Archive for the 'Project Build Reports' Category

 

Überclocker 5.0: The Big Post of Designy-Stuff

Dec 07, 2019 in Überclocker 5.0 - 30Haul

Alright! So previously I established some of the bot’s principal geometry. Now I had to actually import more components and try to flesh it out, and make little edits here and there. Recall this was where I ended before:

I’d already tabled the idea of moving the clamp motor to the arm tower region, and the lift motor has been moved slightly forward and under the lift gear. This had the side effect of pushing the drive motor (and hence the front wheels) rearward a good half inch or so, and I was a little dubious on if the bot would have weight far enough towards the rear to lift anything.

The clamp arm (the “head” as everyone calls it) was going to stay identical to the previous 30Haul version; I already had parts to fit it, and so it didn’t make too much sense to change. This was, after all, an exercise to see if I could keep a lot of Overhaul 2.x parts the same when it comes to the liftgear. So far, I think I can keep the entire top half of the bot using the same parts, so it will save a ton of redesign effort.

I’m now continuing to flesh out geometry and adding more critical (but blank) parts. The lift gear was going to grow some compared to last 30Haul, to give it more of a ratio with the lift gear. I had a plan this time of running a 3-stage P61 gearbox and using a single larger output stage, in order to be a little more commensurate with the old DeWalt-based lifter which was a 52:1 ratio with a roughly 4:1 output stage. The plan here was for a 45:1 P61 with 5:1 on the main lift gears. The motor shaft would stick through the left frame rail some, so the plan was to put an outboard bearing in to greatly reduce the bending burden that the narrow, necked P6x shaft would have to take otherwise; that’s what the large clearance hole where the lifter gear should go is for.

The intermediate vertical bulkhead from before has been turned into a kind of quasi-bottom-plate made of the same thickness material. All 3 motors bolt to this plate with spacers between them and the plate.

I’ve fully fleshed out the drive system here (all…6 parts of it) and given more detail to the lift assembly, including generation of the arm towers which are hidden in this view.

The Wall of Wub positioning was going to be two large groupings on either side to accommodate the legs Uberclocker is known for (which turned into the wedge pontoons on Overhaul). I also made volume claims for the center shock mounts when 30Haul gets its very own DETHPLOW.

I just imported a 30haul old arm in for geometry and visualization purposes. At this point, the bot’s CG was already very close to exceeding the front wheel line (a.k.a it’ll always tip forward). The height change of the main lift axle meant the forks themselves had to be shorter with a more severe curve. I decided to start over instead of trying to change the geometry of the existing arms, because there was something else I wanted to try.

One of my perceived flaws of the Overhaul lifter fork design is they’re still rather wide at the tips. I wanted the lateral rigidity there, but it did mean if the arm tip got bent up it was hard to get under someone with it ever again.

My bright idea for 30Haul, which would be equally reproducible for Overhaul, is to have a main plate member that is extra thick and rigid, but only have its thickness sticking out as the attack interface. Something set a little more inboard can provide the overall side to side rigidity.

For 30haul, this meant I was actually going to make each fork from a solid backbone of 1/2″ aluminum. We start with the basic dropdown shape which will clear the frame. I made some push and pull adjustments as I went, since I wanted the arms to descend down quickly, but shouldn’t cut away too much of the front frame rail.

The upper curve is generated with some tangent arcs.

And the bottom curve just follows the same arc center with some more edgy features. This is actually how Overhaul 2.x forks were all generated too!

I smoothed things out and added some thru-spacer holes as well as bolt circles.

Check out that arc of 5 holes that runs roughly down the length of the arc shape.  This is what they’re for:

Instead of discrete standoffs like last 30Haul, I’m going to be using a single solid plastic spacer between the inner and outer fork. The discrete spacers were fine for 30lb Sportsman’s Class duty. But they just entered Full Dab mode under any significant side impact since the standoff thru-bolts provided bending axes!

The idea of this fork is the thinner reinforcement plate and the thicker main plate are supported full-contact with the rigid plastic insert. Hopefully, this means it will act substantially like a sandwich composite in that side bending regime, and maybe a hard smack from a weapon will introduce a bend or a bow, but it won’t just completely fold up.

I was planning on using the Markforged machines to print the center spacers in Onyx, but they could also be cut from solid plastic.

 

After specifying and adding the inter-arm spacers, the majority of the bot’s mechanical needs are done now. Seriously, there’s so little going on compared to one of my average designs.  It’s kind of a refreshing change, honestly.

I next moved onto making the basic support legs that enable the bot to grab and lift. These front legs had to be Sportsman’s Class rules compliant first, which is why I’m going for a simple fork tine-like projection instead of the crazy angled wedges.

I started with the sketch plane that’s defined off the thickness of the rubber shock mounts, and made a big plate which covers all of them.

I had a change of heart at this stage, and instead of making solid projections that altogether ride on the wubbie mounts, I decided to pursue a hinged design.

I always thought I could preload Overhaul’s wedges into the ground with carefully adjusting spacers/washers on the wubbies. Yes, I technically could, but they then weren’t far from a permanent setting anyway. I found that the previous 30Haul only exhibited a narrow range of satisfactory wedging versus propping its own front wheels off the ground.

Hinged wedges have been on the retreat in the sport for a while (albeit slowly) because of their vulnerability to getting damaged. But a lot of bots still sport them, because having something load itself into the ground with its own gravity beats you carefully applying a pre-determined force trying to do the same in an environment that can throw anything at you, at any time.

The legs themselves will be made from thick aluminum also, for this time. They’ll be allowed to hinge upwards about 10 degrees – something can get under them without consequence as long as I back off in time. Even a fixed-but-compliant  wedge would, in that circumstance, still cause the bot to lose traction in the front if lifted.

I just drew some lines that looked cool first and foremost before making the geometry compatible.

Here’s what that assembly looks like up front. Now, it IS true that having hinged elements that are also on wubbie mounts is superfluous, and I agree. If the wubbies proved to add just too much extra compliance, I was satisfied with running plastic spacers underneath for Franklin and Robot Ruckus.

A size comparison between Clockers 4 and 5 (a.k.a first 30haul and new 30haul). The new bot is shorter by a bit – maaaaaaaaaaaaaaybe even too short on the wheelbase. But it’s not outlandishly compact like I worried about going in.

Before I started on the electronics layout, I decided to put the finishing fastening detail touches on the mechanical end – Every hole got at least one sample fastener as a sanity check, and I also laid out top and bottom plate bolt patterns.

 

Up until this point, I’d actually never designed the rear idler hub. I modeled it as kind of a top-hat shaped spacer with two shoulders, one for the wheel hub bearings and the other to space it out from the frame. It would just get anchored in with an extra-long frame rail screw after the wheel is mounted.  Relatively simple and durable!

I also decided to knock off a few BB entry trends and add “breadboard holes” to the frame. Some on the sides,  as can be seen, but mostly on the back.

The idea of these breadboard holes is to be able to add attachments and defenses in a quick, reasonably strong way. You standardize on your own bolt pattern when designing these accessories. I didn’t have any in mind at the time, but it’s one of those “Boy, it’ll be annoying to drill them later” features.

 

The clamp actuator was imported from Uberclocker v4 and is almost completely unmodified except for a total height trim right next to the three small mounting holes. There was just a lot of unnecessary material here before, and this allows the actuator to be about as compact as I can get  it.

So that’s about it, mechanically, for the bot. I’m definitely not used to something having this few parts, and I really hope the design approach works for Overhaul proper.

With this allowed to rest for a while, I turned my attention to “things which hold electronics”.

I’m reusing the design of the battery tray from Uberclocker 4 with a few small geometry shifts to accommodate the frame shape of this bot. It has slots underneath where hook-and-loop cinching straps get fed through, which hold the battery down.

The “Rage-hutches” as I call them each hold two 6-FET Brushless Rages face to face stacked vertically. I found this was a convenient height – just barely under the thickness of the frame!  They’re made of 2 pieces each. One is a baseplate with mounting ears, and the other is the perimeter “U” shape with holes and reliefs for the heat sinks.

In another deviation from my usual form that I want to point out is the utter lack of small hardware on the bot now. The top and bottom plates are retained by 1/4″-20 thread size, and even the electronics mounts get 1/4″ compatible clearance holes for a nut-and-bolt interface with the bottom plate.

I’ve tended to use #4 screws – or at least very small screws – to hold ancillary parts and electronics in. One of the critical exercises we did for the company products was really trying to standardize on hardware, and after being part of that, I am keeping in mind the number and types of fasteners in use in the bot. A long time ago, most everything I made robot-wise was just using whatever hardware conveniently fit the geometry…which meant I might have needed 4 different hex wrenches to change a motor, for instance.

Working  on deployable products, plus the much higher regimentation requirements of the BattleBots pits if you actually wanted to get things done fast, have made me think of all this from the start. This bot should be serviceable for the most part with a 5/32″ hex wrench. I actually spec’d button head 1/4-20 (frame and top/bottom plate) but regular socket head #10 screws (motor mounts) because they share the 5/32″ drive. I made more use of #8-32 than I ever have before as my “small screw”, because Vex parts are made for 8-32.

