After running some errands this morning - including picking up some metric hardware - we're ready to get to it, and see if we can't finish up the drumbot build. We need to install the new drive motors/wheels and finish up the wiring. Once this 'bot is done, all we'll have left is the walker. Let's see if we can get ourselves down to just one 'bot left ... Hit Back after viewing an image.
Using the M4 screws we picked up from Home Despot this morning the drive motors mount okay - we were out of alignment in drilling one hole, but we'll blame that on it being metric :-) Now we can assemble and move on to wiring.
The side rails are back on, and so is the curved rear wall. We're finally settled on the placement of the electronics, so we can move on to hooking everything up.
There's just enough room for the power switch, which has been mounted in the rear compartment. We've tied all the ground wires together, and hooked the battery and weapon speed controller to the switch, along with a jumper wire for the two drive ESCs, so things don't get too crowded around the switch.
We've spent so much time in the build space recently that we're now on to the third season of Stargate SG-1! We'll likely finish this boxed set too before we hit the road for Harrisburg.
The first motor has been wired to the speed controller, after spending a little time with jump leads to determine the spin direction, and make sure left is left and right is right. Note that the motor actually isn't spinning in this shot - it's from where the motor rubbed a wire when it was in the featherweight, but it looks like it's constantly in motion now.
And on to the second motor, again with the jump leads to ensure we have the proper spin direction. This doesn't take too long, and we're able to trim the ESC leads to length and make the final connections.
Et voila!We do need to hook up the weapon ESC to the receiver, and drill a hole in the new rear top plate so we can get at the power switch. While we're at it we may throw a lick of paint on the new panel too.
Here's the 'bot all buttoned up, sans paint and power hole. There's one other thing missing too, at this point ...
A quick weight check shows us at 11.8lb out of the twelve allowed with everything accounted for but one thing: what we're going to stick to the motors for traction. We're debating the use of the grip tape, based on what it did to the Build Space floor with the previous motors. We're wondering whether we should switch to a layer of adhesive-backed neoprene for traction instead, and so we've put some on order from McMaster. Unfortunately it won't arrive until Wednesday, after Toni leaves in the BotMobile, but Lauren's flying in to Motorama, so she'll throw it in her suitcase before heading to the airport. We're not going to be able to call this a "Presenting" post, as the 'bot isn't 100% done, but it's sure close!
Tomorrow the balance of our metal gear servos show up, so we'll be assembling the combat Hexy kit, and that leaves Tuesday to fabricate the weapon for the walker and pack!
Tags: build, nn2, hobbyweight
After wrapping up our featherweight yesterday we're left with the 12lb drumbot and 3lb walker to work on. As the hobbyweight is closer to completion than the walker we'll start there today. We need to wire up the drive train and take it for a test drive! Hit Back after viewing an image.
We've cranked up the Keurig, and in a caffiene-induced frenzy set about configuring the wiring inside the hobbyweight. Here we're working on finding the right collection of settings so the wheels run in the direction we indicate with the transmitter. After reversing channels, motor connections, and also receiver connections we finally have the right combination - to the test drive!
Hm. That didn't go exactly as planned. You can see the scuff marks on the Build Space floor that the 'bot has left while it was spinning donuts. The original motor is plenty powerful, and is able to move the 'bot. The new motor isn't powerful enough to do the same, and by the end of the test run all we'd managed to make it do is smoke. Note also that the grip tape is not as ideal a tyre coating as we imagined - there are many spots where it simply ground up the concrete floor. It looks like we're going to have to stop and re-think this drive train ...
Before we know what we can do, we need to know where we're starting from. At the moment the 'bot weighs about 10.8 pounds out of a maximum of twelve, give or take a lid and some small screws. That gives us a pound-ish to engineer a solution.
We've disassembled the whole 'bot, near enough, while we scour the Build Space looking for drive train components that might work. Either we need to gear the brushless motors, like we did in the recently completed featherweight, but finding appropriate transmission components is not going well; or we could switch to a brushed setup, but the issue there is space - fitting a brished motor and gearbox is going to mean making a wider chassis, which isn't really an option given the time available.
Option number three: moar power! :-)
This is the 'bot with the two existing drive motors removed and the two G60 weapon motors from our retired featherweight Formidable Fustigator 2.0 switched in. As you can see we're up to 11 pounds, without a revised chassis back end to accomodate the significantly longer motors.
