Category: Bots

Any posts about the robots!

Returning to the Game With a New 30lb Featherweight: Candy Paint and Gold Teeth

chorl

My mental design-year can be broken up into roughly two halves: Dragon*Con season, which spans from roughly March to August, and Motorama season, which is basically September through the next February. Of course, the observant would notice that these things seemingly coincide with robot tournaments.

But that’s kind of how it works. After each big event, I start thinking about what I want to do for the next. Robot fighting is a game which I do not foresee getting old for me for a very long time to come. And why should it? Of all the things I ever became involved in, besides being the first one over 12 years ago (…) , it’s the most freeform and unburdened by pages and pages of rules and procedures. Run what you brought, not what the organizers say you have to bring. It’s very much a high-energy (… literally…), destructive, and kind of redneck sport, and there’s no whitepaper to write at the end. I have literal dozens of sketched out designs that will likely never see the light of the day unless I drop everything and become a professional robot cockfighter, which I would love to do. Here’s just one.

 

Someone get on that right now. Build it so I can live vicariously through you!

But I digress. It’s been Motorama season for a while, and so my off-duty mental cycles have been devoted to engineering the latest entry in the Imperial Carolingian Robot Army’s Register. May I present CANDY PAINT & GOLD TEETH:

 

Wait a minute. Hold on, trap. That’s a giant spinning weapon, not a fancy multi-axis grabby thing. The hell is wrong with you?

I’ve  been out of the high-energy spinner game for quite a few years. My last “large” kinetic weapon was Trial Bot, all the way back from 2005-2006. That design wasn’t very effective, so it was retired after only one event. I’ve built quite a few successful weaponed 3lbers such as Nuclear Kitten (and its earlier versions), plus Pop Quiz which was successful Back In The Day. Overall, I haven’t been enamored by the big spinning chunk of steel like many competitors have been, choosing instead to focus on drivetrains and manipulator type weapons like lifting and grabbing weapons.

With the flooding of the hobby R/C marketplace by Chinese components some time in 2004-2005, the spinner game began getting ridiculous, with each wave of new bots combining a larger brushless motor with a larger hardened steel weapon of some sort. The arms race began being lambasted as the “brushless penis race” as most of the competitors were young men, and most of the successful designs were the same in concept and execution, only differing by how big the spinning toothed drum or bar was.  It got to the point where many matches were just a minute of robots hovering around each other, each aiming to deliver the match-ending hit, and finally a weapon-to-weapon hit that destroyed both robots or left them totally disabled to the point of only being to crawl around on one wheel.

It was, to borrow a previously used analogy of mine, like we were all dubstep groupies waiting for The Drop… or in this case, The One Hit. The only other bots that could survive were armored bricks which kept running into the spinner until something, one or the other, broke. I did not find this game very interesting, and ultimtely neither did quite a few builders, who began exiting the game after their last bots were exhausted, because it was getting expensive to rebuild over and over robots which were good for only a handful of matches, or even just one. I in fact retired Test Bot out of the 12lb class after it was “penised” at Motorama 2008. That year also saw the first Überclocker.

Several efforts sprung up to counter this, including the Sportsmans’ Class which I found as slightly reactive but ultimately aligned with my own goals of repopulating the ‘middle of the spectrum’. Back in the very old Battlebots days, the power to weight ratios of entries was so low that matches were more determined by driving skill, strategy, and reliability, than dancing around gyroscopically waiting for the right impact to land. This greatly contributed to the corpus of weird or interesting designs (check out the old Team Nightmare event pictures). In the current Sportsman’s class, flippers, hammers, and the odd clamp-and-lift or two (ahem) have all returned. The matches tend to go the full length and feature a lot of action and driving, with the added bonus that you could generally return home with something that did not require a dustpan to pick up.

It’s been a while, however. I miss the feeling of beating something with a chunk of steel. That’s where this design comes in.

There’s been relatively few successful overhead-bar spinners, known in the vernacular as “Hazard-style” after the multi-time Middleweight Battlebots champion. This type of design is hard to get ‘right’ because the blade tends to destabilize the robot if it’s too long or heavy, and then it’s more difficult to self-right if it does go over. Pop Quiz and Trial Bot are both this style of bot, so I have a historical attachment to this design too. Other examples of this design are Brutality

and Tornado Mer, which early versions of this design resembled the most.

Note that all these videos are from quite a long time ago.