And here’s the size comparison again from the top view. I was fully expecting Uberclocker 5 to not be able to drive without the opponent raised very high. Overhaul 2.x and Uberclocker v4 both have substantial front traction in the form of small wheels located nearer the center of lift. Other things of note – the inner frame rails of Uberclocker 4 are about the same width as the “Outer” ones of v5. The attacking cross-section of the bot remains much the same in terms of width and height. Really it’s those big Vex wheels that sort of make the thing look small, in my mind – the body looks visually smaller in comparison to the large wheels that poke out.

From the side, the bot has gained some height, but pretty much solely due to the added chassis height. I was able to keep the curvature of the fork tips not too severe – the taller they are, the harder it will be to grab opponents.

Overhaul 3 itself should still have a somewhat longer wheelbase and better proportions of the wheelbase x track rectangle. Remember, I had to move the front wheels backwards. By the original design, they should be very close to the front transverse frame rail.

I personally felt, too, the bot could have stood to be a bit longer even here. But, it really couldn’t get longer. Why?

If the bot went further back, the thing wouldn’t really be able to self right. I’m sure it can throw itself back over with the momentum of the lifting assembly, but I like being deterministic from the start. This was a length restriction for Overhaul 2.x also – in one swing of the forks, I had to be able to tip the bot onto its wheels again. So this means Overhaul 3 is going to have to gain wheelbase, If I so desired, by moving the front wheels forward again to where I intended them.

Next up, the initial rounds of fabrication begin!

The Overhaul of the Future Begins Now: Überclocker 5.0 (Also, Welcome Back to Robots)

Dec 04, 2019 in Overhaul 3, Überclocker 5.0 - 30Haul

After season 2, I had a whole list of changes I wanted to make and “design regrets” …that I wanted to address.

Really, I… see #season3 as a chance to do Season 2 “correctly”, addressing things that didn’t go the way we want or designs that could have been done better.

And frankly, anybody trying to build from scratch for the season now is either a dumbass or more of a man than I…

-me, some time in 2018

 

AAAAAAAAAAAAAAHHHHHHHHHHHHH

Those words have come back to haunt me.  Great! That’s totally never happened before, right? 

Okay, okay. No more vans, I promise – not for a while, as the Cold Brutal Winter of I Hate New England Weather has fully settled in. Here we are, on the cusp of another potential (#NextWeek) BattleBots season. I still owe the world a “event report” and summary for BattleBots Season 4/2019, which I went to anyway and set up in the pits as a Ragebridge dealer.  While I obviously didn’t bring Overhaul nor was involved in any of the matches, I did get up to a lot of Learnin’ and Talkin’ to with everybody there, as well as some incidental brushless motor troubleshooting. I tell you what, kids: brushless motors are a mistake.

My takeaway from the whole two weeks of hanging out with everyone, watching all the matches, and being in the pits acting sporadically helpful or like a nuisance? The metagame has moved on, and Overhaul has to move on with it. Consider this post really a recap of all of the off-season work since then, up until a few weeks ago which I’ll cover more in detail as this post series grows. Sit down, because it’s gonna be long and filled with Philosoraptor Charles Mangst!

The Exposition

Coming out of Season 3 in 2018, I was actually very satisfied with the bot mechanically. Here’s what that entails:

  • The Fantastic Combination Gearnut and packaging of the clamp actuator was greatly improved over the Season 2 ball screw design, and it worked swell the entire time. This part – and really the entire updated clamp arm for S3 – is probably going to make a straight unedited return.
  • The frame brace that was added to the intersection between the outer rails and the front crossing bulkhead greatly increased the rigidity of that area, to the point where there’s no visible deflection even after getting thrown around by Witch Doctor and Warhawk.  To be fair, OH got some reasonably softball matches that season, and I’d love to see just how it would have done in another old-Cobalt style hit. But it truly was a hack to try and patch a deficiency in the original design.
  • I was super into the redesign of the main lift hub, which was really my first on-purpose designed hollow weldment with attachment features. It  had a larger radius of engagement (bolt circle) with the lower forks, and enabled the forks themselves to be a single design instead of having 2 mirrored configurations.
  • The cast wheels and drivetrain proved also reasonable in service. The front wheels ended up being a little too fragile and had to be replaced almost every match, but I didn’t have any SET SCREW PROBLEMS this time at least. In all, even during Season 2, the drivetrain of the bot hasn’t been a source of mechanical headache – remember in S2 I drove the entire 3 minutes, even if underwhelmingly, against Beta, and this time around barring fire issues Overhaul was in pretty constant motion the entire time.

So in summary? I did get to do “Season 2 correctly” in that limited sense. But obviously, the whole bot catching on fire issue was…. suboptimal, among other emerging and now very salient problems.

The Conflict

So did I REALLY “do Season 3 correctly” either?

Brushless Rage was tested on the bench under some simulated use cases including throwing big hub motors around. But what I wasn’t able to make time for was actually putting the system in the bots, including Sadbot, and then driving it around enough to discover the transients that would ultimately cost it matches. The development of Brushless Rage took some of 2016 and 2017 while first I was kept busy at the (then) new shop space doing consulting work, and then the startup itself ramped up significantly closer to the back half of 2017 and going into 2018. 6-FET Brushless Rage has, by now, proven itself to be rock solid in the lighter weight classes, but I could not test 12-FET to discover its limits effectively.

Not that I’m blaming it exclusively, mind you: a few other bots including Brutus and Predator actually ran it fine for multiple matches during the season. Instead, in light of some new testing performed recently with Sadbot and Overhaul itself, which I’ll discuss here in the near future, I’m rather convinced that the interaction between Overhaul’s split drive motors (i.e. two ganged motors per side) was what led to my FIERY DEATH! problems.

Here’s what is going on in the Overhaul 2.x drivetrain. I have two 63mm brushless SK3 motors per side, each going into a Banebots P80 gearbox that’s a single stage 4:1, and the outputs joined by a short chain.

Seems legit, right? The problem is, if you hold one motor still, you can just about rotate the other motor a half or even 3/4 of a turn before the slop (made of two 4:1 derp-tier gearboxes and a kind of loose chain) is taken up and you actually “feel” the other motor.

The problem comes when direction changes and stops occur. No ESC is ever perfectly timed, and no R/C pulsewidth is noise-free. Nor can you guarantee the motor stops in a useful position to quickly push the other way.  Therefore, the chances are high that in stopping and direction changes, one motor acts first – and promptly runs into the other, possibly desynchronizing with the ESC momentarily too. When this happens with a brushless setup, you usually get high surge currents for that instant. Add up enough of them and I can pretty easily see the Brushless Rages simply overcooking themselves in under 3 minutes.

It took driving Overhaul hard around the expanses of the new shop which the company moved to only this past March, with the lid off, before I was able to witness this in action: some times, one motor will just start before the other on the same side. Before then, I’d never been up close to the bot as it was rapidly changing direction, turning, or stopping (…for good reason, I maintain). All because the old shop was too small and confined to safely do it, and the lack of ground level access and dismal state of the parking lot anyway meant the psychological need wasn’t there. It “drove fine” in the limited context of the shop floor, so I hoped for the best.

The original premise of this design was to load-share the 6374 motors, which definitely have adequate power output ability to drive a heavyweight around on only two, but which do not have nearly the thermal mass needed. Work done is still work, and the same amount of energy heating up a smaller mass makes it much hotter.

But in retrospect – and only can I really say in retrospect now because others have done it as an offshoot or variation on this design – the way to do it would have been to gang the motors together themselves, instead of through gearboxes. The Robot Wars entry Magnetar (and Pulsar) built by contemporary Brushless Hipster Ellis in the UK illustrates this: two 63mm brushless motors are ganged onto a single bull gear directly. There’s minimal slop between the two, virtually eliminating the chance of the motors contesting each other.

I’m not gonna write the OH2.x design off as “too complicated” – really, the mechanicals of the thing never gave us any problems in the pits. It was designed to allow quick disassembly of the frame rails and replacement of wheels, and it fulfilled that role well. We never had spontaneous chain-falling-off or wheel-jams-up issues like so many bots did (…minus #SetscrewGhazi). What I chalk it up to be is a 2nd-order phenomenon (slop between motors) that interacted very poorly with the control architecture (dumb R/C-style sensorless commutation) and whose cumulative effects (overheating and failure of one or both controllers) were not discovered due to lack of stress testing.

And I stuck with it for 2 BattleBots seasons – one because I didn’t know better at the time, and the next because I didn’t really have the time to deep-dive into these assumptions. As for why Overhaul didn’t catch fire during the regular Season 2 matches? Well, remember the 3-way “MIT Rumble” at the end. It did consume one of the dLux ESCs, and it was a match where I was much more involved in pushing and shoving and trying to flip Road Rash back over. In the Cobalt match, #SetScrewGhazi ended the match early. And I spent most of the Beta match running away from it!

I don’t know how much it all mattered in the end anyway, because the fact of the matter is: I never liked how Overhaul 2.x drove. Not with Colsons, and not with the urethane cast wheels.

Here’s the plight I face. Everyone plays me up to be a “good driver” because of my historical wins and my usually more showy driving style. I’ve never been able to bring it to bear on the TV show. It hurts to watch OH2.x matches, and believe it, it was even worse physically being up there. Unlike Overhaul 1, and by derivation Sadbot, OH2.x seemed sluggish to respond to inputs despite being – or maybe BECAUSE OF being – overpowered drive horsepower wise. I never felt one able to put the power into the box floor. Missed charges, lost or parried pushing matches, and just plain to-the-audience questionable maneuvering were all symptoms. Like just go back and watch Overhaul 1 and Bite Force 1 again. I live for driving matches like that, and OH2.x has not been able to follow through.