Time for some P.A.D. - paper-aided design. The inside of the 'bot is 9.25" across. The new motors are 2.3125" long, so that leaves 4.625" of space for the chassis components. Subtract two times a quarter inch for the walls, and we have a space 4.125" by 3.5" to work with. We drew a 1:1 scale box, and here we're test fitting the speed controllers and power switch inside that space.
Confident we can make it work, we've cut new top and bottom plates from quarter-inch thick polycarb, and marked, drilled, and countersunk them.
Here's the new rear chassis bolted to the middle wall. The next step is actually fitting the speed controllers, power switch, and all the wire in this small space.
We did sand down the top and bottom plates to match the curve of the rear wall, and it came out nicely. When we're done we may actually be able to drill and tap the aluminium side walls to bolt them to the rear wall for some added stability.
Ugh - already this is looking pretty messy. With the battery and weapon speed controller in the front compartment we need to fit two drive speed controllers and the power switch in the rear component, and then decide the best location for the receiver. Argh - so much wire!
But the good news is that barring a few screws, this configuration will easily make weight, so we're going to press on and see whether we can make it happen!
This blurry shot is where we removed the bronze bushing that was in there for the old motors, as the new ones have larger dimensions so we need to accomodate those.
Here's a test-fit of one of the new motors. One thing we didn't consider is that now the aluminium side walls aren't recessed into the middle wall, so the hole that was there for the old motors is now about a quarter of an inch in the wrong place.
Having marked roughly where there needs to be a clearance hole in the side rails, we handed them over to Milly to cut out those holes.
Much better! The motor fits okay at this point.
Because we've hogged out so much of the inner walls, we need to mount these motors to the outside walls this time around. After using our CAD file to determine the placement of the holes for the 30mm metric bolt pattern we drilled and countersunk a set of mounting holes. They came out pretty accurately as best we can eyeball by holding one of the motors up to them.
Time for assembly! And we came to a screetching halt: the motors use 3.5mm pitch metric screws, and we none. Plus, we're out of ring terminals if you can believe it! Gah ... well, we figured out a shopping list for tomorrow morning, and turned our attention to the last remaining 'bot ...
... The beetleweight walker. All the leg parts are now dry, so we can try assembling one. We have enough parts to make seven legs, plus a spare set of foot parts, as we imagine those will be the ones taking the most dings as our opponents crash into us. Here we've pressed together a thigh, using the arbor press to ensure things are snug. Note to selves: next time we have slot and tab parts cut, underside the tabs a bit. Still, with the arbor press, and given that this stuff is 6061 aluminium, we can make it work.
Here we're in the midst of attaching a foot. The foot servo is connected to the controller board to ensure it stays stationary while the foot is being attached. Our only niggling doubt about this design is that we're using the plastic servo horns that came with the servos for this build - hope that doesn't prove to be a major weak point later on down the road ...
Oops. Further note to selves: pre-drill holes before installing components - do not attempt to drill hole with part in place. We've accidentally drilled through a servo. Well, we have a spare, so we can carry on for tonight, but we need to make a decision: do we pull all the metal gear servos from the plastic kit for this build, or do we wait for our second shipment to show up? USPS shows it cleared customs in Illinois today, so there's a good chance it'll show up Monday, or worst case Tuesday. We have the day to build and pack Tuesday, but will a day be enough? On the other hand, keeping the plastic kit intact will allow us to work on sizing the weapon properly and ensuring our wireless control scheme works. While we try to make an executive decision we continue with the leg assembly.
Here we have the foot installed, and it moves surprisingly cleanly for being heavier than the plastic one, and a much tighter [press-]fit together. Additional note to selves: press all the captive nuts in before continuing with build.
After not too much longer we have a finished leg! All the servos turn freely, so that's a plus, and we haven;t damaged any more during the completion of the leg, which weighs in at 5.86 ounces. Therefore six of them will weigh a grand total of two pounds and 3.16 ounces, give or take. This is one hefty beast - beetleweight-wise anyway!