I wanted to try making a bot that wasn’t square. Using a continuous round tube for the outer armor was appealing because it presents no obvious weak spots, unlike a square corner (or the backside of Brutality’s front wedge). I fixed the blade size at 2 foot span, 3″ wide, and 1/2″ thick, a relatively solid dimension that ended up being  almost exactly 10 pounds in steel. This dimension has been my ‘default’ go-to for a weapon of this size. A chunk of S7 tool steel typically costs about $100 in this size. All things considered, this thing was basically a small Tornado Mer.

The design goals for this bot were basically:

  • Be round.
  • Be reliable, over packing sheer energy

I started with the “doodle assembly” in which I haphazardly make parts and outline sketches.

 

 The size of the bot was dictated primarily by what size giant tube I could easily find and purchase. Yarde Metals had a few promising candidates in the form of 15″ and 16″ tubing, so I started with 15.  The rectangles represent the outlines of components I wanted to use. At this point, the choice of drive motor was a set of Banebots P60s with some 500-class DC motors. Fairly vanilla, and would give this bot an average drivetrain power for a heavy weaponed 30lber.

I experimented with several different possible heights, shooting for a 1.9″ blade height: 1.5″ wheels, 3/16″ ground clearance, and then a little over that to make sure I don’t whack myself. I’m used to sacrificing COTS parts for smaller packaging – Pop Quiz is still one of the lowest blade height antweights extant and for a while was the absolute lowest, and Trial Bot also had a blade height of 2.2″ using 2″ wheels.

The robot height decision was tied in with what I wanted to drive the weapon. Initially, I was inclined to make a super-wide custom direct-drive motor for the weapon – which would turn this bot into a giant Pop Quiz. One plan was to start from a chopped quadrotor motor on Hobbyking, except add external ring bearings (or metabearings – support rollers) to make it stiffer. I also took apart the 8-FUN motor again to measure the stator and considered using the motor inside as-is.

Further thinking and discussion led me to go for a brushless scooter style high-reduction indirect drive. I figured this bot was going to spend a lot of time upside-down and possibly crammed into a corner. A direct drive motor wouldn’t be as deterministic in such a scenario unless I also ran a sensored controller and used Hall sensors, which I didn’t want to do for reliability’s sake – one more part to jostle loose or break off its solder joints. The first image still shows a pretty insane and almost impossible (due to lack of tooth engagement or minimum pulley radii) and unnecessary 10:1 reduction. I put in a ~85mm motor diameter as a placeholder, since it was pretty clear that this had to be a custom job.

More components have been added here, including the outline of a Ragebridge as well as batteries. Height was the most important criterion when choosing batteries for this thing, since I would only have about 1.25″ of space to put them in. I elected to run an 8S power system with two 4S packs wired in series. My voltage philosophy is generally to run as high of a voltage as I can reasonably do so to minimize current draw and wire size; 8S was about as big as I could get without dangerously overvolting the average 12-18v RS550 motor. This high voltage would allow me maximum flexibility in choosing the weapon motor winding to best match it with the physical gear reduction.

I ended up deciding not to spend another $100-150 on batteries, but to use up more of my Nuclear Arsenal. I was going to split up two Thunder Power 7S 4.4Ah packs to make two 4S ones – two of them have dead cells, so they are not useful by themselves any more. 4 cells from those packs gives me a pack 30mm tall, or pretty much my maximum allowed height, as well as a great deal of battery energy for match length and number-of-spinups overhead.

The reduction is still shown as a slightly less ridiculous 8:1. I was also settling on what kind of power transmission to use:

  • It needs to not stretch – or at least do so minimally, for consistent power transmission properties
  • It should be rubbery, ruling out chain drive. A metal to metal coupling would be kind of asking for breakage.
  • It shouldn’t have teeth, because the high ratio I needed implied a small pulley, tight wrap, and therefore high tension in the belt; plus extreme impact loads.

I decided to give good ol’ V-belts a shot. V-belts often get written off as old technology, but they have favorable properties for this sort of thing – they allow some innate slippage due to the lack of teeth and do have tension members (they’re not just loops of rubber). The “L” series of belts (2L, 3L…) held promise for me since they’re designed to be small and flexible. A 3L belt seemed the best candidate here – 2L belts are tiny (1/4″ wide and 1/8″ thick!) and 5L is getting on up in huge. A 3L belt is 3/8″ wide and a little over 1/4″ thick, and the empirical smallest-pulley in use seems to be around 1.25″. Many larger bots have (and still do) use them for weapon drive, but they are not common in the little bots usually because of the minimum pulley diameter and thickness.