Remember the Sadbot driving video I linked above? The difference between doing that with Sadbot and trying to do it with Overhaul 2.x is, at all moments in that video I felt like I was in full control of Sadbot. With Overhaul, similar attempts this year felt stiffer, and the bot was less able to effect turns predictably – even after all of my arena time with it, on a bare polished concrete warehouse floor, I found myself going “Wow, this thing drives like garbage”.


If I actually ran this match, I’m fairly positive in Sadbot being able to win 100% of the time.

 

Part of it is geometry. Overhaul 2.x has a square drivetrain layout, where Overhaul 1 rested mostly on its front 2 wheels with a wheel arrangement that is much wider (track) than long (wheelbase).  Sadbot, using the same drive system but with a very central weight bias, handles even better. A slightly oversquare (wider than long) drive will be more favorable to quick turns and controllable slides, whereas a longer-than-wide setup is going to favor a more point-and-shoot driving approach where you tend to separate turning and forward-backward driving into more discrete events.

The other part of it, as we mused over in the pits at Season 4, is just sheer contact area. Academically speaking, no robot should ever have a traction advantage over the other except as a function of wheel compound softness. Because hey, Fₜ = μFₙ right? That’s how it’s presented math-wise in robot land, and is how must physics students learn about friction. And if both bots weigh 250 pounds, the vernacular rule of thumb always goes “softer tires win because the same weight will press downwards no matter how much contact patch there is”. Go ahead – ask a question on any robot builder group if treaded wheels are “better” than slick wheels.

What I think the basic theoretical treatment misses on is how dynamic forces from robot motion, wheel compliance, and weight shifting affect both contact patch and resultant available friction force. Think of it this way: A small and relatively stiff wheel like a Colson will never really change its contact properties with the arena floor no matter what angle you mash it into the floor at. It’s going to be tiny relative to the total wheel circumferential area, and vaguely parabolic or elliptical-looking.

However, a big go-kart tire, despite being made from a “harder” rubber compound, is designed to deflect and comply with the ground. A solid foam tire might be somewhere in the middle, offering more stiffness except when you really are putting power into it, deforming the foam carcass. What it means on a high level is that the contact properties with the floor exhibit a very wide variation with the potential for simply more favorable solutions to transmitting the total available drive power of a bot to the ground. I can’t really substantiate this without writing an entire thesis on it, but a gaggle of robot nerds petting each others’ confirmation bias is at least 80% as reliable!

In other words, what a few of us pretty much concluded from the mutual chin-cupping and nodding of this season was that if you wanted a quick yet maneuverable bot, you pretty much had no choice but to use acres and acres of tires. Compliant, bouncy tires, of almost any compound and material. The most stupendously driving bots in the game – designs like Stinger/Sewer Snake, Hypershock, Free Shipping, Sawblaze, etc. all just have obnoxious amount of wheel – go look at their official bot photos.

Too much wheel for me, historically speaking. I grew up on the romance of graceful, low profile bots like the original Biohazard, and this has carried over in some way for almost all of my robot bloodlines. Even Overhaul 2.0 was, in a way, a romantic testament to the low-slung billet-machined box.  Take the top half of Overhaul off, and it’s just as nice looking as a flat lifter-box style of bot from the Classic Days. In fact, at one point, I was going to run “just the bottom” as a Middleweight at RoboGames.

That preference, I realized, also comes back to bite me when it comes to driveability. Small, rigid wheels are better suited for the point-and-shoot bots because their inflexibility also means their regime of best tractive performance is more limited.  My general feeling is that the custom cast urethane wheels with tread lines made OH2.x traction more linear and predictable, due to being able to clear box floor debris, but not necessarily any greater in magnitude. It was, at least, consistently bad to drive and I felt like I was able to somewhat work against it – but put me in a match where the opponent had Acres of Tire such as Sawblaze and even Witch Doctor at the end of Season 3, and the difference became stark.

In short, the 6 rigid and small wheels of Overhaul 2.x were not conducive to it handling predictably due to so many points of contact on a varying floor, and just not having the deformable contact patch to really transmit the power of the drivetrain into the ground, at least without overcoming the material’s own shear strength.

There was one final trend that bugged me to see in Overhaul 2.x that stemmed from its last 2 matches with Witch Doctor and Warhawk.

Even if I can self-right, the ability to get away quickly to do that somewhere else is absolutely critical.

Yes, Overhaul can self-right. It can even do so pretty quickly, but some times the bot needs a second or two to settle into the position, especially if the clamp is all the way extended. The ears actually help with this explicitly; on Overhaul 1 they were 100% critical to self-righting at all.

But, that second  will kill you because Bite Force can get the good ol’ one-two hit in. That’s the nice thing about little vertical spinners – you can just keep pointing yourself at the opponent and expect results. Again, look at the most legendary driving bots of today: they can drive in almost any position, even if not on all wheels, at least enough to get themselves out of a sticky situation. Overhaul 2.x can’t do that, and not even Overhaul 1 or Sadbot can.

In the end, if I wanted Overhaul to drive like Hypershock, so like Hypershock it must appear. I was going to have to dispsense with the romance of Biohazards Past and focus the bot’s geometry on being able to drive. I know, now, that it can grab and lift just fine. But no amount of high-performance grabby-lifty will win matches if you can’t feed the opponent in.

Personally, I wouldn’t be convinced at this point that I “do a season correctly” until Overhaul just gets out-robotted consistently. Losing repeatedly due to random mechanical and electrical bugs is just sloppy.

The Dénouement

As OPERATION RESTORING BROWN was ongoing, a lot of these newly updated design requirements were stirring in my mind. It’s what I was actually doing while brainlessly covering myself in “van powder”.  I wanted to get a new Überclocker (/30haul) together for Dragon Con, but let’s be real, van is already too much of a project anyway. The next best thing to aim for was NERC Franklin Institute in October, or the Orlando Maker Faire “Robot Ruckus” in early November after I get back from Dragon Con.

Basically, while I was destroying my brain cells painting the van cab, I was using the remaining few I had left to formulate what I wanted out of Überclocker v5 as a Robot Reynolds Number test model for Overhaul 3.

  • As I mentioned, the lift and clamp arrangement was going to remain unchanged. This goes for Clocker too – even V4 (with Overhaul 2.0′s general appearance) managed to get off some great throws, and I was familiar with the design needs of the leadscrew drive clamp and gear-drive forks.
  • It needed comically large wheels for its size. Mentally, I figured Overhaul was going to use a go-kart tire or foam-filled utility tire in the 8 to 10 inch range, so it implied a 4 inch and up wheel.
  • However, and this is the important part – I needed the wheels to at least behave, on the 30lb scale, like what a foam filled or solid foam tire would behave at the 250lb scale: fairly bouncy and compliant. This actually ruled out a lot of wheel and tire choices. I could get the 4 inch BaneBots wheels again which Clocker v3 used to amazing effect, but they are fairly rigid. Same with Colsons. Custom-cast silicone or urethane wheels with a durometer of 30A or so might have given me that compliance, but from my experience casting soft urethane wheels for Clocker v4 at Franklin Institute, they were also going to shred and burn out very fast.
  • The design had to accommodate what I called “butt traction”. Overhaul, and by extension Clocker v4, can’t get tilted backwards more than about 25 to 30 degrees before all the wheels are off the ground. Even Clocker v3 has “butt traction” ability – see how the rear wheels extend past the rear frame members? This is suboptimal from an armoring perspective, since a spinner can pretty easily pinch your wheels off from the back. But a part of me wondered if that was okay as long as you saw it coming.
  • With all this changeup going to bigger wheels, the frame would need to be taller and denser than I’m used to – I tend to lay a lot of components out flat since the bot bases were always very wide.  I’d need to pay attention to the center of gravity of the bot and make sure it can even still grab and lift things.

While these thought for Clocker were ruminating, I was also doing a bit of lookahead – we in fact bought a good handful of bouncy 8-12″ wheels for PRODUCT DEVELOPMENT REASONS (no, like actually for the products) which were a convenient time to sample tire candidates for Overhaul itself.

In summary, by Dragon Con’s end, I had the following anchors dropped for Overhaul 3:

  • It must reduce the drivetrain complexity and ideally run with 1 motor per side instead of 2, such as the C80/100 motors we extensively used before, or their equivalent today.
  • It needed to have the choice (at the time) of either a brushless powertrain or a brushed one. Tests during the fall, and with Sadbot, were to help with this design fork in terms of priority.
  • It will return to 4 wheel drive instead of 6 (with two awkward small front wheels). The wheelbase should be made as long as possible to accommodate for center of gravity needs, but….
  • It will be a lot taller and more squat looking, more Overhaul 1 in appearance, to accommodate large compliant tires
  • It needs to have tractive ability from as many angles as possible – dead upside-down, angled up-side down, butt-traction, etc.

Well, that seems like an all-new bot to me, doesn’t it? I’d said before that I’ll run Overhaul 2.x into the ground first before building a new one. But I think to be realistic, I have no other choice – modifying everything to try and satisfy these needs didn’t seem remotely practical.  Ideally, I figured, I can keep costs down by greatly simplifying the chassis design, to move to a “somewhat modified barstock” method like Season  3 Brutus or a aluminum tube-and-shapes construction like Stinger or Whiplash.

Let the Design Games Begin!

