My Life is Ruined Again: BattleBots Season 3 and the Triumphant Return (?) of Overhaul

chorl2 Comments 
> mfw season 3 announcement

The rumors began shortly after July, when Science Channel announced it was going to pick up BattleBots after ABC unceremoniously shat us out in favor of a …. boy band show? Well fuck me sideways with a fracking well, look at how that turned out for you guys! The rumors intensified in November as discussions and negotiations were clearly under way, and reached a crescendo in January, each week leaving us wondering if “next week” was going to be it.

Well, now they announced it. Crap. Now I actually have to finish something!

Overhaul’s upgrades have been in in the works – albeit slowly. After season 2, I had a whole list of changes I wanted to make and “design regrets” resulting from the extremely fast build season and required turnaround time I wanted to address. Really, I (and a lot of other builders) 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


that apparently ain’t hard

So that’s where we are now. The story of Overhaul upgrades actually goes back to right after Season 2 ended, and starts with what is basically the last large mechanical assembly that was designed, the clamp actuator…. meaning it was the most rushed and horrifying.

Ball screws were a bad idea. I was attracted too much to the promise of 90+ percent transmission efficiency, but they ended up being too fragile and also had the nasty habit of backdriving – made most obvious in my match against Beta. During the following 3-bot rumble with Sawblaze and Road Rash, the ball screw stripped out almost completely and began acting like an Acme leadscrew anyway.

Trust me, that hurts me viscerally to look at.

There was also a confounding problem with the actuator design and the clamp arm. In general, the actuator ended up too bulky to hide effectively without making the head ungainly. Because of the positioning of the motor and the bulkiness of the ball screw, I chose to simply add a little ‘horn’ to the clamp arm (the protrusion close to the pivot point) in order to protect the actuator motor from being landed on if Overhaul got flipped over.

In order to get the clamp running again quickly in case Season 3 happened relatively soon (*ahem*) and to explore the large Acme threaded rod market, I actually designed and machined up a retrofit using 7/8″ Acme screws and nuts – the odd size was for the easiest fitment to the existing actuator bearings, since the root of the 7/8″ Acme thread form required minimal machining to fit.

Also, I found the nuts on sale on eBay for like $20. There’s an engineering justification for every spur of the moment purchasing decision.

I wanted to redesign the whole upper half with a new acme screw based actuator to solve this. Furthermore, I wanted to move from a live-screw design to a dead screw one, where the actuator contains the mating nut within large carrier bearings and simply rides up and down a stationary screw, which is the design I’ve historically used for Überclocker.

The premise went from using the higher efficiency transmission option to the more durable and simple one and just overpowering the everloving fuck out of it to get my desired closing forces. As a large portion of combat robots revolves around the latter, it was clearly the way to go.

I cloned the Overhaul 2 CAD model into a new directory so I can start messing with everything. Here we go!

This is the actuator in its current position in the bot.

I wanted to try and see if I could move to a pull-stroke closing like Überclocker has been running. In general, the answer is “not really” due to how far the actuator will stick out into the ‘grabby zone’. In Überclocker, I sacrifice a whole lot of leverage to position the actuator almost vertically so it’s much more out of the way. I wanted to not make that sacrifice for Overhaul unless I had to, or if it were super convenient. functional requirement: be lazy

I also investigated the idea of flipping the thing upside down. In this configuration, if the trunnion tube is made non-offset (inline with the leadscrew) the motor will unfortunately hang down very low into the ‘grabby zone’ and be vulnerable.

All of this position testing though was enough knowledge for me to begin hashing out the next part of the design.

For now, I just imported the model of the P90X gearbox which was never quite implemented. Into the same model, I imported a bearing I bought on McMaster-Carr which I got curious about while specifying new thrust bearings for the this thing.

These are “one piece” ball and tapered-roller thrust bearings, so-called since McMaster usually sells thrust bearings in little kits of 2 washers and a basket of round things. Don’t be fooled, though… the “one piece” part is just a stamped sheet steel shell that holds the two bearing halves vaguely together.

The one on the right is a ball bearing based one, and the left one is a tapered roller bearing which is basically tapered the ‘wrong’ way compared to a normal one. This means it can support almost no radial load but a ton (or approximately 7 tons) of thrust load!