We still haven't reached a decision on whether to disassemble the plastic kit - we're going to sleep on it and see how much time we have tomorrow after we finish the drumbot and fabricate the weapon for the walker. It may be that we wait until Monday anyhow, and if they don't show up Monday, use the day to test the wireless control on the plastic kit, then salvage the metal gear servos from the plastic kit and continue assembly of the combat Hexy Monday night and Tuesday, then reassemble the plastic kit in the evenings while on the road to Harrisburg, PA, later next week. That sounds like the plan - at least for tonight :-)
Tags: build, beetleweight, hobbyweight, nn2, Hex1
Almost a third of the intended Motorama 2013 fleet is yet to be completed, and we jump in the BotMobile in five days! Fortunately it's not as grim as it sounds - both the featherweight and hobbyweight aren't actually that far from completion, and the beetle walker is essentially a kit, so fingers crossed that one goes according to plan. Today we'll focus on the featherweight Intrusive Interloper 3.0. Hit Back after viewing an image.
First: to the paint shack!Having picked up a fresh can of matte black, the leg parts fo the beetleweight walker get a healthy dose of spray paint, and are left to dry while we turn our attention to the other end of the weight class spectrum.
We have one drive pod that refuses to run in reverse, so our first task for today is to replace it with the spare. We cut some axle shaft, asembled the gear, wheel, and core, and were ready to wire the pod to match the one being removed.
Here we're in the midst of replacing the defective pod, and it's not as plug'n'play as we were originally intending. Given that this 'bot is about six pounds underweight, the next iteration will have both weight and space for better modularity. Maybe we can come up with a way to use PowerPoles to click a drive pod in for power, rather than have to mess with these ring terminal stacks.
But success!Note the motion blur on the wheels and motors - this pic was taken with the transmitter stick at full throttle; which makes quite a racket too! We didn't notice initially, but the back left wheel is actually rubbing on the cardboard box edge that the 'bot is sitting on - oops!
To help clean up, we pulled out the Dyson mini-vac and got all the shavings out. We also had a drive pod that siezed up at this point - the front right one - turned out the set screw in the collar on the brishless motor had undone itself sufficiently to get embedded in the polycarbonate - oops! Another modification we're going to work into the next iteration is a thin polycarbonate wall seperating the wheel from the gears - this will help keep debris and detritus from the floor getting into the gears.
But all in all it was a success - we could actually run straight, and turn on command. Trushfully, we're not sure how quickly we're going to wear through the 45A durometer wheels, but we have plenty of them, and driving with the left/right on the left stick is weird, but that's what driving practice is for.
With some time left yet this evening we turn our attention to the hobbyweight. This one, too, has a brushless drive train, but the idea was that the motors themselves would be the wheels. One of the motors was damaged at Franklin and we never got around to ordering a spare. Instead we mounted one of the slightly smaller ones we ordered erroneously to go in the wheels. Here we're in the midst of laying out the electronics.
The trick is trying to cram this stuff in in such a way that it makes sense and is easy to maintain. With the smaller LiPo battery versus the LiFePO4 ones we used at Franklin we have more options, but the optimal configuration is eluding us.
Finally we have our final configuration and have started wiring the 'bot up, however time has escaped us, and it's time to wrap up for the evening. Tomorrow morning we'll finish wiring the 'bot, and with any luck get it driving!
Tags: build, beetleweight, Hex1, featherweight, ii3, hobbyweight, nn2
Tonight's efforts were predominantly directed at the twelve pound drumbot Nihilistic Naysayer 2.5, which sustained damage back at the Franklin Cup at the hands of Fiasco, which damaged a drive wheel. Our goal tonight is to swap the dead wheel and make sure the speed controllers work, now that we've got the hang of programming and calibrating them. Hit Back after viewing an image.
Before we get started on the hobbyweight, we had a quick test-fit of some parts that came in from McMaster today. This is the weapon 'hinge' for the hammer that will go on top of the beetle walker. We still haven't quite figured out where the servo will go that will power this setup, but one thing at a time.
The first thing we did was extract the damaged drive motor. You can see here that the can took a hit, which crunched a magnet. Even after cleaning out pieces of broken magnet and roughly tweaking the can back into shape, the motor was jammed, so it went in the Pile o' Used Parts.
Given that the motor had locked up, we were concerned about the speed controllers. A while back we had tried programming them without the card, and it had not gone well. Now we had the card we decided to try again. The first speed controller wouldn't calibrate though, and despite numerous attempts, we assumed that half of the FETs had blown up, as it would work in one direction, but not the other. Another piece of kit is relegated to the PoUP.