So naturally the next thing to get modeled is the Epic Drive Pulley. This shows the next weird thing on this robot that’s been getting me some stares. I’m electing to go for a live (rotating) axle suspended in dual tapered roller bearings rather than putting a hub and bearings on the blade, and only having a solid pole on the robot.

The latter is a mechanically simpler system, but in my opinion a live axle in this case saves both weight and height. With a hub and bearings that stick up above the blade, the center of impact force reaction is far up the shaft, which needs to be large in diameter and mounted solidly in the center of the bot to handle it. If I’m going to have a big solid block in the center, then I can put bearings in it instead, and move the center of impact much lower as a result. I also lower the blade height substantially doing so.

The big pulley is actually going to take up a substantial portion of the underbody real estate of the bot, since it’s on the other side of the bearings (to save, again, blade height). A lot of components need to fit under it, which ties into the 1.25″ of available workspace issue I raised earlier. This is what the blade spindle assembly looks like, in section; excuse the CAD-ahead going on:

Note the presence of Belleville washers on the top and bottom. These are often used to preload tapered roller bearings for zero-slop operation. In this case, I’m using the bottom washer for bearing preload (it pushes the bearings together, against the shoulder at the top) and the top big washer is only to keep the blade on. This keeps the bearing preload nominally separate from the preload of the blade. The idea is that the preload force has to be overcome before any of these parts even think of moving, and with (hopefully) most of the impact forces being side loads, it should prevent “blade wobble” from shaft compliance.

Now, in a good hit, everything will probably just munge together, but hey.

Back to the proper CAD order:

The internal frame rails were made using a “master sketch” that I reference all the solid models from. At this point, I didn’t know what any of the spacings or sizes needed to be, so I could just adjust the master sketch and the rails would resize to fit. The first time I did this, I made a sketch in the assembly; turns out Inventor doesn’t allow those kinds of references.

So I had to start over and make this sketch in a separate part and the insert the part into the assembly, letting other parts become Adaptive off of it. End random Autodesk Inventor tip.

Whoa, getting a little ahead of myself here.

After liking where the rectangles ended up, I began importing parts from previous robots and inserting them. The P60s are shown, as is the drive wheel solution: Banebots wheels on custom hex hubs, running on shoulder screw dead axles. I’ve never used Banebots wheels before, but they seem to be solid for a lot of other builders. The available of a hex bore was the swaying decision here, since it reduced the “hub” to a chunk of hex steel with a few retaining ring grooves cut into it.

To get power from the offset motors to the wheels, I have one stage of very short chain joining the motors to the rear wheels, and then another 1:1 stage from the rear wheels to the front wheels.

At this point, the protoform of the weapon motor has also been modeled for visual fitting.

This is the motor in a more complete form, though still showing the unrealistically sized 0.9″ pulley. Basically a one-sided hub motor with an integrated pulley, I’m going to blast it out from a solid round. No, not a two-piece welded assembly, nor a stack of waterjet-cut rings. I have a 3.5″ steel billet that’s been sitting around for far too long.

The magnets are the same ones used on the first iterations of Razermotor, sourced from Supermagnetman. The stator is also a leftover from the RazErmotor days, a 70mm copier stator that’s 15mm thick.

It sits on a 8mm shaft that rides in conventional 608 skate bearings. The very short load-to-bearing distance makes me confident that a good quality 8mm shaft (read: not made of the bullshit I make standoffs from, but real shaft steel) is sufficient for this motor; it’s also going to be hitting 12 to 15,000 RPM, and a bigger bearing would suffer.

A pizza appears.

The motor mount has a gratuitous number of slotted holes to let me adjust the belt tension if needed, but also maintain rigidity in the area.

This bot is of an ‘upside down’ construction. The top plate is rigid and integrated into the one-piece frame, and there’s only a bottom ‘dust cover’ which will be made from 1/16″ FR-4 (Garolite) laminate for the electronics. The batteries will have a bracket to retain them, but this is not shown yet. Basically, not a good idea in the old Battlebots days of floor-mounted hazards. I went this way because I didn’t want to have to remove the blade over and over to do maintenance. Everything in this bot drops in from the bottom and is bolted in place.