I found the tapered roller bearing one a little janky, though. The full roller complement meant it had quite a lot of drag when rotating, and the packaging was a good 3/4″ thick. There’s also no way I can reasonably use its 14,000 pound rating …. and that’s an industrial rating, mind you, meaning it will happily do that for thousands of hours and not just 3 minutes. So I chose to move along (for now) using the ball version, which only has a …. 7,000 pound dynamic load rating, but was thinner and lighter.

 

The brown object in the middle is a stock round Acme 1″-4 nut that will either be machined as a gear (quick modeled as teeth here) or have a machined ring gear shoved around it with a thermally-enhanced intereference fit (LN2 the nut, bake the gear, shove them together and run away fast)

You might be wondering what the plan for radial loads is, since ostensibly I have two thrust-only bearings designed into the thing so far. The fake answer is that the leadscrew nut, being bronze, will just ride in the stationary bore of the thrust bearings, since the magnitude of thrust loads will be much higher than potential radial loads on a stationary leadscrew.

The real answer is “yolo”.

Here I am playing with actuator positions again. The “pull-to-close” position in this photo mimics that of Überclocker.  I still felt that the important parts were too exposed here.

Another attempt just flips the actuator upside-down and exposes pretty much only the leadscrew. This was at least tolerable in conception – something being mashed into the leadscrew (which could also be shielded) might still leave me enough travel to get a good grab.

Okay, but what else did I learn from Season 2!? That if you leave something important exposed…. say, a master power switch or similar, and run on the assumption that the chances of something getting into there and causing damage are very low, then it will happen to you 100% of the time.

So I gave up the “pull to close” actuator position in favor of just trying to keep the leadscrew short and fat in order to maximize its column rigidity.  The bonus upside is it woud let me keep the existing center hub between the two arms if need be.

This positioning candidate was actually pretty favorable. I could see how the clamp arm geometry might be changed slightly to better accommodate it, and also permit it to use a relatively short leadscrew

Using the geometric constraints put forth by the toy component placement,  I basically wrapped an aluminum chunk around it. The cavities are for the gears and bearings.

I changed the design to an “embedded P80” to save length. The clamp motor is being moved to brushless, meaning Overhaul will be completely powered by questionable Chinesium. This time, since the Acme screw will not backdrive, I don’t have to hold the stick to apply pressure to the clamp arm any more, making it more Clocker-like in driving. Furthermore, this also affords me the opportunity to overpower the actuator while keeping a high gear ratio for force application. Überclocker’s current actuator is a regular 36:1 geared 550-class drill motor run at over 2x nominal voltage for moar powar – the short duty cycle of a grab and lift haven’t caused motor burnout problems.

A couple of different brushless motors could fit on this gearbox – right now, the SK3-6374 motor is in for modeling purposes.

Adding more parts and thinking about how to interface to the rest of the bot. The large rod-end is a convenient way to join to the wrist pin in the lift hub.

The design is more or less finished here. Those 4 square holes in the side are actually on a 2.25″ bolt circle, so four 3/8″ screws on each side will fasten the actuator to machined trunnion plates. I may end up making 2 of them dowel pins for shear strength and leaving only 2 as threaded holes.

With the new much more compact design, I was able to get a happy result for placing the actuator within the head. This was a good state to reach – I now have a solution where the trunnion bolt holes line up with the circular arc containing the patterned circular cutouts which Overhaul is known for. As a result, I can just hijack one of those holes (appropriately repositioned) as a trunnion axis, much like it is now.

All of this work occurred in the late December to mid January timeframe. I receive the new actuator billets and custom leadscrew nut back from my Chinese contract manufacturer this week.

In the next episode of Overhaul’s Improbable Overhaul Makeover?, I travel to Motorama 2018 with Überclocker in order to practice driving and strategy – and learn some disturbing new information which might disrupt my #season3 ambitions…

 

 

 

Charles’ CES 2018 Insanity Tour, Part III: Deck the Halls with Chinesium

chorl

Sup everyone! It’s now like a week and some after CES, and I clearly couldn’t be bothered to post about it as soon as I got back. Maybe it’s because I don’t get paid to write clickbait articles for the millennial divisions of aging news publications. Nah, I’m here to write postmodern shit-takes on the nature and origins of barely-functional demo products!

Or rather, I turned right around from CES and helped run the 9th-ever MassDestruction literally the morning I landed, and then proceeded to go back to launching my vaping company.


