tipped abouts its wheels a little. However, it kept weight on the feeder wedge, so that was a plus.

Robot Battles features mostly local builders who kind of keep to that series of events around the Southeast. It’s refreshing to see bots which haven’t been forced to become the small monolithic dense bricks that most competitions have forced them into being. These two, for instance, are hand-bent sheet metal from Home Depot, with a hand-soldered custom motor driver inside. I honestly miss these kinds of builds.

Pool noodle wheels were fully in fashion this year, made popular by the Dale robot Noodles. Hey, they’re totally not entanglement devices. The wheels aren’t supposed to come off, just incidentally if you hit them with your spinning thing! Wink wink. I suspect this kind of thing might get roundabout-banned somehow, but on the other hand, it’s 2017 – get a reversible ESC on your weapon already!

Sheet metal everything, down to the weapon! Now this is robot fighting.

Other builders who had too much time on their hands chose to adorn their robots in….. creative ways. That’s hand trimmed and applied fake wood veneer vinyl on Margin of Safety here…

I was pretty eager to fight Noodles since it’s high ground clearance and invertibility would have made for a whole match of flips with Roll Cake.

Besides the wacky builds, you had your usual array of kit-bots and modified kit-bots.

Roll Cake was matched with Margin of Safety first, obviously a fight that I was hard pressed to win. Aaron put on the miniature vertical drum module for the match, so we went head to head trading blows. Margins having the the smaller drum advantage,  Roll Cake got flipped over and I spent a while trying to self-right, but at the time didn’t have any skids on top of the bot, so I trundled it around a few times trying to get him to flip me back over.

See the two little hex nuts sticking up from the top? That was added after this match so I could get flipped over in the rumble and maybe get back up. With the drum bouncing off the ground, it wasn’t going to get enough momentum to roll it self back over, so after a while of trying, I decided to save the effort for the rumble.

In said rumble, the drum promptly threw the rubber o-ring belt and jammed as soon as it started. Well bugger me with a #1/2-20 tap, that sure didn’t come up in testing! So I spent the whole time running around like an idiot.

I suspect that spinning up quickly made the belt stretch enough (since rubber cord doesn’t have a tension element in the middle like fibers) to jump out out of the pulley enough to get grabbed by the drum. In Roll Cake 1, the pulley spacing was far enough apart that it would have just fallen off, but this time I had to move the drum closer and so there is a lot of overlap with the drum iself.

Hey, all things considered, I walked out with a working bot. It’s now time to get serious with Roll Cake. I’m extremely confident in the mechanism now, and so it’s time for it to stop being a test jig on wheels. The weapon motor is severely undersized – if there was one design which should have a motor-in-drum setup, it’s this one! And, furthermore, freeing up the space occupied by the weapon motor might mean I could use more conventional drive motors. The hub drive worked well enough, but I still prefer the positive feel of a geared motor.

And now it’s Monday!

 

With the return of all the robotty TV shows, we’ve seen a serious and sustained rise in the audience count. The room filled up to this level well before matches began, and the line continued out the door the entire day.

An entry being finished in the pit area before matches begin! How quaint.

Lisa brought itty-bitty Tento, weighing about 8 pounds, and entered it in the 12lb class for fun. This thing was built as a “how to build a robot” demo piece. Unfortunately, it suffered a gearbox failure literally right before matches began and it was of a type that nobody else was using, so spares couldn’t be located. Sad day – maybe next time!

Clocker just needed battery charging (and the replacement of a chain tensioner block) this whole event, so I’m quite pleased.

I only ended up having two matches – one against this giant purple thing (which had radio problems at the end – notice us both running onstage to disarm it), and the second against Dale’s Pushy Grabber. This thing has been sweeping RB events (literally) with the lynchpin strategy of wiggling under your bot almost no matter what. Now, normally I offer at least some resistance to Dale, but this thing I had to approach either at a very specific angle or risk getting plowed off the stage almost instantaneously. We had 4 total matchups, in the middle of which Dale had to reattach one of the rollers and I had to replace a chain tensioner block which finally decided to wear through and fall off.

This event really showed that, much like my arena-optimzed Test Bot v4 days in the Late Aughties, wide ground-hugging wedge surfaces really are more of a liability on the stage than an asset. Notice how in the final Pushy Grabber matchup, I tried executing the same strategy, but got hung up on the edge just long enough to become vulnetable. The only weakness of Pushy Grabber right now is a long-reach forked robot like Nyx with the lifter attachment – Clocker did not have enough “stickout” to really get a good handle on it – nor did it really on other bots.