I also went to ‘duallie’ Banebots wheels because the single 0.4″ wide wheel seemed too fragile. These wheels have a thin web portion before they fatten up for the hub again. The chances of the bot landing on one side (or one corner, hence on the wheel) and breaking that off seemed fairly high. What I’ll likely do is put the two wheels side by side with filled epoxy in the middle to fuse them permanently into one.

A view from the top with the top plate made transparent. Buttonhead screws are shown, though for blade clearance issues, these must necessarily be flatheads in real life.

The design stood like this for a few days. I was satisfied with the roundness, but did not like how much wasted space there was inside. I needed to match the largely rectangular parts inside with a circle on the outside. I guess that’s just a trait of round robots.

After a while, though, I decided to refactor the design into one that was more practical. The roundness makes the bot more visually cohesive, but it is not very practical. I wouldn’t be able to push very well as a last-ditch backup, and being fully round is counterproductive for self-righting – a lot of it depends on luck and physics from jouncing around on-edge. A fully circular bot like Tornado Mer tends to “coin” around (though in that match it didn’t help that the weapon motor contactor locked on…)

I started playing with adding indentations or other features to the design:

Attempt number one: Cut off a chunk of the circle and append a polygonal wedge to it. Simple enough, and it would get the job done, but I didn’t like the fact that the two end corners were exposed. Sharp internal corners on this design would present an unnecessary vulnerability to opponent weaponry, since it would otherwise tend to bounce off the round sides or up the sloped wedge surface.

So I tried a ‘wraparound’ wedge instead. The wedge is not formed to the rounded surface at the corners, but is just tangential to it for a duration. This seam will be welded shut so it will resist peeling.

I liked this design a whole lot more, so I went with it:

Five front gussets support the wedge. I had to rebuild most of what was the rear end, including new cover plate shapes and motor locations. The battery cage has also been modeled – it comprises two 1/16″ aluminum folded sheet metal assemblies that each trap one modified 4S battery pack.

I decided to change out the motors entirely. Previously, I was planning on running a single-stage 5:1 P60 gearbox; however, their length and mass became issues. Plus, I’d have to buy them. Taking a page from 12 o’clocker’s “Angerboxes“, I modified the design to mount from the top down. The drill gearbox is a 6:1, yielding me a little reduction, so I could back down on the need to externally reduce from the intermediate chain stage. The simpler design saves a few ounces per side. Even though they’re plastic-cased, I think a well-supported motor (see the black rear mount) and use of the material in bulk will be sufficient.

The drivetrain is designed to hit 15mph, which is pretty zippy for a heavy weaponed bot.

A size comparison next to Überclocker, which it would bang up pretty badly. Clocker is a pretty good example of a design with too many pointy bits to survive in a big-weapons environment. At the very least, the clamp arm would have needed to be more vestigial to allow weight for a big armored plow in the back.

Physical progress-wise, I’ve accumulated the majority of parts for the bot, and more are on the way. First, a few weeks ago, I snagged these old weapon blades from a lightweight (60lb) bot which were reused in a 30lber years ago. They are…. 24″ long, 3″ wide, and 1/2″ thick, heat treated S7 tool steel with 1 inch bores. Exactly what I was designing! Well, that pretty much seals the blade decision.

The bottom one is solid, weighing 10.2 pounds exactly as it should, and the top has been weight-reduced to around 8 pounds.

I should be able to run the solid one; as-designed, the robot weight is 27.6 pounds, not counting some small hardware and wiring (which always adds up).

Most of the frame parts cut out of 1/8″ and 1/4″ aluminum. Caveat: I’ve only welded aluminum once and it didn’t go over too well. This will surely end well.

A few pieces are missing, so I can’t start just yet; I’m hoping to wander into the machine again this coming week with more parts for other bots.

However, I did sand and fit the rest of the pieces together. Pretend-o-bot #1 is complete!

I’m hoping to be able to roll the big outer hoop this week from barstock. I purchased two 1.75″ wide, 1/2″ thick 5 foot extrusions to make the hoop – only one is needed, but it was cheap and I’m most likely going to bang it up at least once.

I’ve been probing the local peer cloud to see if there are any skilled aluminum welders willing to take this job up. As much as I would like to learn on this bot, I also kind of don’t want to have it shatter on the first hit! If not, or if I’ll have to pay an absurd amount to get it done, well… here goes nothing in particular.

I’ve also gotten:

  • The first boatload of McMaster hardware
  • Motor magnets
  • A pile of Banebots wheels, since a full set of wheels plus spares on this thing is like 16 wheels.