After successfully calibrating and programming the second speed controller we had a brain wave! These speed controllers can be programmed to only run in one direction, although obviously we don't want that, so maybe we had inadvertently set that last time we attempted to program them with the transmitter? We grabbed it out of the PoUP and hooked the card to it. Sure enough, that's what happened. After setting the parameters and re-programming it was working fine - hurrah!
These were the replacement motors we had ordered, but had managed to mess up - the diameter is larger than we had wanted, and they won't fit inside the nifty FingerTech wheels like we wanted. We debated ordering different motors, but the likelihood of finding one that would reach us in time was slim, so eventually we decided to go with what we have.
We used the foam tape trick again to build up a tire around the motor. It didn't hold up to Fiasco last time around, but what are the odds we'll fight that 'bot again? 1 in 16 we guess, but last time the 'bot was essentially immobile - this time it will drive! If we can keep the weapon pointed at the opponent, that means the wheels are out of the way.
A fresh layer of grip-tape was applied to both drive motor/wheel combos, and we turned our attention to the insides. Having yanked the drive speed controllers to test and program them, we decided to stop for a moment and reconsider placement of the internals. For Franklin we had to use Lithium Iron Phosphate batteries, which are considerably bulkier than LiPo ones, but there's no such restriction at Motorama, and we're free to use a smaller, lighter, Lithium Polymer one.
Here's where we wrapped up for the night, with a fresh layout in mind, incorporating the 4S LiPo pack, and a properly mounted power switch. Tomorrow we'll reconnect all the wiring, and see if our freshly programmed speed controllers can make the 'bot move. The brushless setup we (almost) have working in the 30lb'er uses the same speed controllers mated to four G25 motors theoretically rated to 600W, albeit with some gearing. The two motors in this 'bot are rated to 800W, but there's no gearing, as the motor is the wheel - fingers crossed it works tomorrow!
Tags: build, beetleweight, Hex1, hobbyweight, nn2
We need to stuff a bunch of things into cases and head to the airport, but before we do that, here's a quick shot of the fleet for Franklin. Hit Back after viewing an image.
Here's the fleet as it stands right now (clockwise-ish from the top: Formidable Fustigator 2.0 - 30lb Featherweight, Malicious Mule - 1lb Antweight, Steel Stiletto - 12lb Hobbyweight, Nihilistic Naysayer 2.5 - 12lb Hobbyweight, and Belligerent Battler 1.0 - 3lb Beetleweight in the middle.
Tags: Franklin, done, ii2, nn2, ss, mm, bb1
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
We actually took the night off last night, because (a) we were tired, and (b) we have two full build days before we have to pack up and head to Philadelphia. This morning we hit the ground running, to see how close we could get to finishing the rebuild of Nihilistic Naysayer 2.0. Hit Back after viewing an image.
The To Do List has a couple of new entries after finding out on Monday night that the drive motors were longer than we'd designed for. We think we can work with it though, and we're hoping our batteries show up soon! Time to get to building!
We let Milly loose on the remaining side wall slot, so that was something we could cross off the list. It'll also let us paint the chassis components later today.
We need a new drum axle, as this time it'll actually fit into the side rails to decrease the likelihood of snapping the bolts that hold it in place, so it needs to be a little longer than the previous one.
Milly has finished re-slotting the center wall, and as you can see the drive motors fit a lot better now. We were a bit concerned about the screw holes for the right drive motor wall, but we were able to drill the just far enough away from that hole that they're good.
It's not very often we have to tap steel, and we remember this being a pain in the rear end last time around, but truthfully tapping the shaft for 1/4"-20 bolts was pretty easy.
Ta-daa! We drilled the bolt holes out to 3/8" going 1/4" deep into the side rails, and after a touch of sanding the shaft fits nicely. Hurrah!
The drive motor walls/mounts have been drilled and countersunk for the drive motors, and they actually came together fairly easily, despite being metric.
Here we have the drive motors installed, and you can see the spacing to the side rails is spot on this time around. We need to bore a hole for a bearing in the side rails, though, to support the outside of the motors.
Meanwhile, on the business end of the 'bot, we've touched up the positioning of the weapon motor pulley, and drilled and tapped for a #6-32 'set screw', except we don't have any, so we put in a normal screw and Dremelled it down.