DIS YA BOYS YUNG MODULUS AND M.C. MASTER-CARR DA KING OF DA CHARLES RIVAH CUZ THEY NAMED IT AFTER ME

There’s an interesting story about that actually – I designed the new MassDestruction arena in the roughly week and a half before CES, leaving all my friends to scramble to build it in the week thereof, making me the most deadbeat possible dad. I went to Vegas to get shitfaced and party instead! Okay, to be entirely fair, I also scrambled to make sure the materials and supply/tool chain were in place, but they did all the physical labor – of which there was a lot!

I’d like to write up the full arena design pretty soon, since I think the construction technique was pretty innovative.

Back to CES! This post covers basically the adventures of Wednesday and Thursday, and is basically the extent of my exploration at CES minus a breeze through the “Normie Hall” (aka Central hall where all the huge consumer companies set up).  I was particularly excited for Wednesday, because I wandered the depths of what is basically Chinesium Alley:

 They called this the “Design and Sourcing pavilion” but really it’s where they scooch all the Chinese (and other countries, but China by vast majority) vendors. It was in a massive tent set in the south parking lot of the Las Vegas Convention Center. Inside is Chinesium of every possible composition you can imagine.

You know what? I can come to CES just for this and be happy. It’s not even an industrial/commercial trade show and there was this much Chinesium. Y’all know me – I skip right over the 8K fruit rollup TVs and smart toilets and prefer to see the behind-the-scenes clockwork instead. Like, seriously – you guys are an industry trade show, not open to the public, and I am an industry attendee who knows maybe just a little more than the public. Stop trying to sell me the magic.

If there’s one lesson that can be taken from my website (somehow), it’s probably that nothing is actually made of magic and even the best-planned products always fail in some way first. To come from an environment where I tried my darndest to have my students understand that, to one where the wool-pulling is not only expected, but automated and internet-connected with its own app, means I probably have a more abrasive approach to the show than most.

But the Chinesium hall was honest.

Maybe, uhh, a little too honest.

Possibly even blatant at times.

What I mean is the vendors here had no face to lose if if their pre-hyped smart home product failed to smart in front of an Afrojack concert knockoff and left their CEO a rambling mess on the stage. They brought products and services, and they were there to trade information if you were looking for it. If anything, isn’t this  what CES should be about?

(ok, not literally Maserati-stickered scooters, but you understand my perspective, no?)

Chinesium does beget some pretty Chinesium names, though. Some of them were pretty entertaining, including this one.

Chinesium marketing was in full force here too. So you named your three small outrunners after historical Chinese warlord kingdoms? What does this make the 150 and 200mm outrunners then!? We’re getting into some Yuan Dynasty and Mongol Empire shit now….

Silly scooters of all kinds abounded! Interestingly enough, there were some products I recognized from the main convention center floors. I wonder which came first…

This one in particular I can welcome, but the wheels are really and truly too small for the design, especially with those long forks. I actually walked up thinking it had no wheels at first and was just a frame, like a sample of what the company constructs for an OEM of the actual scooter. Nope – those are the wheels, the same 8″ generic scooter rims I’ve used on a dozen builds.  I’d still rock one though.

Some kind of Pharah Simulator. I didn’t wait to try this one, because at this point, I had already almost wrecked one VR simulator…

Yeah, I blame my van control loop being too tightly tuned. Notice how hard I try to cut the steering wheel multiple times, since Mikuvan, despite its most sincere wishes, is not a sports car and takes several turns to go lock-to-lock in either direction, and my experience driving in snow makes me near-automatically crank the steering wheel to quickly counter-steer as soon as I think a slide is beginning. The VR steering gear was much more sensitive, and also the lack of actual acceleration and body forces was confusing.

This was a great example of having to de-train yourself from something in order to be good at a nominally similar skill. I bet I could get used to the VR simulator if I had an hour or so with it.

This thing. Could I just get this as a simulator for real life? Ladies and Gentlemen, the U.S. Federal Government will not let me own and then operate such a device on public roads, and that is a travesty of justice and freedom. This is all the truck most of America actually needs. This object would handle 99.9% of my daily transit and hauling needs. Why can’t we have these?

(Okay, it’s kind of claustrophobic inside even for me, and I’m not that big, but my point stands)

This thing, too, was adorable. I wasn’t entirely sure what was being sold here – it didn’t seem to be the microcar-quadricycle, but a service or battery charging station. Either way, if you haven’t heard of them, these things abound in China and in some regions of Europe, such as France. They’re often driven by senior citizens, at least in the parts of China I’ve seen them.