Parts that are already on-hand and just need to be modified or pressed into service:

  • Ryobi drill motors. I purchased these from a parts distributor (p/n 984572-001) on the recommendation of a few veterans of the community. These are basically Harbor Freight drills but much higher quality.
  • The 7S 4.4Ah Thunder Power packs with dead cells, to be reworked into 4S packs
  • The copier motor stator

I’ll still need to machine:

  • The one-piece rotor for the weapon motor
  • The stator mount for the weapon motor
  • The epic block of bearing-holding at the center of the robot

As for the giant output pulley, I did a make-or-buy study as soon as the design was finalized: I threw it on MFG.com, my go-to for hiring shady Chinese job shops to machine things for me (things made through them include all of the DeWut gear and my small run of hub motor parts). I will hopefully have the finished result back by the end of February – but if shit goes down, I’m going to cut out a circle from 1/2″ plate, stick it on a mandrel, and go to town.

In the next episode of Big Chuck’s Automotive Blog…

 

The Dragon*Con 2013 Complete Roundup, Part II: Event Recap and Maker Resources

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So here we go – now that Part 1 has had some time to sink in, and now that my shop is looking remotely functional again, it’s time for some part two. In this section will be the two new ‘sections’ (carried over from part 1):

  1. Operation GIVE ME A BRAKE: Brake system and inspection all-around on Mikuvan!
  2. Pad Thai Doodle Ninja, an Antweight 4-bar pushybot I designed and built in like 72 hours!
  3. The trip down, the con, and how the bots did at the event!
  4. The links and documents associated with my two panels at  Dragon*Con.

This semester, the two fabrication labs I oversee in the MIT-SUTD Collaboration is once again playing host to How to Make a Mess out of Almost Anything:

Yeah, it’s going down about like that. Unlike the last two academic terms (January – August, basically), I’m not “running” a class this term, so it’s going to be way more chill. I’m not sure if I will want to run back-to-back design classes again like the consecutive 2.00gokart and “2.00GLP”, since the overall level of intensity and chaos is extremely high. I see how the department can go through design class professors rapid-fire now.

Anyways, back to the trip. It’s Tuesday night! Time to load up robots.

Dragon*Con 2013

…but first, I need to get my 200 pounds of tools, accessories, and spare parts out of the back. I left a spare tire, van-specific tool box (like my robot-specific toolbox, but everything is bigger!), and spare fluids. The floor jack was removed since there is a bottle jack for tire changes in a rear compartment. Basically I was purposefully blocking myself from doing any roadside extensive work – I think I’ve gotten everything mechanically to the point where a failure necessitating deep dissection is practically going to be catastrophic in nature and not something I’m going to do in a parking lot.

Replace all the van kibbles with robot kibbles. I guess I could have kept the van kibbles in the back anyway, since I was initially expecting more bots and parts. This stuffing was, consequently, not as epic as the Motorama Stuffing or the Last Dragon*Con Stuffing (though those vehicle did have less hatch space to begin with). The ship-out time was essentially midnight.

Around 4, we reach Flushing, New York, where Xo Has Joined Your Party. This is where the trip got a little more interesting.

In 2007, before I was a wee bunny at MIT, my parents and I drove up to visit the place. We took I-95 in all of it’s forms through DC, Baltimore, Philadelphia, Newark & New York City, then up through New Haven and through Rhode Island. My only memories of the trip are of how I-95 was utterly depressing in every way, from tolls to traffic to construction, and the general level of suck the Northeast urban cluster exhibited.

Six years later, I was meandering up the Bruckner Expressway in the wrong direction when I hazily decided that maybe I-95 wasn’t as bad as I remembered. Plus there was like an exit for it right there and if we kept going semi-lost I’d end up back in Connecticut. So, down 95 we went, across the George Washington Bridge (slowly, because construction and late night truck traffic), and down the New Jersey Turnpike, the fancy Delaware Bridge thing, then down onto Baltimore and onwards.

I’m glad to say that 95 is every bit as depressing and repulsive as I remember it and that nobody venturing out of the Northeast to anywhere should ever drive on it for any reason.

All together, I think between Queens and Baltimore I busted $35 on tolls alone, not even including the relatively minor tolls in Massachusetts. Every bridge or turnpike had its own toll authority.

I thought the Interstates were supposed to be full of FREEEEEEEEDOOOOOOOOOOOM.