Unlike version 2 and 3 where the clamp arm reached all the way to the end of the forks, this one for the sake of looking more like Overhaul has the ‘grab point’ more inwards, so I had a harder time getting opponents into the clamp in the first place unless I took a straight run at them with some velocity – upon which I would often run into the stage edges.

I stuck around for Rumble #1 which I won by virtue of trying to get around the damn stage and mostly ignoring opponents…. and in Rumble #2, I just took the wedges off and ran around like an idiot some more, accidentally handing the win to the purple thing after doing some kind of J-turn rocket jump off the stage. Oops.

This event was also the final straw for me in terms of gearing down the drive motors more. I’ve been threatening to go to 2-stage gearboxes for the drive, and now it’s more necessary than ever. Clocker v3 was geared for 19mph and was already a rocket, and there was barely any need for it on the stage. I’ll probably move to 11:1 2-stage P60s and use smaller 35mm drive motors.

Yes, this kind of thing is legal here, with a catch: It doesn’t exceed either 500 RPM, or 20 ft/s edge speed.  It’s driven by a geared motor, so it will more lift your bot up and chew at it.

 

Replicas of BattleBots entries are the in thing right now! This is Tuskin Raider, a 12lb Razorback-alike that Jamison built. It got all the way to the 12lb finals.

This is a 12lb shell spinner.

And here we have the assembled Power Rangers shot of all the scale models. Hey, we can film #season3 right now if we just get all the cameras up really close. I keep bugging Jamison about why he didn’t make Tuskin a 30lber instead of a 12lber.

So that’s it for Dragon Con! Two working robots remaining, shenigans abound, and…. no van adventures. Wow, when did my life become routine? Obviously it’s time for another all-vans update soon….

Motorama 2017: The Event Report; Or, How Not to Scale-Model Test Your BattleBots

Feb 26, 2017 in Bots, Events, Überclocker 4

And we’re back! I must say, in a way, I miss the abject chaos (read: spinners) of the full-contact weight classes, but it is glaringly clear that I need to get my strategy back in shape. In all, this event was a good wake-up call for me if I want to play the BattleBots #season3 game seriously, but that’s for a later analysis. Here’s how things went down, starting with the finishing of Clocker a few days before.

One of my last to-dos was making spare armor wedges. I’d already waterjet-cut the plates, so they just needed to be cleaned and welded. These wedges represent a simplification of the design used on Overhaul that I would like to transfer. They’re simpler, reducing the number of facets and panels by half*,while also retaining the same lower-edge durability with a (higher mounted) gusset. However, they are missing the “Jersey barrier” double-angle front that Overhaul has, and this will be important later.

So there are four wedges – two are made from regular cold-roll mild steel, and the other two from 4mm AR500 plate. I’m really expecting to run the AR500 plate as primaries, and only ditch out to the mild if they get (somehow) demolished. I suspect there wouldn’t be much left of the bot if that were the case, but it’s good to have options! The 4mm plate one weighs several ounces more than the mild steel, owing to higher plate thickness (.125″ vs .140″) so I’ll definitely have to free up weight for it.

I jigged the whole thing up since it tabs together into itself and tack-welded the panels together using a TIG welder, before switching to the good ol’ spray-and-pray MIG welder to blend the outside seams together and drop a huge interior fillet into whatever edges I could on the inside. I am still the only person I know who tacks assemblies together using a TIG welder, and then switches to using a MIG welder. I write this off as me having zero patience for welding, but needing the initial assembly to be straight, so I do it with the precise near-zero-force application of a TIG welder.

*Note that Clocker doesn’t have forward- or side-facing wubbies like Overhaul, so if those features are being added back, it would increase the plate count, but still not to the point  where I had them for #season2

Free up weight? Where the hell else can I do that from!? It seems like Clocker’s been pretty well dieted, but a few weeks prior I had started thinking of do I really need semi-infinite drive power? in the form of possibly replacing the AXi motors. They work great, yes, but are definitely overpowered and therefore heavier than I need. I decided to swap to a set of 42mm SK3 outrunners, which would reduce me by around 4 ounces per motor, allowing me to use the AR500 wedges as the heaviest configuration. Power-wise, the SK3 outrunners would have been just fine. They also pair up with the pinions of the 4:1 P60 gearboxes from BaneBots I ordered (due to the higher Kv) and bolt to the motor plate with no modifications.  This is a great combo – I highly recommend it as a plug-and-play 30lber-scale brushless drive rig now.