 

The “insect” classes – 1lb and 3lb bots, have foamy model airplane wheels, generically called “Lite Flites”, for the bouncy one-piece wheel solution.  Heavy bots have solid/flat-free utility wheels, which in fact a few builders cheekily call “heavyweight Lite Flites”.

In the middle, though, I haven’t really seen any compliant wheel solutions, at least not uniform material ones. What I do know exist are “shooter wheels” for robot competitions like FRC and Vex.

So I went back to good ol’ Andymark and VEXPro and checked in on what their latest lineup for these products are, and what do you know – the mass commercialization of robot competitions (BACK IN MY DAY… -me) has really diversified the product lines. Now these squishy flexure tweel things are available in multiple durometers and materials and hub configurations!

I figured my solution would be somewhere in this realm, so I got a small sampling.

I rather liked the Vex straight-flex wheels. The Andymark design is overmolded rubber on a solid core, which I felt like was more of a potential failure point, so I went for these Vex Versahub compatible 4″ diameter ones. I got a few VersaHub components along with them to see how I could make integrated drive hub solutions.

In handling these wheels, I found out that they’re maybe just a little too compliant to run as single wheels, even in the 40A hardness. What happens is, they deform between the spokes fairly badly and begin rolling more like octagons. So at this point was when I had the idea of doubling them up – they’d better approximate the aspect ratio of a fat utility wheel or small go-kart wheel anyway, and would contribute even more to available contact area. #BotsGotDuallies is an idea that might also make it over to Overhaul itself.

One of my perennial FAQs when I taught mechanical design lectures/seminars was “Where do I even start?”. Good question – what’s the first CAD file made of an Airbus A380 anyway?

I usually told people my preference is just to make one of the small, well-defined subassemblies or parts first. You can always come back to any aspect of the design later, but “grounding” the design will help lock in variables and drive other placement and geometry needs. For me, it’s almost always the drivetrain of the bot and furthermore, almost always a wheel.

So there it is – I spent a few minutes staring at the Vex parts while thinking of easy ways to put them together. I ended up settling on using the Versahub sprocket on the “wrong side” of the hub itself so I can have a wheel on one side and a sprocket on the other. I think you’re supposed to use the Vex provided spacers with the sprocket on the projecting boss side.

This assembly is the kernel of the new 30haul drivetrain. The front hubs will be keyed to mate to a live driveshaft instead of being an idler, but the rear hubs will be bored out for bearing inserts for that role. Why this configuration instead of the multiple wheeled, indirect chain drive of Clockers past (or of Overhaul present)?  That’s influenced by another durability and “mobility in depth, at all costs” consideration to be explained.

I then started with dumping geometry haphazardly to think of some high level part placement needs. See the yellow square in the middle? That was an initial placement candidate for the main lift motor. It was a study in whether or not I could separate Overhaul fully into an upper and lower half. Right now, it’s basically there with the interface between the main lift gear and its pinion being where the bot can be “split” vertically when the arm towers are unbolted. Because I was anticipating the whole chassis becoming denser, I figured the lift motors might eventually make it upwards, especially with bigger drivetrain components possibly having to occupy where they roughly sit now.

As a sketching guide, I overlaid and mated the sketch into a dummy assembly and started organizing existing 30Haul parts into it.

One of the major improvements I wanted to make, as I mentioned, was greatly simplifying the frame design into something easier to construct on the inside, but keeping the bot’s visual identity on the outside. Unlike Overhaul 2.x or even the previous 30haul/Uberclocker which sought to imitate its topology, the frame of this new design is 5 major rails and a few plates/covers, ideally down from 14 parts.  All of these rails will simply be end-drilled and tapped – no fancy corner mating blocks (I’d favored the mating block/nutstrip approach back in the day when my fabrication means were much more limited).

Will the wheels be exposed? Absolutely. Is this a bad idea? Maybe a little. Here is where my “mobility in depth” plan is fully integrated.

I realized that the doubled up wheels could offer a defensive advantage. If they are mutually connected by “not much”, such as purposefully weak bolted connection or some shear pins and the like, then under normal driving they’d act as one wheel but the outer one will be very prone to shearing off once a big enough hit gets registered. For these Vex wheels, you’re supposed to bolt through them with spacers. I’m electing to use nylon standoffs to be threaded into from both ends – so the only connection between the inner and outer wheel is nylon. I got this idea from the HDPE side bumpers I installed on Overhaul in anticipation of the War Hawk and Witch Doctor matches – they’re designed to give me an extra life if it got broadsided, tearing off first and hopefully allowing a clean escape, which they did until I ran out of them of course.

The next element is why I have the front axle as a live, driven one. Overhaul 2.x has all “dead” axles – they add immense rigidity in the neighborhood of the axle connection. In Uberclockers of the past, I’ve then indirectly driven the wheel with another chain or serpentine chain setup (ooooh, instant single point of failure) or, as in the case of Überclocker Remix, through a gear. I’ve far more been a dead axle guy, is what I’m saying. The premise of this change is to have the dead, idler wheel in the back and the live driven wheel in the front. The rear wheel will be the most exposed and vulnerable, so it should not be the entry point of power into the system. The front wheel, in an ideal world, is going to be hiding behind the Overhaul-shaped wedge pods for one, and whatever else I put on the side of the bot.

I could make the front wheel technically also an idler and use an indirect chain or a gear drive. But the durability advantage I also want to confer is toleration of being bent. If the axle is bent and the wheel is wobbly, chances are another drive chain won’t stay on and a gear drive will no longer mesh correctly. But a live axle spinning in two self-aligning bearings may still stand a chance of both just transmitting wobbly wheel motion and hopefully, with the bearing constraints, prevent the bending motion from being propagated to the other side.

All of these combined inform the drive system placements for 30Haul. I decided to mount the wheels directly to the BaneBots P61 gearboxes here, for simplicity. For Overhaul, it’s likely going to be a double bearing system with an internal intermediate sprocket/gear stage if I can’t get a good direct motor placement.  I’d prefer to keep the motors as close to the rear of the bot as possible still anyway, for center of gravity and balance concerns.

In the most ideal worst case scenario (?????!) possible 30haul/Overhaul can take a direct broadside of some kind, get a wheel(s) pinched off and get flipped over, and I can skitter away with the remaining wheel on the other side (or be completely operable still with the “inner duallie” on the damaged side), self-right, and try to return the favor. That’s my story and I’m sticking to it.

 

First passes at generating frame rails are more or less complete – there would only be slight dimensional shifts from here.

Another major facet of Overhaul 1.0 inspiration that’s making it back into the design is the “wall of wubbies”. Overhaul 2.x was designed more like Überclocker since I obviously had that creative leverage, with the frame and drivetrain extending under the lift point where an opponent would be. Optimal, perhaps, for carrying, but it complicated the chassis and those front wheels were always a source of maintenance concern (since putting so much force through even smaller than usual wheels made them come apart or wear extremely fast).

If you recall from looking at Overhaul 1 in its early stages, it just has a big rail of rubber shock mounts on the front. This was definitely a compromise with the frame we already had put together, and they proved to be too bendy in operation once we really picked something up, like Bite Force.

Wubbies need to be spaced apart to approximate being used in tension and compression to be effective – they’re not very strong in either shear, or direct application of bending.  The idea was to give 30haul a “wall of wubs” of its own, but angled, numerous and in mutual contact, and with the outer ones arranged to mimic the ‘pontoons’ of Overhaul 1.

 

I’m testing the arrangement of the above-board lift motor placement here. While I like it, it had an unfortunate side effect of placing the motor directly in the path of the clamp arm. I’d have to sink the motor below the top plate level (making mounting more complicated again) to prevent this, or make some kind of U-turn drive to keep the motor package contact.

This is a manifestation of the robot part quantum principle that I’ve talked about some times. It’s harder to arrange parts in a smaller bot, because they are relatively so much bigger. A motor package not all that much bigger than this 42mm brushless setup plus a gearbox – my 63mm brushless motors into BB220 gearboxes – is used in a robot almost 10 times the mass and over twice as large in every dimension. Just the flexibility of having more volume to put things could be enough to mitigate design conflicts.

So I wasn’t really feeling this placement after a while. I’ll keep it in the back of my mind for Overhaul itself, though.

Therefore, the next stage of the design after a lot of rough geometries and placements were done is to push things around and see if I could get a more satisfactory solution. I moved the lift motor to a position rather close to under the lift gear. This allowed all 3 of the major motors to be in close proximity, which was nice, and it changed the forward bulkhead seen in the previous photo to a horizontal one that supports all the motors from below at once.

The downside? I had to shift the front wheels back to accommodate this position change, unless I wanted to implement the indirect-drive internal chain setup right away. Given that I was more interested in the bot as an exterior topology test, I didn’t want to add complications at this stage.

So I already knew 30Haul is going to have some center of gravity issues. I was fine with accepting this as an experiment to get a feel for how Overhaul 3 might drive (and Overhaul 1 DID drive – the placement of things is not all that different between it and this design!). It was clear the design would come in underweight anyhow, so worst case I’ll add a Shiny Metal Ass as a counterweight.

The next episode: Filling in more of the CAD details and executing my famous “Build it as I design it” strategy. I think the DoD calls it “Concurrency”. Say, how’s that aircraft carrier coming along?