Rats! When we cut the new rear top and bottom plates this morning we tripped up, and cut the 3/16" too short. Time to re-cut them and re-paint them, except we're out of paint, so it's also time to make a quick run to the store.
When we got back we set Milly up with the job of milling a circular pocket in the side wall for the drive motor bearing. Two things wrong with this photo: (1) The circular pocket is somewhat less than circular; and (2) the pocket is on the wrong side of the wall! Doh. Okay, so we adjusted the backlash a little and gave it another shot.
Second time we had a respectable pocket, so we pressed in a bronze bushing, drilled to 7/16", and the motor fitted nicely! We will need to trim the shaft on the motor a little, but that's an easy job. The 'bot is finally starting to come together.
Here the front wall was been drilled and tapped, along with the center wall, and next we move on to the middle wall.
After tapping the middle wall and drive motor mounts, we're able to attach the front and rear base plates, and all of a sudden this is beginning to look like a 'bot! Which is good, because it's getting late ...
The side rails are given a coat of primer, and we take a break for something to eat. Steak and salad! :-)
After dinner, we try to figure out where the internal components are going to go, as we've had to re-jig the dimensions of the 'bot somewhat. We think we can just about cram the drive and weapon ESCs in with the power switch, leaving the rear compartment for the A123 battery packs.
We haven't quite made it to wiring things up yet, but we're going to have to take the fans off the drive ESCs in order to make everything fit - hope that doesn't become an issue!
To wrap up the night we put coats of black paint and clear enamel on the side rails and call it a night. Tomorrow ought to be a pretty exciting day! :-)
Tags: build, hobbyweight, nn2
Phew! We have three 'bots ready for NERC's Franklin Cup this coming Saturday, and one more missing a wheel but essentially done. Give that we have two and a half evenings plus one full day of build time left, we need to decide what we want to focus on. We can either work on the antweight, in a field of a dozen competitors, or we can put our time and effort into the hobbyweight, which is up against four other contenders in the weight class, including another of our own 'bots. Frankly, it's been so long since we earned a trophy that we're going to take the route with the numeric advantage, and work on the 12lb'er. Hit Back after viewing an image.
Here's the carcass 'bot we're rebuilding - Nihilistic Naysayer 2.0, which took a few hits at Motorama 2012, breaking the weapon shaft and crippling the drive train. Hopefully the improvements we're putting into the rebuild will beef it up some.
This what we have after taking the 'bot apart - a number of damaged frame pieces, a pretty solid drum, and lots of room for improvement! And so we move forward, keeping the drum, weapon motor and speed controller, and not much else.
Here's a quick test-layout of the new chassis and components. The 4S LiPo battery is being replaced with 5S of LiFePO4 cells; the drive motors are going brushless and will be essentially the hubs of the wheels, and the frame should be somewhat sturdier.
Here we've milled slots in the 1/2" 6061 outer walls. The front and middle walls don't look quite right here as they need to be slotted too.
And indeed, here's Milly working on the polycarbonate middle wall. We like working with polycarbonate and UHMW because things go so much faster than when working with aluminium.
With the middle wall slotted, we realize we've made a mistake. Note that the weapon motor shaft is off-center? We cut the slot 1/4" deep, rather than 1/8" - oops! Luckily this ought to be an easy fix.
This is a quick test fit of the drive walls which have been drilled and tapped. The drive motors should end up bolted directly to them, and also need a slot for them in the center wall.
Originally we were planning on casting 40A durometer urethane onto the drive motors, but we don't have time for the Franklin Cup to figure all that out, so here's our 'brilliant plan' instead: we applied five layers of double-sided sticky foam tape to the motor, and then on top of that we added a round of traction tape. In theory the foam tape ought to have some give, like a tire, and the traction tape should - well - give us traction! The traction tape pretty thin, but we have 60 feet of it, so we can afford to replace it between matches.
And this is right about where we see the fatal flaw in the plan. Somehow we messed up the design, because the motors are half an inch longer in real life than we designed for. Argh! If we move the drive walls a half an inch each, we won't have space for our battery packs. Argh! We really want this to work, so we pause to consider our options ...