In the Baltimore-Washington area, I stopped at my favorite IHOP in College Park, MD. This has been the focal point of several Otakon trips. South of Baltimore, we hit what I like to call “Facebook traffic”, where congestion is so bad and traffic is so stop-and-go that everyone is on Facebook complaining about it. This took about 2 hours to sit through because we came in at the exact time to hit traffic in both metro areas. How are you actually supposed to get to work?

We hit Atlanta around 10PM, for a trip duration of essentially 22 hours, many of which were spent fucking around with the abomination that is 95 in the Northeast Corridor. For instance, it took about 45 minutes to even get out of New York. Then factor in the fact that the cruising speed of my lovely pallet of cinder blocks was about 65 to 70mph.

The next day, it was off to the Invention Studio to get the band back together. Here’s the vansnexttothings.tumblr.com shot of the trip:

We journeyed a little off campus to get lunch, and in the parking lot of the local small sketchy college restaurant cluster was an Audi R8. Like most expensive cars, it was parked “haphazardly”.

This year, since I brought actual working robots, and because Pad Thai Doodle Ninja was completed the evening before the con really kicked off, and because I wasn’t trying to speedball an entire new bot in 3 days,I got a lot more wandering and people-watching time. I was especially tuned to try and find people with costumes that looked like they required some amount of mechanical construction or engineering (see my brief on this last year).

That, and giant Totoros.

Here’s a good example. This funky gun-like prop had a ton of lovely CNC aluminum work. The wielder, though, wasn’t the builder.

I spy a little of waterjetting on some of those interior parts!

The thing I’ve historically liked the most about Dragon*Con over other gatherings is that there’s no particular theme. The con covers about every niche of culture, up to and including robots. You’re not even going to find that at PAX or Comic-Con. This enables people to mash together different story universes and characters with much more impunity, for the amusement of all… such as Portalmau5 up there.

I’ll be honest – this is pretty much the only reason I went to the actual con for, besides my own panels. No, not just any group of girls in costume (that’s so last year), but specifically one series. The latest thing I’ve been fanning over is Monty Oum’s RWBY, also known as “Charles has to build shit that Monty designs with ill regard to constant-volume systems”. Most of the characters are Action Girls with giant mechanical transforming weaponry – what’s not to love? The thing that hooked me at the beginning was the RED preview.

The series so far has really pinged my “defer judgement” sense, since to me it seems a little hurried plot-wise and is seemingly laundry-listing TVTropes (site left unlinked because I don’t want to sink everyone’s productivity for the next 11 days) on purpose. But I’m proud of my ability to cherrypick favorites very specifically, so I’m still into the series for the giant mechanical transforming weaponry.

The series is so new that I wasn’t sure if anyone was into it enough to plan costumes, and I wanted to get a sense of what is already out there in terms of mechanically actuated versions. Conclusion? Zero. On the internet, and in real life at the con.

That’s where I come in.

…not right now, though. With Saturday winding down and the Robot Microbattles just around the corner, it was time to intensively practice driving. This was the remains of a laser-cut quadrotor frame that everyone’s 1lbers and 3lbers were beating on throughout the evening. I also repaired Colsonbot by printing a new motor mount carrier and replacing a stripped drive motor.

This year, Microbattles got the entirety of the International ballroom at the Hyatt Regency Atlanta. In past years, the event has only gotten half the space, and the audience had to be capped every time. The event size is now on par with the main Robot Battles, with even more entries.

So many, in fact, that single elimination had to be used for the tournaments again, and we still ran overtime. The event has been running against its time limits (and beyond them shamelessly) for the past 2 years, and this year was no different. Hopefully the D*C planning committees finally recognize this.

The Atlanta arena returns! This year, an actual 12″ sanding disc was mounted on the spinning turntable. I’m glad to see that my contraption is still functional. During the event, it produced quite a few light shows from bots being stuck in the hole, and reduced the diameter of a few wheels.

The usual suspects were in attendance. Here’s the table of G3 Robotics & Variable Constant & Guy Who Never Updates His Website.

This is a reasonable approximation of the audience during the day. The added seats and projection screens helped crowding immensely. Because the arena has a pretty high bumper rail (3″ or so), and it’s up on a stage, you can’t actually see the bots from the audience unless something exciting happens, so it’s entirely dependent on the video crew!

microbattles results

Because the Antweight tournament was single elimination, sadly Pad Thai Doodle Ninja only got one match in, against the veteran Segs (pic from years past, to the left). Cynthia put up a valiant driving effort, but the lack of “lifter lip” on the arm meant it had a hard time getting under Segs, and the bot was twice as slow as originally planned.  Near Chaos Robotics, filmer of events, recorded the match in two halves: Part 1, Part 2.