Operation RESTORING BROWN Part 7: The Epilogue; or, Dragon Con 2019

Nov 25, 2019 in Dragon Con, vantruck

And here it is, the final chapter of a summer that was so full of content that it felt like an entire year; a summer that saw me dive deeper into silly van restoration than ever before, within a year that saw the company double in size, move to a new facility, and shift product lines. That’s a lot of things going on in just the past few months, and I often say that very few people can both profess to having such a life content density and tolerating it – but that’s for another Philosoraptor Charles Says post. This post will cover the continued little details from before and immediately after the Dragon Con 2019 trip, but mostly focus on the trip itself in a Vantruck-relevant way.

In the mean time, here is the full Book of Van:

  1. Episode 1 – the initial teardown of the house of horrors
  2. Episode 2 – Welding and repairing the major roof seam holes
  3. Episode 3 – Wrapping up electrical loose ends, some times literally
  4. Episode 4 – Actually painting the cab… using a Harbor Freight paint cannon
  5. Episode 5 – Putting the van and truck halves back together
  6. Episode 6 – The finishing touches on the exterior, and working on the interior

So to start, I basically skipped all of my usual robot building that goes on in the summer months. There WAS a dumpsterbot, of course. That was put together literally the week beforehand, since I did end up getting itchy robot fingers, and had a convenient gift available to perform unethical experiments on. In a way, Vantruck was to be my Dragon Con 2019 entry, along with an extended (for me!) trip away from company affairs. Of all possible vehicles you can go vacation with…

 

One of the last changes I made was getting a stock, OEM tailgate. You may remember Vantruck having a white dented tailgate, then a black airflow/5th wheel style one. My van salon determined the white dented tailgate was probably not worth trying to repair and then paint, as it was bent enough to not close properly, whereas I could score a gently used one on Craigslist for around $100. And that’s what I did! One weekend prior, I journeyed down to the Cape (yet again) and got this very nice condition tailgate. It’s actually dark green, not black, but is so dark green that it’s only visible under bright sunlight. The plan was to have the bed and tailgate repainted together once I returned; my intention is to ditch the chrome panel (more space for anime stickers) afterwards.

And so it was that I set off bright and early when i woke up, so like noon on August 26th. I took my usual “New York Avoiding” corridor and encamped in Harrisonburg, VA at my favorite Motel 6 on Highway 33 – why the entire fuck do I have a favorite Motel 6 now – and continued onwards to North Carolina thereafter.

The goal was to hit up US 129 and other idyllic mountain roads in the Smokies, then descend towards Atlanta after crossing into Tennessee.

Somewhere on I-77 in Virginia as I began the descent down the Blue Ridge…

I encamped again just west of Asheville, NC and was well-poised the next day to begin #VansOnTheDragon.

 

But first, a van friend somewhere in Asheville’s further reaches!

I continued all the way into deep western NC on U.S. 74, then NC Highway 28, switching onto NC 143 to get to the Robbinsville area. The roads got incrementally narrower with each intersection!

Vans and the Dragon sculpture?!

Some say the place is oversold and overdone, but I personally would like to see more of this kind of thing across the country. Obviously there’s very few roads that would beget being this kind of attraction, since it would need to be sparsely traversed by locals and not have intensive development.

So how did it go? I ended up doing an outbound run and then back inbound. It was an entire different world from when I took Mikuvan in 2016 and then again over this past winter, which itself is an entire world away from doing it in a real sports car. Mikuvan is at least somewhat capable of performing agility-like behavior, what with its low mid-mounted engine, rear wheel drive, rack-and-pinion steering with independent front double wishbones, and 52/48 weight distribution (Look all of this up. I have an exotic 80s sports car and none of you get to contest this). I can predictably squeal all 4 wheels on the many turns, and I never felt like I was about to sail off a cliff.

This time, I was basically driving a moving truck. Let’s face it, as tarted up as Vantruck is, it’s fundamentally still a U-Haul. It’s exactly the width of the road more or less, and there’s no steering feedback. Every move needs several turns of the wheel to accomplish, and there were a lot of god damned turns. I called this the “yeet the steering wheel” effect since I basically was standing up in the seat throwing the steering wheel around.

It also has an unfortunate positive-feedback state that occurs in turns if the outside wheel hits a bump. There’s some element of the Ford double-crossed-T-rex-arms (not actual name) suspension that interacts with the tires and possibly some very stale shock absorbers where the outside wheel will begin bouncing up and down, taking a good second or so to oscillate out. Obviously this causes traction loss and instantaneous understeer until it corrects itself. Color me enthused when I discovered several of the banked outside turns could excite this “mode”. Luckily, I have experience with this on curly highway offramps; just tapping the brakes will typically end it. But those cliffs got mighty inviting looking!

If you’re interested in seeing a very slow and soothing (from the video) drive through the Dragon, you can check out my dashcam upload of the outbound and the inbound. It’s not very exciting to experience just as a video, I can say that much.

A few local photographers are usually set up on the most scenic hairpins, and so I now have a couple of nicely done “press shots”. Of these, I tend to patronize Killboy.com the most – consistently they seem to have the best composition. A couple I bought from another vendor had visible roadside grass in the foreground, for instance, and others were under-exposed (possibly too fast of a shutter to try and minimize motion blur) or I flat out didn’t like the angle. Here’s one of the wide ones – check out the suspension travel difference between the inside and outside.

In the middle of a #YeetTheSteeringWheel operation here. Observe the angle of inclination formed by the Miku keychain plushie in the center.

And lastly, one of the other good ones – I call this “Ford stance” because every Ford vehicle lineup photo.

(I owe the whole world an explanation of what Waifuworkz is – one of many explanations of many things this year I owe in due time)

 

Well, we’ve made it to the end…

I decided to only get a small sticker, since there was no need to announce to the world that you can be qualified to drive a school bus for rural Tennessee-North Carolina school districts.

From there, I headed southwestwards on US 74  all the way towards Chattanooga, TN. US 74 is a wide state highway until it begins following the Ocoee River, upon which it becomes another 2-lane road with uncomfortably close rock faces. This part is extremely scenic, more beautiful than technical, following the whitewater river for several miles.

The nice thing about taking state roads? You get to stare at everyone’s hoarded decrepit property in their front yards, a likely prospect for me in the future from the other side. Like, look at this gorgeous mobile shed:

That’s a “The Diplomat II” Class A motorhome. It seems like it would clean up quite well, honestly. I didn’t check if they were selling, however.

I rolled into town on Wednesday evening, and proceeded to spend that and Thursday taking some random landmark photos. For instance, the “Duluth Jesus Sign”:

This sign just says JESUS on both sides. There’s not a church or pastor or other evangelist figure advertised on it. It literally just says JESUS, abutting I-85 next to a few hotels.

 

Checking out the Big Chicken in Marietta!

 

…and causing traffic problems at the AirBnB house  I got for the convention with my vanspread.

 

Whoever you are, you have an excellent taste in off-road vehicles.

Here we are at the convention! The central lot between the Marriott and Sheration actually has “RV and bus parking” for the weekend, a rare find nearby. That also includes silly van parking. Quite a lot of folks seem to take advantage of this alternative to having to get one of the expensive hotel rooms. Behind the Class A on the left were several more RVs and trailers.

Vantruck isnt’ a good option for camping an entire weekend without having friends that have other facilities such as bathrooms and kitchens. However, I can see how a truck bed camper could alleviate this if I were so inclined.

Found in the same parking lot a few rows away, though, was a van friend!

I couldn’t get in close enough for a photo since the lot was pretty full. This was a pretty cool custom “turtle top” style high roof E350 build with an observation deck up top.

It looks like this was made out of a gently modified school minibus. Overall, very tall and quite impressive. The utility bumper on it appears to be custom made, and a larger version is what I have on deck for my personal design.

For my local get-around needs without having to vanspread everywhere, I made extensive use of rent-a-scooters. I did this some last year, but the rent-a-scooter ecosystem is now fully entrenched and some argue it needs population control, deer hunting style. To be entirely fair, I do agree after seeing just how many get thrown around on the street and not arranged in any useful way. As for exactly how, well, that isn’t my business problem.

My favorite new contender? These things. Not even scooters, but silly shaped e-bikes. They had wheels (hhhue) that were big enough to actually traverse both road features and sidewalk seams/cracks, and most importantly the curb cuts between them. I’ve generally been lukewarm on the actually scooter-based transit options since I didn’t think making the handlebar higher (to prevent you from being catapulted) was better than upping the wheel size to prevent it in the first place.  They also packed more power, and with the better riding position, meant you can actually use it; there’s no point in putting 500+W into a compact scooter shape.  Trust me on this one, I’m an expert!

Sadly, they weren’t as prevalent and widespread as the flood of Bird and Lime scooters. By the middle of the weekend, I actually went to hunt these down and bring them nearby wherever I was, because I liked them immensely. On Saturday, the most crowded day, I left Vantruck at the AirBnB house instead of fighting for 2+ parking spots at the same time – and hit town with one of these things.

 

 

I have a suspicion that everyone thinks I look just like this guy when I cruise around with Vantruck.

Anyways, one final Van Friend on the way back up:

 

This guy was doing whole #vanlyfe thing and the van was kitted out with a generator and lots of, uhh, rooftop storage.

I ended up staying the rest of the week to do some more Atlanta Things, setting back north that weekend, and getting back into town Monday morning. I’m very proud to say that Vantruck did not make a peep the entire ~2700 mile trip. I suppose the “van tax” that’s normally reserved for the Autozone parking lot or a U-haul trailer was just directly subsidizing the Houston, TX economy instead: The end-to-end gas mileage for the return trip was an incredible 10.1 mpg. Hey, double digits!