Suddenly, WAIFUS.

Who would buy a Haru-chan mousepad for BattleBots #Season3 whenever we get around to it!? I have a supplier!

thursday

You’re not Mikuvan.

STOP PRETENDING. JUST STOP. YOU’RE NOT MY DAD.

Thursday was a sweep through the automotive displays in the central and north plaza where the autonomous driving demos were centered, and then also a course through the LVCC for the indoor automotive displays as well as the 3D printing and drones areas.  All of this touring outside can be condensed down to one photo of me inspecting the Byton Concept:


is that a bosch smg or are you excited to see me

Sadly, this model was a static display model – it had no drivertrain, just steel pegs to hold the wheels on.

The autonomous shuttle that got hit by a truck has returned! The whole outdoor demo area was one big “Buy Velodyne Stock NOW” advertisement. NVidia is probably making a killing right now – basically every single demo prototype uses NVidia gear.

Inside the automotive area of the LVCC – there were a lot of future spacecar concepts being shown here. This is the Toyota booth, whose displays were quite cheery and festive. I guess it’s at least someone’s birthday who walks by, so maybe they’ll be inclined to believe that Toyota already knows everything about them!

All I can think of is why would you put a screen exactly where the bumper should go???

I’m really bad at this “future of automobiles” thing. I maintain we need a return to the days of prismatic vans.

I took a creepshot of the actual Byton Concept model with drivetrain gear. Sadly, it’s skid plated all the way, so there’s nothing really worthwhile here besides “Yeah, it has suspension links”. I was then chased away by one of the booth operators, who directed me to a powertrain engineer to answer all my questions instead of trying to perform live industrial espionage to find out.

I learned from Mr. Powertrain (who clearly doesn’t believe any of his own company’s marketing) that the running gear is all Bosch, including the inverter and traction motor, and the batteries are prismatic LG Chemical modules.

Overall, this reinforced my idea that the car itself is very generic and lego-blocked, and that the company more emphasizes the lifestyle and the ａｐｐ　ｅｘｐｅｒｉｅｎｃｅ.

nice corvette

This is the Fisker eMotion. The relation betwen all the parts of Fisker is too complicated for me to understand, but this is basically zombie Fisker’s new product, created from scratch after the failure of Fisker Automotive. It’s not to be confused with….

….the Karma Revero, which is a relaunched Fisker Karma shaped object using the previous bankrupted company’s IP and assets.  What?! Okay, on this episode of fancy spacecar family feud….

Y’all aren’t vans. I know it’s “easy” to make a high performance EV these days, so I’m just waiting for the chance to do one up  myself because it doesn’t look like any of you guys are going to.

YOU’RE NOT A VAN EITHER. But you’re close! My favorite whipping child of the Silicon Valley automotive startup industry is now parked in front of me! This is a real live Faraday Future FF91, in Matte Black.

Faraday’s had a rough year, so they didn’t even have a CES presence besides this one unit giving test rides. Wait, test rides!? I waited about 45 minutes after hearing this on the Internet at where they were staged, at the Renaissance Hotel immediately adjacent to the LVCC.

Nope, press and VIPs only. It turns out I was neither one. Who knew!? Anyways, I rag on Faraday a whole lot, but I would like to see this thing become a production model even if (and I prefer it this way) it ends up outside of any kind of lifestyle ecosystem like the kind Byton is trying to stir up.

And if not, I will try my hardest to be at the liquidation auction.

And that’s it. There’s no lesson or takeaway for me from CES. It was great to see where the industry congregates and get a look at a lot of the startups. Many companies are vying for the chance to entertain only a few markets and industries. For me, the joy of CES (besides the days worth of Chinesium) was more like… seeing everyone’s different (yet similar) approaches and takes on appealing to their mental model of their customer base.

I like to think that my two or three product lines were very successful at hitting my target customers,w ith RageBridge2 now basically a standard in the robot fighting world, Brushless Rage sales going quite steadily, and somehow moving several thousand Hall Effect sensor rigs already in the past 5 years – seriously, I never expected to sell them past roughly 2013-2014, but a few go out every week! Then again, I’m also not on purpose trying to become a multi-million or billion dollar company, so my priorities are different.

Back to your normally scheduled robot content hopefully soon!