In the rumble, PTDN got into the thick of it and pushed a few people around, then got pinged a few times by DDT. The lifter arm was bent up,  but the bot otherwise had no permanent damage and still drives.

Showing why extending the front armor to the floor might be a bad idea – check out the crimps on the left side. After the DDT damage, the bot had trouble maneuvering on the floor.

Rear view of the damage. Because DDT pinged the arm while it was partially up, the force ripped the rear link out of the arm. That part was extremely thin-walled to begin with and should have been thickened, but I was afraid of it interfering with the robots’ self-righting. Turns out that wasn’t a problem.

I do want to fix up PTDN and upgrade the drives to the original 10:1 spark motors I had intended, and redo the front armor. The lifter servos will either be consolidated into one higher torque metal gear servo, or two digital servos for better range matching.

Colsonbot, sadly, was unable to colson much because of the unrepaired damage from Bot Blast. The “duallie” O-ring wheels were beginning to come apart, and the O-rings tended to slip off and get caught between the shell and the bot. It survived the event pretty much unscathed, however, and I don’t intend on making any big changes to it save for remaking the wheels into single-o-ring affairs that have more ‘stretch’ on the rings themselves to prevent them from twisting out. Colsonbot got in one match against Radiobox, and also the Beetleweight rumble where it was mostly a stationary arena hazard.

big bots

Back in the Invention Studio on Sunday night, preparing for some final tuning and drive testing. Null Hypothesis had to have a drill motor replaced, but otherwise, I didn’t have to do anything to the bots for once.

At the event, while I was testing Null Hypothesis on the stage, it randomly blipped and stopped moving. The cause was traced to the controller completely losing its gate drive power supply for some reason. Whatever the case, it necessitated an in-field replacement, which Adam is handling.

Most of the builders are seasoned & flavored veterans, but there were some rookie builders this year. It’s good to see the sport grow organically, if not somewhat slowly. This bot is an alleged 12lber – according to the builder, it weighed 14 pounds when finished. Oops! And hence, it was named. It ran without any top armor at all – something which ended up causing it to lose to 12 O’Clocker.

Omegaforce returns, with more unique wedge attachments. The outer and inner wedgelets are linked together in such a way that the outer set lifting upwards for any reason causes the inner set to drop down to the ground. The upper wedges can swing all the way backwards. So it’s a multi-tiered defense system against oncoming opponents. The actual functionality was a bit spotty.

Non-rookie builder (I met Miles at Motorama 2013) but first Robot Battles event. The center of this bot was supposed to be a lifter, but some things didn’t happen in time. And yes, it’s entirely made of wood. I was hoping to face this with Überclocker, but didn’t get that chance.

Another rookie bot that was supposed to have an attachment in the middle (in this case, a hammer) but Stuff Didn’t Happen.

Überclocker 30 charging before matches began.

12 O’clocker after its first match, which I won. I learned that the springy legs worked well, but they were not well constrained downwards and could get pushed to the point where the front wheels of the bot were propped off the ground. The contact point they make with the front axle standoff should probably be modified to capture the leg in either direction – up or down.

This is probably the most quintessential robot even picture I’ve ever taken. Equipment all over the table, Mountain Dew everywhere, and “beasting food” as I like to call it strewn about.

 

I try to post audience pictures of Robot Battles every year, because it really is a phenomenal show. I think the audience averages 5 or 600 people and can peak near a thousand. In quite a few years that I remember, the hotel had to deny people entrance because it became standing-room only and exceeded the allowed occupation of the room. Here’s the right half of the audience…

The center…

And the left half.

Oh, this was before matches started.

results

I’m extremely proud of the bots’ performance and reliability this year, as well as the show they put on. For my 10th (!) Robot Battles it’s quite refreshing to have things that worked. The robots ended up losing only due to my own mistakes, or my tendency to favor a good show over winning at this event. I actually can’t bring myself to just drop someone off the edge cleanly with the Clocker pair, and this did bring about my own downfall a few times…

Regardless, Überclocker 30 got 2nd place in the 30lb class, fighting Null Hypothesis (oops…), Overthruster , Null Hypothesis yet again, Jaws – probably my most favorite Clocker match ever, Overthruster for the nth time, and finally losing again to my eternal nemesis Nyx. Overall record of 4/2. There were sure lots of reruns this time around. Clocker was a crowd favorite in the past, and now even more so since it works pretty reliably. At the very end, during the rumble, I did lose the drivetrain completely, most likely due to the solder joints breaking off the motors – this has been a weakness of the bot since Motorama ’13 that I forgot about until now.