(I didn’t do a calculation for the trip down since it was indirect and involved a lot of fumbling around mountain roads).

Would I do this again? Probably, but only once a year. I have better ways of lighting money on fire for fun, such as robots.

While the “couching down the highway” effect is very relaxing, I’m really too small for the driving position it was designed for and it gets unergonomic after hour #6 or so. The seat is literally too deep for me to fill up, so I either have to slouch a lot (then I don’t see over the dashboard!) or kind of sit more on the edge, which isn’t conducive to back comfort. This is on my list of issues to address, namely getting rid of the couch-like front seats and replacing them with something a bit more modern.

The last remaining kibbles

The only thing I left unfinished due to time constraints before Dragon Con and not desiring to commit the money yet was painting the bed. I had it sanded by friends the day we commenced on cab painting, but didn’t follow through, so the bed was a slightly different texture and color than the cab for the trip.  You can’t really tell in the photos though, much like the tailgate looks black enough.

After I got back, I decided to just have Maaco blast the thing. I had, at that point, talked to enough friends and people who had worked with them that my pre-conceptions about the company, springing mostly from Reddit horror stories, was more dialed back. I figured, too, the bed was a limited scope thing that (much like I did) was easy to handle independently, so I wouldn’t even be too mad if they did a me-quality paint job. Remember, I only go to mechanics and hire services when I’ve dug myself too deep. Yes, I’m one of those people – but I also like to think I know when to throw in the towel before things get horrifically tragic.

 

So I did a little of #BigChucksAutoBody and smoothed over some of the cracked areas and larger dimples that were primarily in the fiberglass fenders. No use painting over cracks and dents! Then I submitted it for consideration to a local Maaco branch.

A few days later… well, they definitely did the thing. Far better quality than I could have ever pulled off. They of course took the opportunity to let me know I can stop back any time to have them redo the cab properly!

 

The hot tub then goes back in, and the toolbox on top of that — I didn’t take a picture of it since plenty of photos exist with the toolbox.

With this, I’m declaring the end of Operation RESTORING BROWN! There’s no near-term changes I am aiming to make at this point except more anime stickers.  I’ll sum it up this way: It costs way less than robots would. As I mentioned last post, the end to end restoration cost was around $2000, and with the bed paint job and some small incidentals, we’re up to more $3000, which is still like 1/3rd of an Overhaul. Even counting the entire expenditure of Dragon Con including the far-exceeding-plane-ticket fuel bill!

But personally, I still found it not as enjoyable as robotting for a summer, at least with the fleeting facilities I have. I don’t have the capability right now of putting down infrastructure, so it’s working with what time and space I can get. It’s a lot messier and grungier, whereas at least a robot mess is usually just metal chips, not being covered in mysterious substances of varying carcinogenic rating.

The upside? It’s still a utility and a tool I can keep using, but now it’s nicer. I’d say it’s more akin to restoration work on a machine tool in that regard, such as the work I’ve done bringing Bridget and Taki-chan back up. I’m sure my assessment would be a lot different with a fixed workspace that I can embed into as hard as I’ve done with MIT/company facilities and with building robots. Vans are just simultaneously portable and very not-portable.

There are, of course, things I definitely want to do in the future. For instance, I still have the designs for the rear custom tow bumper and cow-destroying chin of power, but I’m going to shelve them and return to robotting – after all, the fall is really just preparation for #Season5. I’d like to focus on the interior next year, possible finally getting those new seats and having the floor re-upholstered in something that’s not (in the words of an auto upholsterer I visited) actually house carpeting. STAINED HOUSE CARPETING.

But in the mean time, I have plenty of market-fresh robot content to come!

Operation RESTORING BROWN Episode VI: Return of the Van Lights; the Conclusion

Sep 21, 2019 in vantruck

Yes, I avoided mucking up a Star Wars title in the way everyone wants me to. SHUT UP. Nobody asked for your opinion. Well, you probably have figured out what’s gonna be presented, so why not just read the other 5 parts first?

  1. Episode 1 – the initial teardown of the house of horrors
  2. Episode 2 – Welding and repairing the major roof seam holes
  3. Episode 3 – Wrapping up electrical loose ends, some times literally
  4. Episode 4 – Actually painting the cab… using a Harbor Freight paint cannon
  5. Episode 5 – Putting the van and truck halves back together

 

So we begin this story the week after the Regular Car Reviews show, which was an absolutely fantastic time. I only really had a few things I wanted to take care of before Dragon Con. They were, in order of importance:

  • Re-mounting the rear sofa bed/bench seat
  • Bringing back the Next Generation Sex Lights as I mentioned before, and
  • Adding lighting to the running boards

Let’s begin! Chronologically speaking, the running board lights were first and the NGSL were last (days before I left), so we’ll go in that order. To be truthful, the story of the running board lights extends all the way back into late last year when I started doing some lighting investigations for custom bumper designs.

Fun truck-related trivia: Gratuitous amber marker lights are some times called “chicken lights” in trucker-speak. The origins of this are not too clear, but I mentally file it under the same generational oral tradition that gave us things like “Pitman arm” and “Schottky diode” – because someone called it that and it got popular.

The unit lighting products I decided to use, instead of drilling and mounting one billion tiny little lights, was called an “identification bar” – named for the mandatory “I am a big-ass truck of some sort” lights that are mounted to the rooflines of commercial trucks. The center three lights are often supplied as one unit for quick installation. I was going to just use a couple of them linked together.

Par with my usual shopping technique, I cross-compared eBay, Amazon, and a bunch of independent vendors to see who was offering the same Chinesium for lowest cost-to-me. Since the products are nominally fungible (e.g. at this point in history, there’s not gonna be that much difference between two LEDs of different pirate manufactueres), this is a good tactic, and I was able to get each bar for just over $12 each, so about $150 for both sides, on Ebay.

I spaced them out to look visually correct, then back-CADded them to get a regular pattern that I can start drilling into the boards.

(Excuse the camera-screenshot – I took this literally to message someone on my phone, in the truest possible Millennial way, then decided to keep it!)

Fast forward to the #VapeShop, and I’m marking out everything and drilling the holes after “work” one day, in accordance with my drawing. Wait… what am I doing at the company shop again, when I have Big Chuck’s Auto Body?

Sadly, I lost Big Chucks’ Auto Body at the end of July, when my lease expired. The first week after I got back from the RCR show was filled with moving my stuff out, into the “Cruft corner” of the #VapeShop.

I anticipated this happening one day soon, since it was unlikely that the property company would keep renewing a lease for a rando when they have legitimate businesses they could rent to instead, so all of my goods that were heavy or unwieldy were on wheels. It took one truckload to get my shelves and toolboxes and stuff out – the workbench you see was left behind, since we got better ones! Yay!

May my mis-sprayed paint forever stain the ground!

 

The power hookup for each light was pretty simple, as they were frame-grounded, so I had to just wire all the modules together. I’m not too much a fan of frame-grounding, so I ended up making a separate “ground wire” that was really just bolted to one of the mounting holes as a ring terminal, terminating in a 2-pin connector (which naturally I scavenged from a product part bin).

And then onwards we go! An hour of surgery one night to add the corresponding 2-pin connector to the existing lines I ran downwards from the front marker lights to the area right behind the front wheelwells, and the fried chicken lights as I termed them were all set to go.

Next up was putting the rear seat back on. I had this idea in my head for a while, once again, so it was merely execution. I wanted the rear seat to potentially be modular and removable for any other attachment I had in mind in the future. The factory method was just driving some bolts through the floor and using what basically were just pipe clamps to hold the whole damn thing down. In fact, it jiggled natively.

My solution was one that I actually saw at the Van Nationals show in some camper/vanlife style builds, and only heard of in passing before: L-track. Also called “airline track”, it’s an aluminum rail profile with standardized hole patterns and anchors that you can use to attach “stuff” with. The idea is that an anchor fits into the round cavities and is locked in place by a retaining bolt, typically taking the shape of another anchor.

So I ordered some off Amazon.  In measuring out the remnants of the seat mount, a 24″ section was actually a perfect fit, and you could get it in 24″ lengths with a sack of questionable anchors! LUXURY!

To mount the L-track, I wasn’t just going to zip it into the floor, but build a frame to adapt the haphazard holes drilled by Centurion to something vaguely standard. They didn’t seem to pay much attention to WHERE the holes were drilled – some lay on the slopes of the floor stiffening stampings, others on the bottom of the valleys of the same. The front set of holes was more 41.75″ apart than 42″ (a standard width in the van world, as I found out, for seat mounts) and the offset from the rear cab wall also varied.

In other words, this rigid frame had to compensate for all of the absolute bullshitt they got up to and turn it into something vaguely square and regular. I made it with some spare 1x1x0.075 wall steel tubing at the shop, and pretty much freeballed all of the measurements after making confirmations.

The result was then MIG welded together.

Test fit of the frame to double check all of the planned offsets, shifts, and transforms lined up!

Indeed they did, so I naturally painted everything my favorite color before mounting it all up. The steel frame is bolted through the floor using a number of steel and rubber washers as spacers – steel for height offset, and rubber for conformation to the varying hole placement angles. The L-track is then screwed in from the top into the steel tubing using each rail’s five 1/4-20 countersunk clearance holes.

 

Next up was the seat mount itself. What you see are split clamp shaft collars with the bottom halves drilled radially downward, for the threaded anchors of each L-track stud. These bottom halves are permanently threadlocked together with the L-track studs. I used a 1″ diameter piece of tubing (the same diameter as the seat rails) as a template to get them to the right alignment. When these are mounted, the shaft collar clamp screws and upper halves will then be tightened in permanently with the same threadlocker. They don’t come off ever again – to remove the seat, I would then release the four hex nuts that hold the anchors to the L-track.

This is the assembly fully mounted and tightened. Again, the shaft collars are considered part of the seat now. If I wanted to shift the seat forward or backwards, I’d release the L-track hex nuts and do so; same for complete removal.

(At least until I buy the new van sofa bed with the same mounting dimensions, that is!)

Everything still folds down! A side effect of my mounting setup, though, is that the seat is now a good 2.5″ higher than it was before. Not the end of the world, I suppose.  The companies making van sofa beds still are all made-to-order outfits, so I might be able to convince them to shorten the height of any future one I get. It does get awkward to sit in if you’re short, however, since you no longer reach the ground…. like me.

Either way, I consider this far more improved than what were basically fucking P-clamps for pipes.

Now we move onto the final and most glorious step, the one which I went extra out-of-the-way weeks before to ensure can happen: the Next Generation Sex Lights.

From Episode III, the touch-me LED controller makes a return! I decided to go ahead with its installation since to do any light install in the cabin would have required basically the same amount of work.

I measured up the rectangular body of it and cut an accordingly rectangular hole into the center console.

This was when, on closer inspection, I (re?)discovered the mounting holes were exactly aligned with an edge of the rectangular body.

What in the actual fuck is your product design division doing, mysterious Chinese company who made this?? Nobody at all thought about how this would be installed, huh? First we had the teeny tiny ribbon cable connecting two snap-fit parts requiring a lot of force to actually un-snap…. and now the mounting hole which, if you cut the indicated panel size out, would actually sit right on the edge of said cutout and not off to the side.

I don’t get it. There’s NO way anybody has installed this product the way the originators wanted.

And I’m not going to either! The touch-sensitive bits, after inspecting with a strong flashlight shining through the whole assembly, are really just restrained to the touch-button area. I was afraid of bringing too much metal close to the buttons just in case.

So you know what? Forget your actually-mounting holes. I’m just going to drive four screws through the corners and move on with my life.

If you choose to do this (for some reason…if you buy one), I used the ‘triple point’ where the edge chamfers meet the main flat face.

Here’s the backside of that installation – locknuts that are gently torqued will hopefully not crush the whole thing!

The lights themselves are the RGB+W strips I bought mounted in “corner” LED housing. You can buy this extrusion by the foot/meter and it comes in several shapes to accommodate different LED strip widths. I merely cut them to length, shoved the strips in, and soldered a small length of the 5-pin RGBW cable to each end, sealing the ends in hot glue. The plastic cover is a bit tacky to snap on, but with some extra coercion it stays on fine.

And here we have it. Six mounting brackets screw into the interior walls, and the LED rails snap right in. I made a splitter that interfaced with the original cable drop to fan it out to both of the LED rails. I really like these more lower-profile light bars compared to the “behind the curtains” style that came with it. It’s a sleeker, more modern look to contrast the antiquated American luxury this thing represents. The camera exposure makes them look more obnoxious than they really are, by the way. Along with the adjustability of the LED controller, they are actually quite tame to be in a direct line of sight scenario.

Meanwhile, on a fortuitous trip to New Hampshire, I had scored this gull-wing toolbox off Facebook Marketplace. I’d been actually looking for a gull-wing box in particular, because I preferred the accessibility from the sides. They tended to be more expensive than the usual one-lid, rear access ones, so I never went to the effort of buying one. Instead, I guess it took being in the right place (Manchester, NH area) at the right time to see a relatively fresh post, and divert course while calling the seller and confirming location and price.

These toolboxes typically call for drilling the truck bed and bolting them in to the side rails via the skinny parts at the sides, but it seems like this one was set up for a “no drill” style clamp mount that latched to the underside of said bed rails.

Absent buying the matching kit, I just stopped by a Tractor Supply (my favorite chain store now after Harbor Freight) and bought these J-hook bolts.  To avoid munging up and denting the bed, I added the fine touch of a strip of heat-shrink tubing and a vacuum line plug to each one before throwing them in.

And so now, without further ado, to conclude this #VantruckSummer….

That’s all! It was a crazy adventure that I really couldn’t have hoped for going any better. Any one of many possible delays could have pushed me into having to reassemble everything as-is and call it quits, or at least forced me to delay everything beyond having the mental tolerance for.

What’s next for vantruck? From a physical appearance perspective, nothing really urgent. I’ll get the bed finish-painted soon, and beyond that, who knows!? My short list include a small amount of bringup on the interior, such as repairing/replacing the crystalline 1980s acrylic cupholder. New seating is on the docket, but it’s expensive and non-urgent (It would cost around $1900 to get two brand new captain’s chairs and a sofa bed). The near-term expenses would probably be a few hundred to get the bed finished.

In total, the restoration to this point has cost me about $1500 out of pocket not counting capital equipment and tools such as #Limewelder, the paint cannon, and some sanding tools – if you count all that it’s more $2000. Still, this is far less than what any “professional” restoration would have cost, especially one which would perform similar levels of craftsmanship for future-proofing (I do emphasize a LOT on future-proofing versus just making it look nice, to be fair!).  I’m not gonna count “labor equivalent” time at all since this is still just a personal project of mine and I can’t expect someone else to do it to the same creative mandates.  The biggest single line item was the paint – which was about 2 gallons total for about $400, and otherwise a lot of small things that add up such as hardware, new-old lighting products, wiring and connectors, and so on.

I’ll probably leave this thing alone for a while to focus on getting back into gear for BattleBots next year ….. there IS a season 5, right guys? Right!?

But the most important part is what y’all were waiting for:

Vantrucks on the Dragon.

 

Late Stage #PostmodernRobotics: Welcome to Your Waifu is Trash, the Robot Dumpster Fire

Sep 14, 2019 in your waifu is trash

Now that there is an #BrandNewSentence.

Ladies and gentlehams, this is a Golden Dumpster.

It’s several things. First, it’s the prize if you win the Norwalk Havoc event held roughly monthly at the 50Day Makerspace in Norwalk, CT.

Second, it’s a repainted Dumpsty desktop dumpster. No, this is not a joke; someone’s real life job in a shop and assembly room somewhere is manufacturing tiny dumpsters for consumption by edgy postmodernists everywhere.

Third, it’s about to be digitized and turned into a robot for Dragon Con.

Yes, this is truly the state of combat robotics today. This is what we’ve become, when all of the Ampflow brushes have melted away and all of the poorly-restrained Li-poly batteries have vaporized, the essential oil of the Harbor Freight drill gearbox. Welcome to #PostmodernRobotics.

So alright, what’s the actual story here? This is starting to feel a little bit like Stance Stance Revolution or Colsonbot.

In a way, it kind of is in the vein of those two. They’re all supposed to take the super cereal sport and turn some element of it upside down for entertainment. As you know, I tend to complain about how overly tryhard the sport has become especially with folks getting into the sport only building spinners (or worse…. only operating the same spinner for the better part of a decade) and focusing on win counts at rigid tournaments. Not that I have a strong moral basis to stand on here, since I obviously had my own era of “tryharding”. But regardless, in the position I am, I might as well keep at injecting whimsy wherever I can!

This dumpster is actually Jamison’s – not mine. I only took Roll Cake to one Norwalk Havoc event for kicks (where it did disturbingly well in a rumble, more than I expected by far!). It was bequeathed to me while Sawblaze was in temporary storage at Big Chuck’s Auto Body – you can kind of see it peek out in the background of a few photos.

Basically, we both wanted to see an assbot made for Dragon Con. With the time horizon for rebuilding Überclocker/30-haul vanishing, I decided to punt on the project instead of rush it (see, I’ve learned SOMETHING about project and scope management) and focus on putting on a show for the convention.

Obviously it was going to be almost completely ineffective as an entry – that was kind of the point. It’s too small to put any really worthwhile drive power in, at least not without actual engineering effort, and the dumpster itself actually weighs close to 8 pounds – it’s not a plastic shell, it’s actually stamped and welded steel sheet (speaking of engineering effort for questionable ends…).

My “goals” (???) for this build condensed as I was buttoning up Vantruck lighting. It was going to have powered flipping lids actuated by servos, and an internal vape system to emit a lot of thick smoke. I was just going to drive it around the convention as a neutral political statement – you can project any insecurity you want upon it! It doesn’t mean anything and nothing matters! True #Postmodernism!

 

I made it a curiosity goal to see if I could get it to “self right” with a linkage that allowed the lid to extend far enough. Granted, it can only ever self-right from one face only, so how much would it really matter? Does anything actually matter?

After a couple of iterations, I found a good enough solution where a 120 degree servo travel was enough to get about 200 degrees of output travel. The linkage consisting of the servo crank arm, the lid, and the coupler link in between basically was almost toggling at both ends (very folded one way or another), but was much more squared up when the lid was vertical, or when it would have the apply the most force to “get up”.

I was going to need a hefty servo – probably a 1/4-scale size – to do this motion anyway, so I was browsing for candidates as this process was happening. The short turnaround time before I was leaving kind of mandated a Jeff Bezos Special, and I ended up just going with one of these generic “60 kg” servos. No, they don’t weigh 60 kilograms, but allegedly put out up to 60 kgf-cm of torque. Do they actually? Who knows?!

They come in 180 and 270 degree travel varieties for different applications, with the latter being more rare, so I constrained the design to use the 180 degree type only just in case I had to find a spare. Always be prepared to quickly service your miniature flaming dumpster?

I was going to keep the drivetrain simple, using some 25mm diameter Pololu gearmotors I’ve had since forever. The “25mm diameter gearmotor with a centered shaft” seems to be a very commoditized motor form factor, and many generics exist and are popular with beetleweight (3lb) builders. Pololu sells a “HP” line which uses a hotter-wound motor that pulls more power, whereas the common ones on eBay and Amazon are very tame.

The drive layout was going to be 4 individual modules, with 4WD. Instead of just slinging a robot frame under the dumpster (sorry, I can’t take myself seriously typing that), which would pretty much guarantee it tipping over all the time, I wanted to hide the drivetrain within the bottom by making flange-mounted modules that attach to cutouts.

The drive bits itself are just four machined aluminum hex hubs for 1.625″ Banebots wheels I had on hand – dating all the way back to #CandyPaintAndGoldTeeth (which is a bot that REALLY could use a reboot!), and the motors are clamped in place with a U-shaped block.

I made sure to add an external support bearing for the wheels, since these motors do not have all that much output shaft support; one of the ways they get broken easily in battle is just by applying too much force to a directly-coupled wheel. They really should get external support, even in beetleweights (some get away with it using very soft and foamy wheels like Lite Flites), and definitely in anything heavier.

Here’s what it’ll look like from the bottom. The wheels are basically pushed out as far as they can go into the corners for …. stability. Yeah, stability!

I made the rest of the linkages based off the skeleton sketch model. By this point, I actually got the “60kg” servo in house, so I measured up its stock arm and designed a linkage to be sunken into it (for maximum torque transfer if this thing really can push 60 kgf-cm, I didn’t want to just rely on 2 or 3 screws)

And here we have the more-or-less final design, minus a few electronics detailed which were mostly freelanced as the build progressed.  Let fabrication commence!

Making the cutouts in the bottom of the …. dumpster … was actually more strenuous than I thought. This thing is straight up made of 18 gauge steel all around. Thicker than most Mikuvan body panels, as terrifying as that sounds. I used a Dremel with an abrasive wheel to make the cuts, then used a 3D printed prototype of the motor module as a drilling template.

These components are 3D printed in Markforged Onyx, a part of this balanced breakfast. The wheel outer bearings are thin-section Inch bearings I got a long time ago for Roll Cake – they’re type R1212, 1/2″ bore 3/4″ OD and 5/32″ thick. I rather like them for doing little inch-centric quick projects, such as this one!

Four of the motor modules assembled together. This is a very formidable beetleweight drivetrain, all things considered.

I went just maybe a little nuts on engineering a flaming dumpster by making the servo linkages all use ball bearing pivots. Seriously?! Yes – when you build a complex bot like Roll Cake, you end up with a million little bearings you bought but don’t end up using, and can peruse through later.

These bearings are type SMF83 – 3mm bore, 6mm OD, and flanged. They’ll ride on 3mm shoulder screws (also left over from Roll Cake iterations). Ball bearing pivots reduce the friction of linkage joints by a good order of magnitude or more, and reduce slop since they don’t need to have inherently loose fits – for a linkage as edgily-designed on the verge of toggling as the lid, I figured it would be a nice touch.

There are a couple of little 3D printing tricks that I’d like to point out. They’re not too visible in these photos, so it’s easier to show a CAD screenshot:

Basically every part on this bot is printed at an angle with the part not oriented “flat” like what’s common. I started doing this years ago, probably by accident while trying to print an awkward part, and realized it confers a lot of advantages.

First, you can distribute a load on a 3D printed parts in all 3 planes by tilting the part – at least going from one plane of loading to two.

In a part that has multiple orthoginal axes of pin joints or screw holes, instead of extremely compromising on the strength of one axis by forcing it to be loaded “between Z layers” where deposition modeling is the weakest, you effectively slice the part to include them in a skewed fashion.

That way, for example, my pin joints and bolt holes are all grabbing material on the 45 degree plane, each capturing many layers of material – clever part design with this in mind can even result in fasteners that capture the entire width and length of parts. This approach also makes 3D printing embedded trusses and other lightweighting shapes more effective for the same reason: the geometry permits material stress transfer into more planes and axes at once.

Second, by tilting some features, you can avoid support lattices in hard to reach places or which would cause poor finishes in a precision-requiring area. A lot of the parts were printed without support, only a “brim” on the lower 3-5 layers to promote adhesion.

The downside is your printer has to be in good tune to do this, since it involves printing almost exclusively in 45-ish degree overhangs and support lattices generated may be much smaller. I trust the Markforged machines to do it – a tunable RepRap-family printer might need some intensive training beforehand.

The electrical deck was freehanded from a sheet of 1/8″ Garolite, and the battery cradles and clamp designed up and thrown on print also. I designed around a set of 4S, 1.8Ah packs I already had, but made sure the cradle was big enough to support the next size up like a 2.2Ah or even 3.0Ah for longer run time. Remember, I was out to drive this thing around for the better part of a day, so it’s carrying about 4x the amount I would ever expect a beetleweight drivetrain to use in one match already.

While this was all happening, I was also waiting on paint to dry. Because of course I will make it Miku-colored!

I ran into some serious issues with painting it, though – the Golden Dumpster is in fact made from painting gold over a regular green dumpster, which is green paint over the bare steel. So I was adding shitty spraypaint on shitty spraypaint on more shitty spraypaint. Some of it started crinking up and detaching in chunks, which was unfortunate. I decided to just forget about appearances – a weathered dumpster with chipping paint and dents just sells the story!

Anyways, here’s the motor pods and electroncis deck dropped in and screwed shut.

The electrical system was actually a little bit of a conundrum. The big servo preferred 2S lithium voltages (7-9v or so), the drive motors were 12V rated so it’s best to run them at that or higher (hence the 4S battery chosen – 14.8V nominal). Most vapes run at only 1S (3.7V) or in that neighborhood. The receiver could take up to 12V in, but the Pololu R/C relay should stay around 5V for best reliability.

I ended up digging out an old adjustable BEC (R/C power supply) from the pile of robot electronics, which could be tuned to 7.2V, an old 6-cell nickel battery voltage. This would feed the vape power (and a mini air pump that is needed to actually push the vapor out with force) and the receiver. I tested the Pololu relay and inspected its diagram to see if there was anything that bad about running it on 7.2V instead of 5 – nothing ostensibly besides possibly overpowering the relay coil itself. Overall, 7.2V was a reasonable compromise for everything on board.

The BEC unit and Pololu R/C relay get globbed onto the electrical deck, next to the most overkill possible controller for this application… a spare RageBridge. Talk about being under-employed!

The smoke effects actually got super interesting. What you see here is two CosCloud units provided to me by their creator Alina. They actually figured all of this conundrum out for me (and you too! and many others!). I was otherwise going to a literal vape shop to buy literal vaping gear to make my own.

I’ll be running two of these “smoke generators” in series to line up with 7.2V pretty well, and the air pump in parallel with that group. This whole assemblage drew around 3 amps at Full Vape, which was quite tolerable with the 10A-rated BEC.

The final packaging and zip-tying now commences.

And here’s what it looks like from the outside! The final weight – 11 pounds 8.8 ounces. Hey, there’s room for a… weapon?

The dwarf dumpster fire, in its natural habitat.

And what it looks like in action at the convention. The secret is to turn on the Vape Turbopumps for a few seconds, then open the lid and watch it all waft out. This thing was an absolute riot everywhere it went, and it fulfilled the “neutral projection target” social experiment perfectly. I heard quite the range of things referred to while pointing fingers at it, from the usual remarks about Congress and the presidency, to the Marvel Cinematic Universe, Disney, Game of Thrones, Star Wars continuations, game companies…. there are apparently many ongoing uncontained dumpster fires in society as we know it.

Some of them even move around and come to you.

You can see #YourWaifuIsTrash in action in this Dragon Con music video (skip to 8:15 if the time link doesn’t work!)

And finally, we make it to the Big Day at Robot Battles!

I’m a dope for not getting to it sooner – somebody had to point out to me that the dumpster was missing an UWU face (yes, it’s a face, not a sound…. today you learned?!), and so one was hastily appended with markers.

This thing managed to actually pull off a win. I did it by basically bull-baiting the opponent at the edge of the stage and letting nature take its course.

Of course, it couldn’t push anything, could barely get over the “arena” borders which are left beat-up on purpose, and had issues with turning in place under its own weight and the traction of the outdoor style carpet of the stage. So that was all! I also entered it in both rumbles at the end, but it got bowled over rather quickly in both rounds.  Nevertheless, I consider #YourWaifuIsTrash a win, because what is a win in #PostmodernRobotics? It’s whatever you want it to be!

This thing came back from Dragon Con working just fine, so it will live on as a stupid prop for all of eternity. I’ll probably repaint (read: just spray over it AGAIN in more shitty spraypaint!) it soon and begin adding choice tasteful decals.

Do you want your own? The CAD files in STEP, IGES, and Parasolid are available on the References page!