The motors were basically the last thing to arrive before I had to leave, so I decided to hold off swapping the parts in until we got to the event.

motomumu

The following image shows the totality of the glory of America:

 

 

On Thursday night, we packed Literally All the robots into vantruck, along with a sizeable amount of tools, support equipment, and other miscellanea. I planned to get there early-ish Friday to help set up and also to aid in Antweight & Fairyweight tournament logistics. Along with me were SawBlaze and Overhaul for display at the front of the audience section.

Sadly, this trip as-photographed did not happen, but that is an entire other story that has to be told separately. Long story short, the haulage minus SawBlaze and Overhaul were reshuffled into Mikuvan. This is a great story, I guarantee you (if you stalk me on the Internet, you already know it, so no spoilers!)

Alright, so it’s like 2PM on Friday now when I get there and everything is horrible and nothing matters. Let’s swap the motors onto Clocker:

Boy, those ESCs – spares left over from Overhaul and Sadbot, Dlux 160A HV units – are now officially overkill too. That’s what happens when you make a parts-bin robot. With the motor reduction, I was able to make weight using the AR500 wedges. Also in the same disassembly service were the floor scrubber tires:

 

Here’s a better look at them. I liked how they handled in the test box – still just a little light on traction, but very predictable. I brought along the Forsch (black) 60A wheels also, but decided to run these first since the Forsch ones felt a little more stiff.

Fast forward to Saturday and….

I feel like I’m at some kind of  career fair or anime convention. The people-ocean density was staggering; this is the largest Motorama Robot Conflict historically, and the largest year-by-year growth (over 50%). A lot of new faces, probably 25% of builders, and also quite a few returning legends. It’s a good problem to have.

In the interest of not dying, the 3lbers (beetlewights) were basically running in a parallel event with an 8 foot arena just off screen to the left, with only large bots – 12lbers, 30lbers, and 30lb Sportsman’s – running in the big arena.  Given the sheer number of beetles, it was the only way!

What’s great is MassDestruction helped spawn several ‘newb-vets’ who cut (….blunted?) their teeth in the MassD arena over the course of the last year.  These are two of Alex Hattori‘s robots. At this time last year, he had a 30lber made of two steel bars welded to a cast iron pot, and since then he’s cleaned house at like, every MassD ever, I swear.

 

 

Some other remarkable bots forged at MassDestruction from guys who work at, uh, MarkForged. Crap, my sponsor is beating me at my own game! What do I do!?

Another one of my favorites return – this is Pitter Patter, a 30lb shuffler (actually 45lb in the weight class) which way back in the olden days of Motorama 2015 was the original design model for Overhaul 1′s shuffle drives, which were basically a direct knock of this thing! For this version, the saw got smaller, but the shufflers got way faster… like 3000 RPM fast. This thing was cookin’ it in the arena.

Basically, you’re not getting anywhere NEAR the whole story just from these few photos. I remember when robot tournaments were this big, from the momentum of the first run of BattleBots, and I hope I see the 2nd Great Awakening of robots progress further still.

Anyways, onto my matches! This is Glasgow Kiss.

Topologically, it’s a good mockup of the Cobalt match. This is okay too! I’d actually hoped for a vertical spinner opponent so I can practice my anticipated strategy of using the ünicorn. However, I’ll gladly try to practice my horizontal-fending tactics too. The high level plan is to come into his weapon tangentially using the AR500 wedges and bounce him around, ideally towards walls, and try to corral into corners. More or less the same plan as for when I fought Cobalt.

I mounted the ünicorn anyway in case it could be used – I wasn’t counting on trying to swipe the belt pulley, as it’s too far inwards.

So how did this match go? Uhhh…

Well that’s not very typical at all.

Let’s watch the match video to find out what happend!

Alright, so my strategy starts out working fairly well. I’d say about 0:30 is when things start going awry. While I get a few more good tangential shots in, Glasgow Kiss is able to get one or two shots in which climb up the wedges and take out the clamp actuator and main lift gear.

At 0:49 I make a pretty bad driving error and end up plowing directly into the blade, so the forks and clamp are pretty much done by then – you’ll see me raise them to try and keep them up and out of the way.

The last big connection throws both of us apart across the arena, and I’ve lost all drive power by now so I tap out.

What Andrew (driver of Glasgow Kiss) does well is pivot the bot on the blade axis – in part a consequence of it being so heavy – such that it’s hard to just ‘get around the back of’ or execute similar strategies. He does this several times to leak away from Clocker’s grasp succesfully, leaving me to chase while he spins back up.

If you watch closely, you can see Clocker has some maneuverability issues right away. One of them is the bot’s right side having a tendency to stop and not reverse, which means I missed a few in-place turns. This occurred to me as strange – I mentally wrote it off to the smaller brushless motors in the drive cogging on start, but it definitely didn’t occur in test box driving. The heat of the match kept me moving, though, and I elected to try and drive around the problem, exercising the tactics I outlined in how2brushless at the bottom.

So Clocker seemed to be in one piece still at the end. Time to appraise the damage:

Check out the gear carnage. This gear is made from 7075 aluminum. It’s a nice and rigid alloy, one of the strongest by tensile strength aluminums, but it’s really best used in bulk such as gearboxes or bearing blocks and the like, not in thin sections. The gear is fairly heavily webbed out for weight, so it cracked through readily instead of bending. A 6061 gear would have bent and I would have had a chance to sledgehammer it back to something resembling flat.

 

Glasgow Kiss machined off most of this corner here when I was turned around. I’ve thought about making plastic corner hoopy-jiggles before, but haven’t been compelled to yet. As a part of a comprehensive horizontal weapon defense strategy, it might be worthwhile to do for Clocker using some 1/4″ UHMW or a thinner spring steel.

D’oh. I think the cross-arena impact stripped all the #6-32 threads from the end of the gearbox, so I lost drive on this side. On the other side, the chain jumped between the drive sprocket and the rear wheel sprocket.

You know what was awesome though? The AR500 wedges, on both sides, are practically untouched. Lightly divoted, but they were still flat to the ground. I did write off two of the lower wubbles on each side which had some tearing damage beginning.

But you know what – this setup went head to head with one of the biggest 30lb weapons a dozen times and isn’t much worse for the wear. What it really showed me is that Clocker’s frame and armor is perhaps overly built for the weight class now that geometry is compensating up front for frame thickness.

By near complete accident I’d say, the ünicorn came THIS CLOSE to piking the pulley and belt.

Alright, it’s time to fix everything up. Both sides of the bot had to be disassembled to replace the drive motor studs with longer ones. Since the P60 motor plate screws don’t go all the way through, there was some thread left which I could use with longer #6-32 bolts.

It looks like the frame was tweaked about 1/16″ in a parallelogram shape, from a similar corner hit on the rear right side (opposite the well-machined one), so the left side drive sprockets became offset enough to cause problems.

Getting the damaged lifter parts off was an adventure that took a long time. I’m now heavily rethinking the clamp collars on live shaft approach. It was fine in the Sportsman’s class where Clocker never took any real damage there, but with everything twanged up, there was hearty use of deadblow mallets, aluminum pusher tubes (to avoid marring the shaft), screwdrivers, etc.

What I couldn’t save were the clamp actuator and lift gear. I had thought about machining another lift gear the week before, but it remained just a thought. While I had a newly assembled and painted clamp arm ready, I didn’t bring spares for the clamp actuator. Without a backup clamp actuator – since Glasgow Kiss had basically wiped all the internals out also – I had to push everything back together in “spatula mode”, just with the lower forks and around 120 useful degrees of gear. Once again showing the difference between Sportsman’s and the full contact weight classes – just like in BattleBots, you should really be prepared to build 2.5 robots, one full set of spares and another for the things which break the most often.

So I delay my next match (and run down that delay as far as I can) to get spatula mode together. When I finally hustled into the arena, though, I discovered that Clocker could only spin in place or turn right. I clearly had wired one of the drive motors backwards, but what? Moving only channel 1 in my elevon-mixed (single-stick driving, basically) radio only caused the left side of the bot to move, with no response from the right side. However, it could obviously spin in place; without a motor being backwards, it means it could drive straight forward or backwards, but only turn right with 1 channel.

Without more time, I had to forfeit my match against Shaka, who, I will point out, somehow went 2/2 at this tournament using only forfeits. It won its matches by forfeit, but had endemic electronics problems which caused it also to lose by forfeit… I am told that in testing shortly after our non-match, it blew up.

Back in the pits, it took me a little more investigation to discover that my Hobbyking radio had somehow lost a mix. When you configure a radio for single-stick driving (or Delta Wing, Elevon, V-tail, etc. for aircraft), you assign mixes to tell channel outputs to listen to certain combinations of stick inputs. Here’s what a typical simple elevon mix looks like for my Hobbyking T6A-v2 transmitter:

There’s two mixes involved – one to tell Channel 1 to move with Channel 2, which on a typical radio is the vertical throw of the right-hand joystick. This means pushing forward on the stick sends the same signal to both outputs on the receiver, so the robot drives forward.

The other mix is to tell Channel 2 to move the opposite of Channel 1, which on a typical radio is the horizontal throw of the joystick. This means if you push stick right, one side of the bot moves forward and the other moves backwards, and is accomplished by setting the mix percentage to be -100 in both directions (do the opposite no matter which direction the stick is moved)

For me, the latter mix – the one outlined in Miku Pink – was NOT responding, despite showing correctly! This meant moving Channel 1 resulted in no opposite motion, just the bot pulling right. This was exactly the behavior seen in the arena, and I would never have discovered it if I had not accidentally put a motor in backwards.

I said the maneuverability tics Clocker showed in its first match will come into play later. I’m now 99% sure that this issue affected the match, and I tried to dynamically drive through it since I try to avoid stationary directional changes (turning in place) due to the brushless drive. A non-working Elevon mix will still kind of work if you move Channel 2 first – it will simply add and subtract Channel 1′s value from one side. In this case, it left the bot prone to pulling right, which is exactly what I saw.

How did I discover this was the problem? Well, I simply had it resend all the settings to the radio without touching a single one and it resolved itself. My radio literally lost a mix from its memory between Friday and Saturday for reasons unknown, even to the point where it convinced its software that the mix was still present.

I must say, I am not even mad. This is an impressive failure mode that I’ve literally never seen before, ever. Before anyone dishes on Hobbyking radios, though, I personally have owned a half-dozen (I keep accidentally giving them to newbies or random students and then getting another one) and also worked with hundreds back in my 2.007 days when they were the radio of choice for the class, and this is the first one I’ve ever seen DROP A SICK MIX like that.

With Clocker out of the tournament and the radio issue solved (!?), I waited for the 30lb rumble to join in on, where I basically overdrove the arm past the end of the gear immediately….. so I simply ran around as a wedge corralling bots in corners until the Vex sprockets’ teeth all came off!

My chain gliders probably wore  enough in that 5 minutes of crazy driving to make the chain skip on the sprocket (since it doesn’t have that great wrap angle), and the power of the brushless drive proceedd to machine the teeth off in short order. Ah well – it was a great rumble anyway. At one point I had every bot except Translationally Inconsistent, who kept slithering away sideways, piled in one corner.

Once I find a good video of it, I shall update the post to include it.

What’s great to see is that the 60A wheels hardly wore. Obviously this is both good and bad, since it means I could have traded hardness for more traction. For the 30lbers, I might go back to the 50A compound – Clocker in previous incarnations has run 50A wheels and I’ve been satisfied. Now is when pouring a few full-size wheels for Overhaul to try and drive around would be a next step.

We part with some shots of gourmet damage from one of Jamison’s loser’s bracket matches against Triggo. megatRON was upgraded to have an AR500 impactor disc on the end instead of a saw, and having that house brought down on you is capable of some serious damage:

this kills the triggo :c

Check out the 1/8″ heat-treated chromoly-steel shell rim also, from the same weapon:

This thing is not trivial; megatRON was actually one of my more feared potential matches because I have relatively weak top side defenses. Expect potentially interesting changes to Sawblaze for #season3 perhaps?!

Speaking of which, what takeaways for Overhaul do we have here besides the obvious bring a spare of the thing you don’t think you need spares of. Or three.

  • DAMN, THAT WAS A GOOD MATCH THOUGH. Honestly, if I had the choice of losing like that to Cobalt, versus the way I did via #setscrewghazi, I’d have picked the former in a hurry. I would have had enough spares to bring Overhaul back online quickly anyway, and it would have made for a much better show and much better test of the bot.
  • I’m highly satisfied with the AR500 wedges. So happy. It deflected the hits from Glasgow Kiss with ease, and also seems to have done its job of transferring the energy into the floor. AR500 has become a bit of a crack epidemic in robot fighting recently as more of it is readily sourced along with laser/waterjet services to handle it. It’s a nice alloy, really – heat treated to the high 40s Rockwell C already, and easy to weld with conventional consumables.
  • Good deflection is also a curse, because you aren’t in control of where the big beating-stick goes afterwards. I’m more convinced than ever – besides by this hit – that the double angle on the front of Overhaul’s pontoons is an absolute necessity. I designed without them for Clocker for simplicity and to see if I’m just being alarmist, but what the single slope let Glasgow Kiss do is deflect its own way upwards and clean house in the clamp actuator. I will need to think about how to  how to retain or improve this design for Overhaul, and to add it to Clocker.
  • I think it might be time for a scoop, for both Clocker and Overhaul. You know how Overhaul has the short arms that I used against Cobalt? Imagine those becoming vestigial and ending behind a angled steel plow which could nest in between the wedges on their inside slopes, making the front of the bot more contiguous. The remnants of this design can be seen in the forward-angled plate that resides on OH1′s forks.
  • It’s more clear than ever that a self-reinforcing geometry trumps material thickness outright. If scaled down directly without changes, Clocker would have 0.75″ thick frame rails, which it clearly doesn’t. It has 0.5″ thick, heavily-machined out side rails with 1/4″ thick cross-bracing plates, and that left the match against Glasgow Kiss needing a single screw extraction and maybe a hit from a good ol’ Engineering Hammer. What this actually means is I spent much of the 6 hour drive back from Harrisburg trying to rationalize that maybe I do need to have Overhaul’s frame remachined again. I’d be able to optimize for the geometry of the side rails. It would shed a lot of weight which can go into other systems I was running out of weight for, and really, based on how deeply Overhaul’s frame rails are pocketed, it’s almost useless to be made from 1.5″ thick stock. But UUUUUUUUGGGGGGGGGGHHHHHHHHHHHH.
  • I’m really, really itching to leave the clamp collars behind when it comes to power transmission to the forks. I think when it comes to fork improvements, just adding cross-bracing to Overhaul is enough, and I way more favor the 8-bolts-to-remove-an-arm setup on it right now for serviceability. I can replace a full set of arms and the clamp actuator on Overhaul faster than I could get the damaged forks off Clocker.