12 O’Clocker finished what essentially is 3rd place, since the winners’ bracket finals loser and the losers’ bracket finals winner were the same bot. In the final match, I just got plain outpushed by a more powerful and faster opponent. 12 O’Clocker was also a crowd favorite, possibly more so than Überclocker itself, if I could judge the audience well, and went 3/2.  12 O’Clocker’s match videos: Tetanus Shot 1, Oops, Omegaforce, Apollyon, Tetanus Shot 2

So what’s next for the robots? Besides the odd demo or sparring match, it’s time to make the upgrades for Motorama 2014 next February. Überclocker’s current form debuted this past February at Moto ’13, and I don’t anticipate making any changes to it at all (except for actually using the Quick Disconnect style terminals on the Dewalt motors, maybe…). The new actuator on Überclocker’s clamp worked as I expected – I could grab and hoist up opponents very quickly, and the multistart leadscrew eliminated the binding it was prone to perviously so I no longer had to be gentle with the stick – RageBridge took care of the “endstops” by entering current limiting mode. On 12 O’clocker, I want to better secure the front legs, but otherwise, the bot incurred no damage from this event.

the way up

I decided to be intelligent and finally take a route which I’d been eyeing for years, but never dared try for some reason until now:

In my opinion, this is the most direct possible shot through to New England without going near any metropolitan agglomerations. The plan was to detour north at Charlotte, NC. and follow I-81 all the way up to Motorama Harrisburg, from whence my general solution has been to go east and up-around New York City through 287, then cutting north out of CT on I-91 and I-84. The upper half of this has been tried and verified many times.

I think this was a good decision. Not only was it smooth all the way, but the western VA and NC scenery subtracted from the boredom greatly. We passed through, and stopped in, a few small towns and villages nestled in the Appalachians, places that I’m sure high flying urban folks around here don’t give a shit about. It was, in my view, a more authentic American experience.

Stopping for a fuel and breakfast somewhere north of Roanoke, VA.

daily van bro

I saw something which looked out of place across the street at a convenience store. Turns out it’s a Greenbrier, one of the original American compact vans built to compete with the VW bus! These are rear-engined, just like the VW bus, but the Ford Econoline of the same era was mid-engined and rear wheel drive, and the layout was directly ported and evolved by the Japanese. So, really this is an evolutionary ancestor to Mikuvan.

It was also on sale. I called up the seller, but sadly the price asked was out of what I had in my pocket at the time. If I were into these things, though, it would be a very fair price for a vehicle in as good visual condition, and as good running condition as the seller described.

Compared to almost all modern cars, I’m pretty damned small, but the Greenbrier was somehow even smaller. And it had 3 rows of bench seats.

The rest of the trip up through Harrisburg and beyond was pretty standard. We arrived back in around 1:30 AM (that is, 0130EDT Wednesday 9/4). And so that concludes Dragon*Con 2013. A pretty delightful adventure filled with working robots and now-most-definitely-working vans.

Well, okay, I did have to rebuild my A/C blower motor again, in the Georgia Tech parking lot. Remember those brushes I installed? They were backwards, and they ate through the copper bus wire after a few thousand miles. A random 200W scooter motor turned out to have the exact same size brushes, and saved the day.

Maker Panel 2013

Here’s where I (finally) post the presentation from the 2013 Maker Resources panel, and some related links, in one place! The panel happened on Friday evening at 7PM, and I had a pretty full house for most of it. Unfortunately I once again neglected to bring my video camera to the event, but I did notice quite a few folks taking video. If you have some high quality video of the panel, I’d like to include it here.

The panel was broader in scope than just “where to buy stuff” which I did in 2012. It put more emphasis on CAD software and transferring designs to parts using digital fabrication techniques (waterjets, lasers, etc.), and in general how to design better things. I tried to include some CAD program demos of stuff like Sketchup, freeCAD, and Solidworks/Inventor, but I actually ran so far over time that the director had to step in and cut me off (Sorry Val!). Maybe next year.

Also included as part of side discussion were the slides from last year with general parts & resources.

Here’s the list of stuff I said I’d put up like two weeks ago: