This time in five weeks we'll be in the midst of the Motorama 2013 competition, yet at the moment we have zero 'bots ready to participate. Losing a week to the 'flu has definitely impacted the build schedule, so we'll just have to see how much we can get back on track. Today we're going to focus on the 'bots that are closest to being done, so we can cross some things off the list. Hit Back after viewing an image.
So here's something new to us - a BotBitz ANTSwitch. We figured out last time how it works, which sounds silly, as it's only a switch, but it wasn't as intuitive as you might think. The battery connector for the fairyweight has been cut to length, and we've soldered it to one side of the switch.
We soldered a random length of wire to the other side, and snipped holes in the polycarbonate casing of the switch for both wires. Due to the sloppy soldering the switch fits extremely snugly in the case, so no tape or bolts required.
More soldering - this time all the ground wires on the fairyweight are being soldered together: two drive ESCs, the weapon ESC, and the negative lead from the battery. Fiddly, but accomplished.
After soldering together all the positives too, we were about ready to give the 'bot it's test drive! There are a couple of minor issues to get out of the way first, such as ...
Trimming down the prop-saver bolts on the weapon motor, to ensure that they don't rub on the top plate. The already had been cut off, but as the top of the motor needs to fit in a hole in the top plate now, we wanted to trim them down entirely.
At this point we were ready for a test drive, and bolted down the lid, with all the components fitting nicely inside - yay! The 'bot was zippy, as you'd expect with Pololu HP 30:1 motors on 3S and 1.5" wheels, but the weapon wouldn't spin up. We had previously tested all the components before assembly, and everything was fine, so we're going to have to tear down the weapon assembly and see what's up.
Disappointed with the fairyweight, we decided to take a break from it, and take a look at the antweight. The issue here is that the weapon ring doesn't want to spin up. We decided to disengage one of the motors and see if that helped. It did. A lot. The ring spun up just fine on one motor, but pretty quickly slipped out of alignment.
So we needed something to keep the ring in alignment. Specifically what we needed was a 9/16" outer diameter washer. Not having any on hand, we took a 3/4" OD bronze thrust bearing and judiciously applied it to the belt sander, to whittle down the outside. Eventually we ended up with something fairly roundish, that fitted nicely.
Having formally decided to ditch the second motor - hey, instant spare! - we decided to upgrade the battery pack. You can see too that we're using a couple of bronze bushings to keep the thrust bushing in place on the standoff. With the original 470mAh battery pack, we're at 15.59 ounces, so we're pretty much good to go, finally, with this 'bot.
Happy that we finally have some progress made, we turned back to the fairyweight, and started disassembling the weapon. You can see the problem here - one of the motor leads did not 'stick' when we soldered it to the speed controller. At this point we spent a good ten to fifteen minutes trying to resolder it, but the solder simply would not 'stick' to the motor wire. Frustrated, we decided to go mechanical, and needed a simple, lightweight way to hook these wires up.
Remembering our experiences with the PWM cables from the other day, we decided to crimp a pin set to the wires, and just plug them together. The pins were a bit fiddly to deal with, as everything was still mounted in the 'bot, but it worked. We taped it up, and put the battery on the charger before testing again.
Meanwhile, back with the antweight, and we finally worked out the best arrangement of motor, idlers, and washers. The battery on top of the 'bot is just a test pack, but with this arrangement of the original two idlers at 3 o'clock and 9 o'clock, and the washers effectively taking the place of the second motor, straddling the 6 o'clock position, the ring remained engaged on the weapon motor, and all was well.
The day was surprisingly warm for a January day, and we took advantage of that to deposit some paint on the chassis of our hobbyweight Steel Stiletto. Unfortunately the photo doesn't do the paint colour justice - it's a pretty loud, neon pink - you'll have to see it in person to get the full effect :-)
One final check on Poor Punctuation and you can see we're cutting it pretty close - 451 grams (forgot to change the setting). One pound is 454 grams, so this is 15.9 ounces - fingers crossed the official NERC scale is in sync with ours.
We didn't have all the bolts in for that test, and so the two that were in unscrewed themselves, which let the weapon ring slip off the motor, hence the sparks you saw at the end, but the weapon did actually spin up, and with that, we can declare we have a working 'bot!
After looking at the field of fairyweights for Motorama 2013, they all have spinning weapons, so Lauren decided to scale down her pushy-'bot design to 150 grams, and gathered up some parts. We'll throw together some CAD designs for it, and make sure it'll make weight before committing to it.
Ta-daa! Presenting Poor Punctuation 2.5! The scrape on the top right, by the way, is from drilling the top plate (titanium) with a relatively dull drill bit to enlarge the hole for the top of the motor - the plate spun at the very end and scraped the paint a bit.
And a second Ta-daa! Presenting the rebuilt Malicious Mule. This time we think we have the right balance of speed and torque, still within a quarter-inch thick 6061 aluminium chassis. With both antweights done, we can get some skirmishing in between now and Motorama. We're wrapping up today with 20% of the fleet ready for Motorama - hurrah!
Tags: antweight, fairyweight, hobbyweight, build, pp2, tt2, mm, teti
Picking up from last night, we have some antweight issues to work out, and a fairyweight badly in need of some chassis parts. This is our last build session of 2012, so we want to make it count! Hit Back after viewing an image.
We now have all the parts and pieces for the fairyweight, so we've thrown them on the scale, and as you can see they weigh in at a nice 147 grams out of the 150 allowed. Factoring in the fact we're going to be chopping wires down, and added a couple of pieces of double-sided foam tape, we should still comfortably have a few grams to spare when all is said and done. To building!
Here we've mounted the weapon motor speed controller, and are in the process of soldering it to the weapon motor. Lots of wire trimmed off, and hopefully we can keep the fiddly soldering fairly neat.
A short while later and we have all three connections hooked up, and taped down to the baseplate, with plenty of clearance for the weapon blade above. Not a bad job, if we do say so ourselves.
Here's the result of some fairly accurate marking, punching, and drilling: #0-80 screws that have been pushed through the chassis walls. The key question is was this accurate enough to mate with the waterjet-cut top and bottom plates?
All six bolts line up virtually perfectly, and we're very happy about that. Can you figure out what we're not so happy about? An error in judgement has left the side walls with what is essentially a pivot point. The drive motors are going to be attached to these, so there's a real possibility of the drive motors splaying out as the 'bot moves. Hopefully the internals are compact enough to keep pressure on the walls, and prevent that from happening.
Here we've manually milled a small slot in the front wall for the weapon motor wires. All told this is coming together fairly nicely, which is a pleasant surprise for a 'bot this tiny.
We've mounted the battery with a small piece of padded foam tape, and tucked the balance cable back underneath itself. The receiver sits on top of the weapon ESC, and the drive ESCs sit between the two drive motors. Speaking of the drive motors, we're going to de-solder them from the ESCs and re-solder them with a fair length of wire chopped out. That means breaking out the soldering iron, which is an ideal time to procrastinate :-)
We had a pair of antweight issues yesterday - one was that the weapon on Poor Punctuation wouldn't spin up, and the other was that the batteries we had installed in Malicious Mule couldn't put out enough amps to turn the 'bot. We tried numerous different batteries in the pushy-'bot, and eventually decided that a 3S 950mAh 25C LiPo pack was sufficiently capable of giving the antweight oomph, but without being so crazily-fast that we needed the gyro, so we pulled the gyro and original packs, and installed the new pack. At 15.76 ounces we were good weight-wise, and the mix of speed and torque was about right for Lauren.
We were still stuck troubleshooting Poor Punctuation, and decided to fore-go removing the weapon motors again for today, and instead just have a skirmish between the two 'bots instead!
And a good time was had by all :-) Now, though, it's time to clean up, order up some Indian food, and throw a Mystery Science Theater 3000 on the TV, and count down to midnight, and 2013. Happy New Year to everyone!
Tags: antweight, fairyweight, build, tt2, pp2, mm
After spending the last couple of days working on the heaviest weight class for Motorama 2013, we decided to turn our attention today to the smallest 'bots. We have an antweight that needs a test run, an antweight that is seriously overweight, and a fairyweight to rebuild. Hit Back after viewing an image.
Before we start trying to figure out where to lose weight on Poor Punctuation 2.0 we decided to finish the wiring, so that the internals were done. Soldering is never our favourite task, but it's time to get to it. The wiring is a little easier in this rebuild than the previous version.
After not too long we have the positive leads all hooked up. The battery connection is aligned with a hole in the top panel, so we can attach and detach the battery with a pair of pliers as our power switch.
A bit more soldering later and the negative leads have all been similarly hooked up. With everything connected, we have all the components in the 'bot that we need, so it's time to tackle the weight issue.
As you can see, we're a full ounce overweight. With no more wire to remove, we need to start looking at structural components we can remove, without compromising the 'bot's performance.
After removing half of the nuts and bolts holding the UHMW rings to the top and bottom panels, and a couple of the internal stand-offs, we realized we were going nowhere fast in saving weight, so decided to play with some battery options to see how small the battery needed to be to get underweight. As you can see here, we wound up with a very small battery. That's a 2S 180mAh LiPo pack. It claims to be able to put out 35C continuous, which would be around 6 amps - probably not enough to run both the weapon motors, but we'll see ...
We've neatened up the wiring some with the aid of a strategically placed ziptie, so let's power it up and see what works.
Not much. With that tiny battery, the drive is fine, but the weapon motors can't overcome the friction on the UHMW ring. Because of the leads that stick out the bottom of the motors, the motor is sitting at a slight angle, which means the gear rubs the ring. So we fiddled a while trying to level out the motors. We plugged in a much larger pack to see if we could 'work in' the gears with a bit of excessive power.
While this worked to a degree, it was becoming clear we were going to have to trim some of the UHMW away from the motor/gear.
Which meant removing the motors, which in turn meant having to reinstall them after Dremeling down the ring. We've mentioned before how fiddly the #2-56 screws and nuts are. Reinstalling the motors took a good hour! We finally ended up clamping the 'bot in the vise so we cdould sit the nut in place from the front and work the screw into place from behind.
Success! Kind of - we were finally able to get both motors running, but off the much larger pack to the right of the 'bot - not the piddly little pack inside the 'bot. We let the motors run until the pack was depleted, to maximize the amount of UHMW rubbed away by the gears.
Finally we decided to button the 'bot up, and see if we could get the weapon to spin with everything assembled.
It didn't. Off came the top once more, and we sanded down the idler gears, Dremeled off a bit more UHMW around the motor gears, and that meant reinstalling the motors once again. Grr.
Finally we spent a little bit of time (relatively speaking) ensuring the weapon ring started precisely in alignment. You can see the marks we made on the ring so we would know which teeth needed to start out meshed the next time we took the 'bot apart.
Frustrated with the spinner, we switched gears and bolted up Malicious Mule for a test-run. There are two 180mAh 2S packs in there, with a custom battery adapter to put them in series. During the testing it was obvious that this battery wasn't going to be able to put out enough juice - the 'bot did fine going backwards and forwards, but wouldn't turn. We pondered our options, and decided to check out our battery stash tomorrow.
Lastly for today, we're checking out the components of our fairyweight Transcendental Terror to make sure that all the pieces from the previous version still work before installing them in the new version. Both drive motors and speed controllers were fine.
And the new weapon ESC worked just fine with the old weapon motor, so that was good. Finally something that worked as advertised today!
The remaining parts for this bot as the chassis walls, so we took out the hacksaw and some UHMW strip, and roughly cut out four pieces.
This picture didn't come out very well, but the roughly cut pieces weigh 19 grams, and we only have fifteen left, so hopefully when these are trimmed to proper size, they'll make weight.
To trim them to size, we clamped them up on Milly, and manually shaved them down to the proper dimensions - came out pretty well for a manual manouever.
When all was said and done, the parts ended up at 10 grams - so at the moment we actually have a few grams available, in theory! That'll do it for today, we're thinking. Tomorrow we need to troubleshoot the spinner ant, find a decent battery for the brick ant, and assemble the chassis for the fairy.
Tags: antweight, build, pp2, tt2, mm
We're having a bit of a cold spell here in Austin, Texas, and the temperature hasn't been getting much above 40°F the past couple of days. Looks like today is going to be a bit chilly too, but none-the-less, it's time to head out to the Build Space and see if we can't make some progress on the fleet. Hit Back after viewing an image.
Here's the current fleet status: lots of boxed parts. The beetleweight Belligerent Battler 1.0 is about the only working 'bot at this point - all the others are in some stage of [re-]construction.
We're starting today with some work on Lauren's antweight Malicious Mule, which is getting a rebuild based around Pololu 30:1 HP motors. Here we're using a (recently) trashed motor to ensure the motor mounts fit the fresh motors, with the aid of the arbor press.
And the first wheel/axle/motor/mount is successfully installed. This ought to be a fairly robust drive train when it's done, based on how solid the 'bot seems already.
Three more installs later, and all four motors are in place. Truthfully we trashed another Pololu motor installing all these, but luckily had some spares lying around.
Next is a test fit of the top plate. With three walls installed, every single bolt has gone in just fine, which is pretty impressive by Team Radicus standards.
Et voila! The chassis is assembled, and everything seems to fit quite well. One bolt missed the mark, but there are enough others to keep this 'bot buttoned up just fine.
After breaking out the soldering iron, we had some electronics installed, including the receiver, mixer, and two FingerTech speed controllers. At this point we took it for a test drive on two LiPo cells, and it was pretty zippy! It'll be interesting to see it on four - definitely going to need to get the gyro installed.
At this point we spent about two hours trying to integrate the HobbyKing gyro but to no avail - no matter how we aligned the gyro, or twiddled with the radio, the antweight would just go nuts. Getting frustrated, we put the 'bot to one side, intending to revisit it tomorrow with a fresh cup of coffee.
With that, we turned our attention to Lauren's other 'bot, Steel Stiletto which had blown up the other night, ripping up the electronics inside the 'bot, which had become displaced to outside the 'bot. You can see here one of the ESC signal cables wrapped around one of the axles. We dug it out, intending to try and repair the ESC.
Here's where we wrapped up for the night, soldering some fresh PWM cable into place to patch up the torn up part. It was getting late enough that we didn't try to run the 'bot following the repair - we'll save that fun for tomorrow!
Tags: build, antweight, hobbyweight, mm, ss
Boxing Day is traditionally the day when the upper classes would distribute food to poorer folk in the UK. Not sure that happens much any more, but for Team Radicus, Boxing Day is traditionally a build day! Hit Back after viewing an image.
We spent much of the day tinkering with our Hexy the Hexapod kit. Arcbotics released new firmware just in time for Christmas, so we updated our controller board, and also updated the control script. The kit behaved better, but it was still very squirrelly, so we decided to upgrade the power too. We switched out the AA alkaline batteries in favour of a BEC that could put out 6 volts at 5 amps. This really helped, but in complex manouvers there was still a lot of twitching, so we ditched the BEC and plugged in a 6.6V two-cell Lithium Iron Phosphate pack - suddenly things started working really well!
We taped the battery to the top of the kit, and set it on the floor of the Build Space, giving it a more stable space to wander around in, and played for a while, getting the hang of the controller interface, and also learning what the moves did in relation to the servos in the kit. Spending this time playing really helped us get the hang of how the controller is working, and helped crystallize some of the design elements we have in the back of our minds for the combat version of this kit.
After a very tasty Boxing Day roast beef dinner we decided to spend a few more hours building, opting to work on our antweight spinner. We mounted the battery pack, and started connecting up speed controllers.
With both drive speed controllers soldered to the drive motors, we moved on to the weapon speed controllers. These were just as fiddly as the drive ones, but we persevered.
Eventually the controllers were all installed, and taped down to the baseplate. That leaves wiring up the power sources and hooking up the receiver. At this point it's getting fairly late - and cold! - so we decide to call it a night.
As we're tidying up, we decide to see whether the wires we've shortened have helped much with the weight issue with this 'bot. So far we've saved a fifth of an an ounce, but we're still 0.8 ounces overweight, so we're likely going to end up removing some of those bolts in the 'bot.
Tags: build, Hex1, antweight, pp2
We recently picked up a couple of replacement speed controllers for the hobbyweight Steel Stiletto, and decided this evening to get them installed, so we could try running the 'bot with a gyro in it, to see if it would be more controllable. Hit Back after viewing an image.
The first step is to put some connectors on the ESCs, and in this 'bot we're using ring terminals, so we crimp a set on, which takes no time at all.
Having not run the 'bot in a while, we pause and hook up the batteries to chargers to let them get topped up. The batteries are well wedged into the 'bot, and we don't want to mess with taking the front and back panels off, so we elect to charge the batteries in place. We can't do a balance charge, but the odd standard charge shouldn't hurt them.
While the batteries are charging, we turn our attention to Poor Punctuation 2.0 and drill and tap a pair of new motor mounts, for #4-40 bolts this time, instead of #6-32.
Rather than try and extricate the 30:1 Pololu motors from the current mounts, we dig out a pair of 50:1 HP motors, forgoing a bit of speed, and press the motors into the new mounts.
After pressing on a pair of fresh 1" foam wheels, we install the mounted motors onto the chassis of the antweight. We also spent a little while contemplating the internal layout of the 'bot, trying to minimize the amount of witing we'll need to do, to see how much weight we can save, remembering that we were an ounce over last time.
The underside of the 'bot - that's a lot of screws! We're debating whether we can take half of them out to save some weight.
Meanwhile, the batteries in the twelve pounder have charged up, so we set about installing the new speed controllers.
Eventually everything has been re-installed, so we fiddled a bit to make sure the ESCs were plugged into the right channels on the mixer, and also installed the gyro for it's test run ...
... Which did not go well. The 'bot went into a death spin, ejecting the receiver, gyro, and a speed controller, which sparked as it came out.
Here's where the sparking happened: the PWM control cable on the ESC was sheared, so next time we get to building, we need to replace or repair the cable, and keep our fingers crossed that the gadget is still functional. So much for the gyro test ...
Tags: build, antweight, hobbyweight, ss, pp2
Shhh! Don't tell Lauren, but we're working on a Christmas present in the garage Build Space, but between waiting for wood stain to dry, we're stealing a few moments to work on the two antweights for Motorama 2013. Hit Back after viewing an image.
Having painted the titanium top and bottom plates last time, we used low-profile #4-40 bolts to attach the UHMW rings to the top and bottom. Thanks go to one of our colleagues for loaning us a T8 torx bit, as we didn't have one that small.
Next, we installed the 5/8" long aluminium spacers to the baseplate - so far so good, although we did strip one of the low-profile bolts. Here you can see the idler gears have been installed.
And on to the motors - we're reusing the motors from the last build of this antweight, although we will have to test them to make sure they work - it's been a while. Also, installing these motors is a bit fiddly!
Very fiddly, in fact, but with conviction and patience, not to mention a small pair of needle-nose pliers, we finally get both motors installed.
Here's the weapon system with both motors and both idler gears installed. The weapon ring spins freely, and doesn't shift out of alignment now that all the gears are at 90 degrees to each other.
Hmm - here's the bad news: the 'bot is currently an ounce overweight. Uh oh. We'll have to see once we've trimmed all the wiring to fit just how much we need to drill out of the titanium top and bottom plates. Hopefully not a whole lot - no pun intended!
No such worries (yet) for our other anweight - Lauren's Malicious Mule which - without two ounces of motors weighs in at 13.5 ounces, so plenty of breathing room. Seeing as though we have the 'bot out, we decided to drill and tap all the frame pieces to allow them to be assembled together, and have the top and bottom plates installed.
Things go together quite well, but not perfectly, so we may end up having to widen a few holes in the top and bottom plates, and even put the front and rear walls back on the mill for a little tweaking. But the 'bot feels solid, and as soon as the motors show up from Pololu, we'll be going full speed on wrapping this one up!
Tags: antweight, build, mm, pp2
Having spent yesterday playing with our Hexy Kit, we decided to spend some time on the rest of the fleet for Motorama 2013 today, so we picked up a bunch of parts that arrived while we were out of town earlier this week. Hit Back after viewing an image.
The first parts out of the box are top and bottom plates for our antweight Poor Punctuation 2.0. These 0.032" titanium pieces are to replace the 1/16" polycarbonate that the bolts pulled through last time out. There shouldn't be any way those bolts are pulling out this time!
From the same 0.032" titanium we had top and bottom plates cut for our smallest 'bot, Transcendental Terror 1.0. The intention is to ensure that the 'bot can run inverted this time around, which is why the top and bottom look the same.
Here are some polycarbonate parts for Lauren's antweight Malicious Mule: top and bottom plates cut from 1/8" and some motor mounts cut from 1/4".
Here are some miscellaneous parts for a comical beetleweight design, Lincoln Limboer 0.9. We probably won't take this 'bot to Motorama, but you never know ...
All our spare motor mounts - universal press-on mounts for all the Pololu motors we use on the top, and clamp-style mounts that are also good for the Pololu-type motors, but can also be used for bolting into the front of the motor.
Some heftier half-inch polycarbonate parts for our featherweight redesign, Intrusive Interloper 3.0 - enough parts to make five of the drive pods we're going to build. Guess we should think about ordering some motors, ESCs, and gears, eh?
More parts for the featherweight: top and bottom plates cut from 0.071" titanium. The top plate has a battery access panel cut out of it, to make swapping the battery significantly easier between matches - three bolts beats 46!
Some simple marking to begin with, using the calipers to etch the midline of the polycarbonate parts for the 30lb'er in preparation for drilling and tapping. At least it's unlikely we'll break a tap in plastic ...
Here we've thrown together the parts in hand for Malicious Mule, and realized that we were supposed to slot the front and rear walls for the side rails, so we load those up on Milly and let her at it.
While Milly is doing her thing, we broke out the primer and gave the 0.032" titanium parts a basecoat. Almost time to get a new can of this stuff, but it does seem to help.
While the primer's drying we turn our attention to the featherweight, and having already slotted the front and rear walls, we can put the chassis together and check the top and bottom panels. The walls will need a turn on Milly to cut a 0.071" lip for the top and bottom panels to sit in.
Here's a quick mock-up of the drive pods in the body of the 'bot. Looking forward to seeing these in action with snazzy FingerTech wheels. Hopefully they'll hold up [crosses fingers].
Here's a quick weight check for the fairyweight - it's currently running at 96 grams out of the allowed 150, with all the internals. That leaves 54 grams for the chassis, and the top and bottom plates are 19 grams each, taking us to 34 grams left for the walls and bolts. Shouldn't be a problem.
The primer's dried, so it's on to a covering of Team Radicus Purple. Still haven't figured out why it always photos as more of a blue, but no matter.
Milly's done her thing with the front and rear walls for Malicious Mule, and here's a test fit - looks good. Next to do is drill and tap the walls and motor mounts. Oh, we'd better order some motors too ...
This slightly blurry shot was taken after finally managing to install the weapon onto the base plate of Transcendental Terror 1.0 - those #2 screws and nuts are fiddly, but we got there eventually! The motor leans forward very slightly due to the wires that protrude from the underside - we were originally going to run them under the 'bot, but this will work just fine.
Here we're testing clearance on the top plate - looking good! We will Dremel down the prop-saver bolts a touch more just to be on the safe side, but really the next big thing to do for this 'bot is cut the chassis walls.
The CAD model said everything should fit, but looking at things in real life we have our doubts, but we're going to soldier on anyhow, and make it all fit, by hook or by crook.
Malicious Mule's drive train upgrade involves using proper axles - specifically ones from FingerTech designed for Lite Flite wheels. We've drilled the hubs out to 5/32" and they fit nicely. We're going to cut off that excess on the left hand side, and use a dab of glue to secure the shaft to the hub.
All four axles/hubs/wheels are ready to be attached to the drive motors next weekend. We want that part of the build to go smoothly, and have everything ready for when the motors come in ...
... So we'd better get on and drill and tap the motor mounts. Actually, as we had everything lined it, it was time to break for dinner, so we'll pick this up [hopefully] tomorrow evening - Same 'Bot Time, Same 'Bot Channel!
Tags: antweight, fairyweight, featherweight, mm, ii3, tt1, pp2, build
We had a few spare hours tonight, so we decided to hit the Build Space and do a little more on the antweight and featherweight rammers. There was some milling, drilling, and tapping to be done, but that sounded like a pretty good use of a Sunday. Hit Back after viewing an image.
First up we put the vise back on Milly and decided to edge the walls for Malicious Mule - they need to have a 1/16" lip, and it's pretty easy to get this aligned and cut for an eighth-inch top plate.
Meanwhile, we looked back at the CAD for Intrusive Interloper 3.0 and realized that we need to cut the outer rails shorter so they can be pocketed into the front and rear walls. Time to head back to the table saw.
Finaly we have some pieces for the antweight, including the front and rear rails plus the side rails, and a spare should tapping go astray ...
Having sorted out the length discrepancy with the table saw, it was time to get to pocketing, and so we added the 3/4" 6061 aluminium to the list of stuff Milly has to deal with.
After some judicious miling we had a decent boundary established for the front and end pieces, but there's work to be done on the side pieces.
Wow. That hasn't happened in some time - we've managed to break a 1/4-20" tap in some aluminium which hasn't happened in years. Time to buy a new tap, and get back to it, but in the meanwhile we have some stuff to do.
Finally we mock up the featherweight chassis to get an idea of a space it will need once completed. Everything will fit just fine, and we might be able to go to two packs in parallel.
Tags: build, featherweight, antweight, mm, ii3, mill
We have a pretty busy build schedule between now and January, intending to upgrade most of the fleet in preparation for Motorama 2013. We do have some parts, but the bulk of the waterjetted parts are still in Wisconsin, so we're working with what we have on hand. Hit Back after viewing an image.
First up, a few pounds of aluminium from Speedy Metals, specifically the chassis for a redesigned Intrusive Interloper 3.0 - three-quarter inch front, rear, and side walls, and a pair of three-eighths thick angle for the front wedge. We've slimmed down the design so the body is only two inches high.
The aluminium from Speedy Metals was cut slightly oversized, so we ran it through the table saw to trim it to length. The front and rear walls, along with the angles, are 14" long, and the side walls are 12" long, but will be recessed a quarter-inch into the front and rear walls. As we were working with the table saw we decided to chop up some 5" lengths of quarter-inch thick 6061 bar to be the chassis for Lauren's antweight, also on it's third version.
Here's the basic layout of version three of Malicious Mule, with 1.5" Lite Flite wheels, receiver, batteries, and gyro. The bar, however, is 1.25" tall, and we needed one inch so ...
... It's over to Milly to trim the stock down. While the vise is in place we'll also work on slotting the front and rear walls for the thirty-pounder too.
Ouch! Well, we've bled on the featherwight, so the 'Bot Building Gods should be appeased - hopefully the sacrifice pleases them. That'll teach us to run a hand over the underside of a freshly drilled hole - stop and check for swarf first!
Here's where we're going to wrap up for the day - the front and rear walls for the featherweight have been drilled and countersunk for the chassis bolts - we'll still need to slot them, and drill holes for mounting the wedge too, but that's another build report.
Tags: build, mill, antweight, featherweight, mm, ii3
Malicious Mule did really well in Lauren's hands at Motorama 2012, and really poorly in Toni's hands at Franklin Cup 2012. The next competition for us will be Motorama 2013, so we're going to tweak the antweight's design one more time to try and work out the issues we've had at the two events. Hit Back after viewing an image.
One thing that's been rock solid in both competitions is the choice of quarter-inch thick 6061 aluminium, which is pretty heavy duty in the one-pound antweight world, so we're going to stay with that basic chassis. No inner rails this time though.
The top and bottom plates are eighth-inch thick polycarbonate, and inside you'll see four pairs of 1/4" thick polycarbonate mounts for the drive motors.
In the ant's first competition we had old, slow-and-torquey 50:1 Copal motors - the 'bot could push most opponents, but was very lethargic speed-wise. In the second event we switched to Pololu HP 10:1 gearmotors, and while the 'bot was very quick, it barely had enough torque to move itself, let alone push an opponent. We've decided to take the middle ground, and go with Pololu HP 30:1 gearmotors, the same we use in Poor Punctuation 2.0 and Transcendental Terror 1.0, as they have a good balance of speed and push. Rather than mess with aluminium spacers for axles we're going to try out FingerTech's Lite Hubs mated to 1.5" Lite Flite wheels, the same as we used in the first version of the 'bot. The motors press-fit into the motor mounts, and ought to be fairly sturdy. Not using a bearing for the other end of the axle will hopefully mean less friction, and better performance.
The light blue box is the receiver, the two darker blue boxes are a pair of 260mAh 2S LiPo batteries that will be run in series to provide 18.8V to the drive motors. The black box in the back of the 'bot is a gyro - we still want an ant with a gyro in it! :-) The little clear box at the front of the 'bot is a BotBitz power switch.
This is what the 18.8 volts gets us - almost 14 miles per hour! That's why we want the gyro. We know from using the 30:1 motors before that they generate enough torque to push an antweight opponent, so we ought to have a good mix of speed and torque this time around.
Here's the 'bot all buttoned up. There's an access hole in the top panel to get to the battery connectors for charging, otherwise we'd have to take 28 #4-40 x 0.25" screws out every time we wanted to get to the battery. Seems par for the course in our smaller 'bots! Truthfully we may not need to bolt the motor mounts to both the top and the bottom panels, but it seems like if we have the weight it's the thing to do.
Speaking of weight, we're cutting it a bit close - there's a bit under an ounce left, and we haven't totted up all the screws yet, so there may be a touch of pocketing of the side rails being done as the 'bot comes together ...
And of course a paint job, including our attempt within Rhino3D to emulate the stickers that will be made for the 'bot. All in all it should be one solid little 'bot!
Tags: antweight, design, mm
We had high hopes for Poor Punctuation 2.0 when we took it to Motorama 2012, but those hopes were quickly dashed by a malfunctioning weapon and some nasty hits from Gyroscopic. [Unlike a certain other antweight we took - Ed.] We tried to work out how to redesign the 'bot for the Franklin Cup 2012, but couldn't figure out how to get it underweight, so we shelved it. Now the competition is done, and Motorama 2013 is a mere four months away, we decided to take another swing at it. Hit Back after viewing an image.
In the first version of this 'bot we had 1/16" polycarbonate top and bottom plates, with counter-sunk #6-32 screws. In our match with Gyroscopic we took a hit that essentially pulled the screws through the top plate, opening the 'bot up. To prevent that from happening this time we're switching the 0.0625" polycarb for 0.032" titanium. We're also switching from flat-head screws to low-profile button-head style bolts. We're re-using the UHMW rings that the weapon ring rides on.
We've also adjusted the layout and size of the spacers, going from 13 of them down to 10, and switching from #6-32 threads to #4-40, to decrease the weight of the many screws involved.
The drive is transplanted from the existing 'bot - a pair of Pololu 30:1 HP gearmotors with pressed on 1" ultralight foam wheels, and polycarbonate motor mounts.
The other issue was the weapon ring not spinning up. Here we've made sure to align the weapon motors and idlers at 90 degrees from each other, to ensure the ring is centered.
One thing we're not sure about is the battery - it was a 3S 470mAh pack, but due to weight we may need to drop down to a 370mAh pack. The red weapon ESCs are the same, and so is the 4-channel Spektrum receiver.
Here are all the internals in place. The only thing you're not seeing are the TinyESCs that power the drive motors, but experience tells us it's going to be pretty easy to cram them in between the drive motors and battery.
Here we've buttoned the 'bot up. Yes, it will take fourteen screws to access the inside, but we're leaving a hole to access the battery connector and will use in-'bot charging unless we're pressed for time and need to simply swap in a second battery.
Here's the bit we're worried about: weight. We did figure out why we were having such a tough time getting close on weight before - we had the density of the weapon ring and gears set to steel, not titanium, which doubled their weight.
The estimate there doesn't include the copious number of quarter-inch long #4-40 screws that hold the 'bot together, so we're going to have to keep our fingers crossed that we've over-estimated, and that we can trim enough wire, etc., to keep the weight to a pound. Failing that we'll be drilling the heck out of the UHMW rings, and potentially the top and bottom panels, in addition to switching the battery.
One final render with (bright) team colours - we obviously picked the wrong purple in Rhino this time, and the sheer quantity of steel bolts really does stand out ... Next step is ordering the titanium and having it cut - watch this space for updates!
Tags: antweight, design, pp2
This is our last build day before NERC's Franklin Cup 2012, and we have three working 'bots, one that needs tweaking, and one that still has a fair amount to be done. Time to get cracking! Hit Back after viewing an image.
We have a bunch of wiring to do on Nihilistic Naysayer 2.0, and the best place to start is probably with the batteries. This shot reminds us that we actually need to make a rear wall for this 'bot too - better add that to the list.
The new rear top plate unfortunatly doesn't match, as we couldn't find the brand of paint we usually use, and the new can is a bit bluer than the original, but at least it fits.
A quick test weigh-in, and things are looking good - 11lb 10.6oz, and that's without cutting down the rear wall yet, so no worries on weight. We're probably going to have to trim a bunch of wire out of the 'bot too, because it's pretty packed in there.
Speaking of cutting the rear wall, we had a little trepidation with this, as there's only 1.5" between the blade and the fence, and the part is curved, so this seems dicey.
We took a breath and went for it, but this is as brave as we were feeling - we made it about half-way on each side before bottling out, as our fingers were a tad too close to the blade for comfort.
After debating a bit how to finish this part, we decided to wrap up the cutting with the jigsaw, which was much safer!
We left the wall to cool down and went back to wiring. We can feed the battery wires into the front compartment to hook up to the power switch. We can also bring one set of drive motor wires in there, to meet the ESC, but the other motor doesn't quite stretch that far.
Here we've put the drive ESCs and power switch into the front compartment, along with the weapon ESC. It's really crowded in there, and so we're going to need to trim wires some to be able to get the lid on.
Back to the rear wall, and we cleaned up the jigsaw cuts with the belt sander. Again, we had to pause to let the wall cool down, but it came out pretty clean, so we're happy with it.
While the wall cools we turned our attention to the littlest 'bot, Malicious Mule, and fitted the fourth wheel which arrived yesterday. After bolting on the side rails, we took the 'bot for a spin - almost - the friction of the rubber wheels on the side rails meant it hardly moved at all. Uh oh.
After a quick weigh-in (15.0oz) we decided two things: (1) to replace the 2S battery with a 3S one that is only 0.3oz heavier; and (2) to cut new front and rear walls to allow an extra eighth of an inch of space between the wheels and outer walls to eliminate the friction.
Back to the hobbyweight, and we've removed the on/off switch and replaced them with simple jumpers to force the ESCs on. We're going to hot-glue the PWM connectors and power jumpers so they don't come off in combat.
Here we are fitting the rear wall. We're simply going to drill and tap for four bolts, rather than the elaborate curved slot it was supposed to sit in, in order to save time and complexity.
After drilling and counter-sinking the rear wall we were able to finally put some primer on it. This is the last piece of the 'bot - all that's really left is wiring, finally.
We start that by putting our favourite PowerPoles on the batteries. We're pretty sure we can install these in our sleep at this point!
It's a little tough to see what's going on here, but we've hot-glued a pair of LEDs to the middle wall as power light indicators. Much more compact than the dual-blue ones we've used in other 'bots.
To match the new power lights we've drilled view holes in the top panel, and also a new hole for access to the power switch.
Our thoughts habe turned to packing, and although this wasn't a consideration during the design phase, Intrusive Interloper 2.0 fits perfectly in the Pelican case. Unfortunately the 'bot and the case weigh 47lb together, so this is definitely going to be an overweight bag! Oh well.
Here we've fitted the rear wall. It isn't exatly per the original design, but it fits just fine, and we're glad it's done.
Here we've installed the new front and rear walls and the 3S battery into Malicious Mule and taken it for another test drive. The 'bot moves, and is pretty zippy, but is definitely missing the torque it used to have with the old 50:1 Copals. We're thinking the 10:1 reduction on the Pololu motors might be a little too low, so we're contemplating switching the drive motors to 30:1 ones.
Here we're in the midst of wiring the drum-bot, and we're trying to be judicious in how we trim the wires, but truthfully it's getting late and we're losing focus, with packing on our mind too, so we're not entirely convinced this 'bot is going to be complete when it's packed up.
Ouch. Toni walked into an aluminium bar. You're not seeing blood trails here - this gash does in fact run that far down her leg. Well, at least it woke her up a bit!
More wiring, and it's definitely time to call it quits for the night. Tomorrow morning we'll just have time to pack and then run for the airport. Looks like we've fallen back into our bad habit of building in the hotel room - the wiring for this 'bot will have to be completed in Philadelphia. Nursing a cut leg and bleary-eyed, we wrapped up for the night and headed to bed.
Tags: antweight, build, mm, nn2, hobbyweight
Okay - we need to "Make it work!" as Tim Gunn would say. On the agenda for today, we want to get Intrusive Interloper 2.0 running reliably; get Steel Stiletto running reliably; try to finish Malicious Mule; and try to finish Belligerent Battler 0.9. Sounds like a lot to do, so we'd better get started! Hit Back after viewing an image.
Having picked up some Y-cables from the local hobby store we set about re-wiring Intrusive Interloper 2.0 with four Victor 883 speed controllers, one per DeWalt. The wiring was a [messy] piece of cake, but it turns out two of the Victors were bad. Here we're swapping in spares.
Argh! Of our two spare Victors, one of those was also bad, so now we're in a bind. We have three of the four motors hooked up, and one lame duck.
Ouch - $600 of blown electronics sitting right there. We were stumped. We scoured all our parts bins, and even tried wiring in one of the hacked TZ85As, but that didn't work either. We weren't convinced we could get a speed controller in time even if we ordered one. This was not a pleasant feeling.
Suddenly inspiration struck - and we pulled out the pile o' parts for the Sportsman we began building for Motorama 2012, and struck gold! There was a Victor 883 mounted to the baseplate! Fingers crossed it works ...
And it did! Hurrah! We now have Intrusive Interloper 2.0 running like a champ. Shame we never got the gyro to work properly, but no matter, we actually feel like we have a 'bot that's working properly. Even if we accomplish nothing else between now and next weekend we have a featherweight and a hobbyweight - more than enough reason to fly to Philly :-)
Steel Stiletto is working fairly well on the new battery pack, but certainly has some control issues, predominantly due to the kludged-together drive train. With a bit more time we'd re-make the hubs for the wheels, but for now we're going to just try 'breaking them in' and see if we can get the 'bot to be a little more controllable. Again, another instance where having a working gyro would be useful, but oh well.
Moving on, we go from the largest 'bot to the smallest: Malicious Mule. Here we've pressed bushings into the outer rails, and we're about to fix the wheels to the axles.
A quick weight check shows that there's no worries in terms of weight - the scale reads 14.6 ounces, so we don't have to sweat that aspect of the 'bot - we just need to finish assembling it.
Here we've bored the wheel hubs out to a quarter inch and pressed in aluminium spacers which will be our axles. The hubs will be pinned to the spacers, and the spacers have been drilled and tapped for a screw to hold them to the Pololu motor shafts.
Here we have the first two axle/hub combos installed. We currently only have three of the four wheels we need for the 'bot, and we're waiting on the Robot Marketplace to make good on the last one. Hopefully the wheel will show up before we get on a plane on Friday ...
All in all we're in pretty good shape with this antweight. All we need to do is tame the wiring and put the fourth wheel on. We did take it for a quick test drive, and the speed is markedly improved over the previous version!
That's practically three 'bots running, so let's go for a fourth. Here's our To Do list for the beetleweight Beligerent Battler 0.9, and although it seems like a fair bit, there's not really that much to do, so we hop to it!
Here's a pair of top and bottom plates quickly cut out on the table saw. We're going to use the jigsaw to cut the wheel holes, give them a lick of paint, and then we can install them.
We've also trimmed down the front wall to allow the timing belts to pass from the weapon motors to the beater. We basically cut 3/8" off each end and installed spacers. We've also installed the weapon motor mounts.
As it's getting late we want to get all the noisy work out of the way quickly, lest we incur the wrath of the HOA, so we quickly cut and sand the wheel holes in the top and bottom plates.
We ground a flat on the weapon motor shafts, and installed the timing pulleys with screws and a dab of Loctite. Hopefully they'll spin - we're not worried about them coming off, because there's nowhere for them to go in the 'bot, it's more making sure they stay engaged on the motors.
And here they are installed! We're contemplating milling a shallow pocket in the side walls, as the pulleys do rub a tiny bit, but we'll see how it goes when we hook everything up and give the weapon a test run.
Here we've installed the baseplate, and right now we'd have to say things are looking pretty good! We're not going to get this 'bot finished tonight, but hopefully tomorrow evening we can do the wiring, and barring any major issues, ought to be able to wrap up the three-pounder tomorrow.
So then the decision will be what do we do next? Both the antweight Persistent Pugilist 0.9 and hobbyweight Nihilistic Naysayer 2.0 have a bunch of work to be done to get them ready. We're thinking we forego the antweight and concentrate on the 12lb'er, because that weight class at Franklin only has five entrants, which could help our chances of winning something, versus the dozen or so antweight entries. Sounds like a plan!
Tags: build, bb1, beetleweight, antweight, mm, featherweight, ii2
We got a late start today, having to spend the morning and first part of the afternoon sorting out a client, but we quickly got into the swing of it, desperately wanting to get at least one "Presenting" post out today, as we're short four working 'bots with exactly one week to go. Hit Back after viewing an image.
After running the 'bot with the second new 9.9V A123 battery pack we're happy with the current state of the rebuilt Steel Stiletto, so we're going to call this 'bot done! Presenting the rebuilt Steel Stiletto!
Moving on, we're done with the re-wire of our 30-pounder Intrusive Interloper 2.0, having wired in four Victor 883s but we're short a couple of Y-cables for the drive ESCs, so we can't test-drive this configuration just yet - we've made a note to hit our local hobby shop tomorrow so we can scratch this 'bot off the list.
It's not stretching the truth to say we had some "issues" tapping the 1/4" 6061 aluminium rails for Malicious Mule, so here's a fresh set from Team Whyachi which have been drilled and tapped without incident, ready for a fresh coat of paint and installation.
Here we've begun assembly for Malicious Mule, with the 10:1 HP Pololu drive motors mounted to the inner rails, and the base plate attached so we can start looking at the internal components.
Here's a test layout for the battery pack, receiver, and gyro, for the 'bot Malicious Mule. Two things strike us imediately after taking this photo:
1) There's not as much space inside this 'bot as our CAD suggested; and
2)We've had zero luck thus far in the build season for gyros, so we're not expecting this to go well.
It's very rare that we feel good about soldering something, but we think we did a pretty good job putting leads on the 10:1 HP Pololu motors, and so the next task is to connect the ESCs.
To reiterate: our soldering skils are not that good. It took over an hour to go from the previous photo of leads on motors to this pic of motors connected to speed controllers, but eventually we got there.
The final challenge of the night we wanted to take on, was getting the receiver to bind with the radio. We plugged things in, unpluged them, plugged half of them in, and eventually got the receiver to bind. Next was calibratintg the ESCs, which also took a while, including swaping the V-tail mixer. But finally we had it done. Tomorrow all we have to do is sort out the drive axles, and we have another "Presenting"' post on our hands, assuming we don't try to use the gyro ...
Tags: build, hobbyweight, ss, featherweight, ii2, antweight, mm
This time in two weeks we'll be competing in the Franklin Cup in Philadelphia, and at the moment the main thing standing between us and victory is ... well ... not having finished 'bots! Hit Back after viewing an image.
As you can tell from our To Do lists for each 'bot, there's plenty yet to do! We're hoping to have quite a few items checked off by the end of the weekend. There's a simple pleasure in scratching out things on a To Do list.
And here are the materials we'll be working with this weekend - five boxes full of parts, waiting to be milled, drilled, and assembled into mighty warriors. Or at least worthy competitors!
For whatever reason the new paint for Malicious Mule and Steel Stiletto never fully dried. While milling these parts for the antweight the paint bonded, so these pieces need touching up, but at least they're done with tapping.
We're trying to get all the milling done that needs the vise, before we take it off for all the flat milling. Here are the side rails for the hobbyweight Nihilistic Naysayer 2.0 getting niches milled for the top and bottom plates.
Hmm. With Milly's head lowered as far as it will go, the end mill still doesn't reach down to the part. Time to break out some risers so we can slot some parts.
With two chunks of 3/4" UHMW under the wall, we can begin to slot them. This is the front wall for Steel Stiletto being slotted for the inner rails.
While Milly is doing her thing, we put some connectors on the 2S 2Ah lithium iron phosphate batteries that will be linked in series for Steel Stiletto. We ended up buying three two-cell packs simply because Hobby King was out of three-cell packs, but the smaller size gives us a little more flexibility in where they live in the 'bot.
Here's the inner chassis for Steel Stiletto - everything lines up nicely - ignore the fact that the left rail seems bowed - once assembled everything actually sat in place nicely.
Yet more slotting - Milly's having a busy day today! Here we're slotting the side rail for Nihilistic Naysayer 2.0 for the front and center walls ...
... Which came out quite well, except we forgot to do a final pass on the middle wall, so it's only 1/8" deep instead of 1/4", so we'll have to fix that tomorrow!
All in all a very productive day again, so let's hope we keep that momentum going through tomorrow, and maybe we'll be able to finish up a 'bot tomorrow! Stay tuned ...
Tags: build, hobbyweight, antweight, mill
Hot on the heels of yesterday's efforts, we spent another long day in the Build Space, shooting to get as much fabrication done as possible for our six-'bot fleet for NERC's Franklin Cup. We made good progress yesterday, and was hoping to keep the momentum going today. Hit Back after viewing an image.
Lauren's getting in on the action, putting a revised colour scheme on her 'bots.
Steel Stiletto and Malicious Mule will be returning with more power, more driveability, and more armour. They did a good job breaking oponents weapons at NERC 2012 but you ain't seen nothin' yet! Note the hot pink colour scheme after comments by onlookers that pure pink looked like Mary Kay (barf).
First up for Toni this morning, some drilling and tapping. It doesn't take much time to have the front and rear walls reasy for a test fit for the antweight Persistent Pugilist 0.9.
And the another run, albeit with a slightly larger tap, to be able to put the chassis for beetleweight Belligerent Battler 0.9 together for a test fit. Both 'bots have some slotting needing doing on Milly, but one thing at a time.
Speaking of Milly, we ran and endmill down the UHMW tube that will be the antweight's drum, and were able to put two pieces of 1/4" keystock in the channels without a lot of effort, so that works.
On the other hand, after drilling and tapping the keystock for the #6-32 botls that will pass through the drum and attach the two teeth to each other, this was a pain in the behind! Despite the effort, it came together well, and we're pretty pleased with how the drum is shaping up!
We next turned our attention to our thirty-pounder and, having finished the wiring harness, decided to power it up, and figure out the R/C wiring. After a minute or so of running, the drive motors were faltering, and things did not sound right. The photo didn't capture it, but this drive motor was smoking slightly, and you'll see in the photo that the two LiFePO4 battery packs are in series - they weren't when we first started working, so there's a pretty good chance that in addition to replacing the back two motors - neither of which were working - we're going to have to ditch these battery packs too - darn!
After some time and effort the two rear motors were switched out, and we fired up the 'bot again. This time three of the four motors sounded fine, with the fourth not spinning at low speeds. As all four were showing some signs of life, we decided to figure out what was connected where. We're not doing transmitter-side mixing, as we have a gyro in the 'bot, and it took a little time to determine which receiver port was steering, which was throttle, and which channels to reverse on the transmitter, but eventually we had everything plugged in properly.
We also decided to play a bit with the gyro. Here it is plugged in, and of course it pretty much went nuts, as we would send the 'bot a turn command, and it wouldn't turn as it had no wheels, so the gyro sent the motors into overdrive. On the plus side, we know which way to flip the third channel switch on the transmitter to disable it :-)
Time for a weight check, and something's not quite right here. We've switched from 1/4"-20 bolts for the front wedge to #10-24, yet the scale is suddenly showing a full 30lb! Eek! We decide to ignore it for now, and soldier on, hoping it was an abberation.
Here we've trimmed the drive axles to length with the Dremel-ish, and cleaned the ends up with the belt sander, so we're pleased to see them fit right in to the bearing we had so much trouble with in the past.
Here we're figuring out where the wheels need to be pinned to the shafts. We've put 1/2" bushings between the wheels and the inner rails, and that seems to leave them in the right spot, so we can go from here to actually pinning them.
We've kept it simple, and put a 1.5" long 1/8" roll pin through the shaft into the wheel. Fingers crossed the wheels survive at least a couple of matches, because these pins are going to be bears to get out if we need to replace them, but these wheels don't have a lot of surface area to play with.
Here's a quick shot following the first test run! The 'bot went bezerk, running into a shelving unit in the 'build space, but we suspect that was something gyro-related. Otherwise the 'bot is pretty zippy, and we need to seriously dial down the turning so it's not so extreme.
To wrap up for the night, we decided to check the scale one more time. As you can see, the scale is saying 31lb 5.4oz, which doesn't make any sense, as we've cut parts, not added them, and it was underweight the last time we played with the 'bot.
Frankly, we're suspecting the scale, so we break out the 150lb-capacity Pelouze, and sanity is restored: 28.4lb. It doesn't have the resolution the 40lb scale has, but we trust it. When all is said and done, we can always to hit the mailroom scale at work, and see which one is right.
Wrapping up for the night, we reflect it's been a very productive weekend. Hopefully we'll have our first "Presenting ..."" post for a Franklin-bound 'bot, and we're planning on making at least as much progress again during the week, leading up to another major build weekend next weekend!
Tags: build, antweight, beetleweight, featherweight, ii2, ss, mm, bb1, pepu1
Argh! Three weekends left before NERC's Franklin Cup and we have zero finished 'bots! Seeing as though we had a large delivery from Wisconsin and also Australia yesterday, today was shaping up to be a big build day. Hit Back after viewing an image.
We spent some time cutting polycarbonate and 6061 aluminium on the table saw right out of the gate today. Unfortunately we had some aluminium that was too small to be safely cut on the table saw so we had to go old-school and break out the hacksaw. Here we've cut some walls for the stand-in drummer antweight from 1/2" x 1/8" aluminium.
Here's another set of parts we hacksawed from 1/2" x 1/2" 6061 aluminium stock - custom 'Nut Strip' for Lauren's revised version of her hobbyweight Steel Stiletto. After cutting them and drilling them we decided to test the fit using some 13/64" drill bits.
Also for Steel Stiletto we have some 1/4" polycarbonate internal rails which need to be end-drilled and tapped for #6-32 bolts. Fortunately this goes without issue, and things are progressing well.
More end-drilling - this time for Lauren's antweight Malicious Mule with some 1/4" 6061 and polycarbonate too, all being end-drilled for #4-40 bolts.
Here are the inner rails for Malicious Mule after drilling and awaiting tapping. We've had a pretty accurate drilling day in the Build Space, and we're pretty happy about it!
Yet more end-drilling and tapping - this time for Persistent Pugilist 0.9 - our stand-in antweight - as we work on the front and rear walls, that were hand-hacksawed then trimmed to length on Milly.
We also threw some effort into our replacement beetleweight, Belligerent Battler 0.9. Aside from cutting walls we also drilled and pinned 1/16" roll-pins through the timing belt pulleys and shaft in anticipation of hooking this beater up to the weapon motors.
A quick test layout of the beetle, realizing that the UHMW walls need to be slotted for the front and rear walls. Things seem to be fitting okay, so that's a relief!
A final shot for the day of the new chassis for Steel Stiletto - 1/4" titanium side rails and 3/8" 6061 for the front and back. The custom 'Nut Strip' pieces fit well, and the chassis is solid!
Hopefully tomorrow's build report will give a better sense of the amount of grunt work that was done today - we kicked butt as far as fabrication went - so it's time for a rest, in anticipation of maximising our time tomorrow!
Tags: build, antweight, beetleweight, hobbyweight, ss, mm, pepu1, bb1
In trying to redesign Poor Punctuation 2.0 to make it sturdier we were having terrible weight issues, so we wiped the slate clean, and doodled for a while. After a short while, we'd come up with this antweight design, and we've decided to build it for Franklin. Hit Back after viewing an image.
The chasiss is a blend of 6061 aluminium (front and rear walls) and polycarbonate drive walls and top/bottom. We went with aluminium in order to try and put some rigidity into the chassis.
The outer rails are 1/4" UHMW, slotted for the aluminium walls, again to try and increase the stability of the frame.
This is a two-wheeled drive train, with Pololu HP 30:1 motors, TinyESCs, and 1" foam wheels, just like we used in Poor Punctuation 2.0.
And here's the business end of the 'bot - a 5" length of 1.5" diameter UHMW tube, with 1/4" steel teeth milled into it. We will use #6 bolts going through one tooth and threaded/Loctited into the other tooth to keep both teeth in place.
What's going to make this interesting is that powering the drum are two of the 2204-14T motors we used in Poor Punctuation 2.0, bolted to the side walls, and then the set-screws that act as the retainer for the prop saver will be removed, and those holes will be bolted into from the outside to secure the pipe to the motors.
In order to provide the juice to the pair of weapon motors we need a freakishly large battery - the blue brick is a 1000mAh 2S 25C LiPo pack running to the two TinyESCs and two reversible weapon ESCs. The orange box is the receiver, and there's even a little bit of space left inside!
When Persistent Pugilist 0.9 comes out swinging at NERC's Franklin Cup, needless to say it'll be in team colours, and fingers crossed survives the first hit ...
Tags: antweight, design, pepu1
Lauren did really well with her first ever 'bot at her first ever competition, going 3-2 with Malicious Mule [But we're not bitter - Ed.] The one flaw was a lack of speed, as those 50:1 Copals, while having plenty of pushing power were geared very low - we only used them because we had them handy. As an upgrade, we're putting very fast motors into this redesigned antweight, and tweaking a few things around them. Hit Back after viewing an image.
The chassis of the first version was made from 1/4"-thick 6061 aluminium, and came away from the competition with barely a scratch on it, so there's no particular reason to change that part of the design.
A small change for version two will be the use of polycarbonate for the inner walls, rather than more 6061, to save a little weight. We're also going to switch from a UHMW top and bottom to polycarbonate, and it will be fitted, rather than just 'sitting' on top.
The drive motors will be Pololu HP 10:1 gearmotors, with 1/4" aluminium axles mating with 1.25" diameter rubber wheels, rather than the foam ones we had previously. Depending on time, weight, and inclination, we may try making wheels with the 40A durometer urethane we're playing with.
Not an intuitive render, but here's a quick run-down of the electronics in the 'bot: the white block is a BotBitz power switch, the dark blue box is the 300mAh battery, the light blue box is the receiver, the red box is a V-tail mixer, and the coup de grace is the pink box - a gyro! Yup, this ant is going to be a fast sucker, and we're going to do everything we can to make it as driveable as possible.
As you can see from the Tentacle Torque calculator, these motors at just 7.4V (2S) are going to get the top speed up to over 13 miles per hour! Hence the gyro ... although truthfully, how fast it'll top out in an eight-foot arena remains to be seen, but still - pretty zippy!
Weight-wise we're doing well - 92% of our one pound allotment has been used up, with just bolts to account for, so we're fine here.
We're not sure whether we'll be taking this 'bot to the Franklin Cup or Motorama first, but it should be a quick build, so plenty of time to practice driving it.
And of course plenty of time to paint it :-)
Tags: mm, antweight, design
This site contains records of our trials and tribulations in building combat robots. So much to learn, and so little time!