I would love the opportunity to test these hypotheses on a 30lb scale again in less than 1 year, especially because I (think) #season3 is still going down this year. Even if I can’t prove my hypotheses in short order, this was all good stuff to know!

It’s Motorama 2017 Time! Überclocker Changes and Upgrades

Feb 15, 2017 in Bots, Events, Überclocker 4

Since Franklin Institute this past year, I’ve been spending quite some time thinking about what changes I need to make to Überclocker for the annual winter robot party, Motorama. It’s the largest event on the east coast for years running, and the ONLY one left with full-contact 30lbers; I’ve gone basically every year since 2013, and sporadically before that (2008, 2010). This year is slated to be some kind of BattleBots #season2 reunion (where Season 2 was called “Motorama, the TV Show” since so many builders who regularly participate ended up on teams!), and there are some of us who are taking the opportunity to do some… scale model testing. Quick! What is the Reynolds Number of a flying Tombstone!?

So here’s what has been going on during the past few weeks! In my summary of the Franklin event, I identified a couple of strategic issues with Clocker which would also concern Overhaul for #season3, given that they’re built so alike.

The first was having everything ‘line up’ in the front. While it also included making the pontoons more adjustable, higher priority on my mind was making sure the arms have enough constraint that they don’t just splay out. We saw this happen in the Overhaul vs. Beta match where I caught Beta with one arm over and one arm under, so the arms because angularly misaligned. Recall that Clocker 3 and before all have multiple spanning elements holding the forks together; alignment was never a problem with that, but Overhaul didn’t have those elements primarily for an aesthetic reason (to maximize the forkiness). While Clocker sort of did have those constraints at Franklin, it was just one spacer stack, and that was quickly lopped off by megatRON.

 

So I’m gonna add more, duh! These two additional spacer & tie rod stacks are located out-of-plane with the one at the end, which will yield much greater torsional stiffness.

One issue is that another 18″ of threaded rods and aluminum tubes will put the bot back overweight a few ounces. Nonetheless, I intend to just build everything out to my desires, and then try to weight-cut from there, rather than compromising early. To pre-compensate a little, I decided to order replacement smaller drive motors. The AXi motors are great, but they are dramatically overkill for power, and I can definitely afford to lose a few ounces. Going to the 42mm outrunners will save me about 3 ounces a side, which alone might be enough. In order to utilize the smaller, higher-Kv motors, I also decided to order a pair of Banebots P60s in the 4:1 ratio instead of my current 3:1s, which should allow me to keep about the same speed.

Now, the 2nd big strategic weakness I want to experiment with is where it gets a little interesting.

I mentioned in the FI post about minimizing my defensive cross-section when it comes to vertical weapons. Those things – including drums, drumlet-drumettes (smaller in diameter and width) and vertical discs/blades are actually what I fear the most designwise, because they do two things to you in a match. One is flip your bot over, from which you need to recover (and which would take precious seconds where you’re vulnerable to followup attack from a good driver), but the more insidious one is ruining any straight edges you might have had where the weapon hits. A small KE weapon will put all of its energy into your material like a singularity; it will deform wedges and protrusions, basically preventing you from having an advantage again. All it takes it one fuckup, as Clocker’s match with Duck Yeah and even better example Blacksmith vs. Minotaur show. Notice how Blacksmith more or less has control of the match before it gets dinged once.

So to counter these kinds of weapons, you would have to do two things. Number one is keep them away from you, and number two is present as small of an area for them to touch you in as possible. There’s a lot of precedent in the sport with “keep away sticks”, including one used to great effect on Icewave last time on the show. To reduce my “vulnerable edge length”, then, I basically had to distill the front wedges down to points.

I take that back: this got interesting very quickly.

 


DUAL WIELD

So that’s revision 1 of the design. See those perforations? That’s for if I mess up and somehow manage to plant these into someone’s weapon instead of besides it. This design is intended to be cut out of AR500 grade steel, which is extremely rigid and springy but won’t stretch that much, so it will preferentially break at the postage stamp line. It’s like an active salamander tail system.

The saw teeth on top are the real bad idea here. Instead of a keepaway stick, I wondered what would happen if I made it a part of the offensive strategy. Most of these little vertical weapons have rubber belts attaching them to their motors. What if I just went straight for that with a very sharp stick? Stab into the gap between weapon and robot frame until you damage the belt or take it right off. That would take some serious driving and luck to pull off, which lured me to the idea further.

There was only one thing I didn’t like, and it was one of those “come back to what you CADed up last night in the morning and think again”. One of my complaints in the FI recap was getting stuck on MegatRON when we charged at each other. These extra-long death-shanks are attached just as the pontoons are, so if I run up on someone else’s wedge I can just as easily prevent Clocker from getting back off. Which is serious bad news when it comes to avoiding a vertical disc/drum spinner, since now they can just turn slightly for a broadside.

This led to revision 2:

Yeah. “It looks like a sawfish-unicorn”, or an Overwhal. That’s right, I decided to affix it to the clamp arm instead, exactly in the fashion shown.

This position I liked a whole lot better for two reasons. One is that it’s implicitly height-adjustable, and can actually be a manipulator weapon of its own. Clocker’s top clamp arm is not trivial – it is designed and built for about 500-600 pounds of closing force. It will lift a lot of things on its own, and is more finely positionable than the lower forks. It’s also more durable with its leadscrew attachment, but the leadscrew anchor is also a mechanical fuse for if things go very wrong and it gets the uppercut treatment – it will break away and probably fling the clamp arm backwards and out of the way, leaving the forks still usable. If I attached this to the forks, and they get bent, then my life becomes very difficult.

The second is a takeoff from the height adjustability. I realized that offensive unicorn strategy #2 was that now I can reach around weapons and bring the house down on their retreating sides, where the disc necessarily disappears back into the robot. With crafty positioning (or a lot of flailing) I could pretty easily literally throw a wrench in the works and shove a wad of AR500 directly between the robot and its own weapon. This would probably result in a very sad unicorn horn and ideally more sad opponent; for me, that’s why the postage stamp holes are kept, so not only will it break away on a successful landing, but will also do it and leave me a 2nd chance if I miss.

Strategically now, I can keep the clamp arm closed and all the way down and use the horn as a keep-away stick of minimum attackable cross section, and also manipulate bots from afar, or get it caught in something else like exposed drive wheels.

….and if you thought it looks silly in the CAD, it looks 10 times as silly in real life. I actually want to make another one of a different length now!

This is another ‘attachment of several ounces’ which would necessitate shedding weight elsewhere, which I will find. One thing I designed up previously but never implemented in real life was a set of light wedges, to be made of sheet 1/8″ aluminum bent into shape. I’m going to go ahead and make them, since they’ll cut around 1 pound off the bot each (Those steel wedges are HEAVY!)

I won’t need that much reduction in weight to use the horn of course, so maybe the configuration will add something else interesting to make up the weight, or just ballast. There is literally no point in weighing less than 30.00 pounds.

So that does it for major design changes. Moving onto more minor quibbles, I wanted to go back and have a look at the wheels again. The custom 50A cast urethane wheels worked beautifully at Franklin, and I now had a bucket of Simpact 60 and Forsch URS-2160 (McMaster part number 8644K24), both 60A urethanes with much higher tear strength ratings, to try.

Now that I was confident in the process, I revisited the hub design. I just designed the first hubs with circular thru-holes for rubber retainment so they could print without support, but the circular holes caused the diameter of the hub to start getting large. I didn’t have much more than the 1/8″ tread pattern’s worth of tread thickness per wheel. With a more rigid rubber, I might be able to increase the relative thickness of the tread portion.

I updated the hub to look pretty much like a scooter or skate wheel core – through-slots replace the circular holes, and the walls are thinner. This brought inwards the OD about 1/4″, which is great!

I also wanted to play with another tire geometry. A little earlier in the year, when Big Chuck’s Robot Warehouse was just being set up, we rented a floor grinder to strip the wooden floor of the decades of industrial grunge that had set up colonies within it:

Well gee, as soon as I saw that, how could I not clone the design in one of my own wheels? So if you’ve never used a floor grinder, a big sanding drum gets shoved over this flappy-wheel. To install it, you lock the rotation of the flappy-wheel and gently rotate the drum over it (in thise case, clockwise) while pushing it on. The flappy-wheel is effectively a huge sprag clutch with the drum as the outer race and the flaps as the ratchets/sprags. When the wheel is spun by the motor and the drum gets loaded against a floor, the flaps get forced open a little from the transmitted force of friction, causing them to push out against the drum harder, which causes more friction.

After I finished going “Well huh, that’s kinda smart’ I realized this design would get very good traction in one direction as each flap gets forcibly planted into the arena floor. The reverse direction might not be as spectacualr. Before I got ahead of myself with anisotropic traction designs, I decided to just imitate the flappiness  in my current tire design.

That’s the same helical tread sweep, just with many more slits of a greater depth and narrower width. I did this for “easy” (change the number and size of swept features) for the time being. I’d like to play with a straight-cut geometry like the floor scrubber in the future.

Printing this damn thing was an ordeal. Unlike the previous wheels, the molds could no longer be printed upright without support structures due to the way the helical threads are placed. Furthermore, the deeper tread features also prevent demolding in two halves, so I had to split the mold into quarters. Attempt #1 with supports was basically a no-go, since it was almost impossible to get them out cleanly and not leave little strands and hairs everywhere.

I next tried to print the mold wedges “pointy side up”, making a flat face on the outside of the circle for them to sit on. This was okay, but the nylon warped just enough on each print to make the edges not seal at all – this was attempts #2 and #3. I guess I could have made an Onyx mold too, since it has virtually no deflection, but by that time I’d mentally moved on.

The fourth and successful attempt was a single-piece mold which simply had the upper lip chopped off. I don’t even know why I thought the upper lip was needed now. Just fill to the top and be done!

That’s the model with the lip removed.

So how do you demold this damn thing? It was risky, but I decided the one-piece mold was okay because of the spiral nature of the tread allowed me to helically demold the cured wheel from the mold. And this ended up being completely true! I back out the hex bushing a half-inch, take a wrench, and untighten the wheel right out!

This worked quite well. Here are the two first wheels to emerge with the new material and tread! I stuffed the leftover mixed rubber into an old wheel/hub combination, because wheels are wheels. Notice the white core of the two new ones – they’re made from plain ABS, since I wasn’t about to waste the Onyx material on something I wasn’t sure could ever be removed from the mold. They’ll be on standby as low-priority spares nontheless.

Next up, the Forsch Polymers URS-5160. Forsch is one of those “Call Billy” companies that I always complain about – just go look at their 1997-chic website! Except this time, I was literally told that I had to call Billy (over in BILLING no less) and FAX him the order, then MAIL them a check. Credit card? Paypal? Pffff.       

Oh, Billy also leaves at 2pm each day, so I gave up after 3 days of failing to get in contact with him because I might have trouble waking up before 2pm on most days. Luckily, someone clued me in that McMaster’s general purpose pourable 60A urethane is manufactured by Forsch, otherwise I would have given up completely.

So why the hunt for a product which tries so desperately to not be purchased by anyone? Well, it advertises around 25% more tear strength and ultimate tensile strength than Smooth-on’s Simpact 60. Smooth-on is geared towards being easy to use – everything is made 1:1 or 1:2 mix ratios, so it doubtlessly sacrifies some strength and performance for convenience. I figured that polyurethanes worked like tacos – the shadier and harder to find that a Mexican restuarant is, the better the food. This has been almost bulletproof in my experience. I made it a point to obtain a Forsch product and use it like Robot Jesus Himself intended.

What I really want to try getting my hands on is the URS-2450, which has basically the same tear strength but in a 50A durometer. May Billy and I finally meet in the grand arena of procurement soon.

I cut new wedges out from AR500 plate. These were what they were meant to be, but I couldn’t get the material in 1/8″ (or 4mm-ish) thickness in time before Franklin. This was actually cut from one of Jamison’s spare plates left over from Sawblaze. I’m preparing them for welding here by grinding the incredibly thick scale they all seem to come with off.

Stay tuned for more, though with Motorama now 2 days away, I might just be updating after the fact! Still to come are the making of the pontoons, the spare lighter drive motors, and maybe a little bit of wheel testing!

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

Feb 09, 2017 in Bots, Events, Twelve O'Clocker

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

Oct 21, 2016 in Events, Überclocker 4

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)