We decide to press on. We're going to move the drive walls, and order two 2S A123 packs that will fit in the remaining space and run in series. We're dropping 20% of the voltage, but on the other hand, it'll work! So we painted and counter-sank the top and bottom panels. The rear panels will need to be trimmed once the drive walls are moved.
We're about out of time for tonight, so we decided to throw the parts on the scale and see how things look. 11lb 5.6oz with all the existing parts bar a few screws. Even switching the batteries for heavier A123 cells we can still make this work - it's just going to be a matter of time.
There's a saying that goes "Work expands to fill the time available". We don't believe work can possibly contract to fill the time available so looking at our To Do list, we'd better hope we can make good use of our two evenings and one day of build time remaining!
Tags: build, hobbyweight, nn2, mill
We were fairly pleased with how the UHMW drum on Nihilistic Naysayer 2.0 held up at Motorama 2012, but the drum shaft was an issue, and the drive train was pretty poor, so with these two issues to fix in mind, we went back to the drawing board, and set about redesigning the hobbyweight. The shaft ought to be an easy fix, but how to make a simple, yet robust, drive train? Hmm ... To Hit Back after viewing an image.
First upgrade is the side rails, going from 3/8" 6061 aluminium to a full half-inch. Otherwise the shape is roughly the same, although we did make sure to make them interchangeable, so we can have three waterjetted, and the third can be swapped in for either side.
The rear wall is a piece of 1/4"-thick 6061 pipe that we already have handy, although it will need to be trimmed down, as the rear of the 'bot is shorter than the front section, which is the same height as the current version. The center wall is half-inch polycarbonate and the front wall is quarter-inch 6061 - when our drum came off in the first match at Motorama, it hit the polycarb wall we had in version 2.0 and shattered it, so an aluminium wall ought to hold up better. And no holes this time, just a solid piece.
We started with eighth-inch polycarbonate top and bottom panels, but towards the end of the redesign we realized we could afford to go with 6061, so we'll do that. The dividing wall and weapon motor mount are reused from the current 'bot.
So here's what we're thinking for the drive train: take two Turnigy G32 600kv Brushless Outrunner motors, which have an outer diameter of 42mm (1.65") and cast some 40A durometer urethane onto the can, for a final diameter of two inches. Then mount the motors directly to the drive walls, add a bearing for the shaft on the other end, and hook them up to a pair of Turnigy 60A Reversible Brushless speed controllers.
If the kv of a motor (number of revolutions per volt) is 600, the torque (in inch-ounces per amp) is equal to 1352/600, or roughly 2.25in-oz/A. We know from the product page, that the max amperage is 60A, and because we want to take this 'bot to NERC's Franklin Institute, we need to use Lithium Iron Phosphate batteries instead of Lithium Polymer, which have a voltage of 3.3V per cell, so let's say a 4S pack, or 13.2V. With these numbers, we can head over to the Torque Calculator and see where we're at. Big thanks to Gene Burbeck for guiding us through the drive train math!
We set the weight of the 'bot to eight pounds, because most of the weight of the drum will actually be resting on the front skids. The torque required to spin the wheels is less than half the maximum amperage, so in theory the 'bot ought to move. Note the insane top speed of 47mph - there's no way we can drive a 'bot that fast, so we're going to set the maximum rate on the radio to 25% of normal. This will cause the ESC and motor to work harder than simply 100%, but a 12mph 'bot is significantly easier to control than a 'bot at four times that speed! The caculator says we need just over 50 amps peak, and the LiFePO4 batteries have a constant current output of a little over 60A, so that's fine. The only issue really is that the Amp-Hours needed is quite high for a three minute match. LiFePO4 batteries come in 2.1Ah versions, so we're going to go with one of those in the design.
The weapon motor and transmission are transplanted straight from the current 'bot, as it seems to work well, but we will be making a new drum shaft, as it needs to be a bit longer to sit in the pockets in the half-inch outer rails.
This is the majority of the internal components - the blue brick is the LiFePO4 battery, the green blocks are drive ESCs, the red block is the weapon ESC, and we've mounted the Whyachi MS05 power switch to the center wall.
After tallying everything up, we've figured we can definitely switch the top and bottom plates to 6061 aluminium, so here we are!
Except with team colours applied, of course! And yes, thanks to Jason Ribeiro for the information on casting urethane, which means we can have purple wheels ;-)
Tags: design, hobbyweight, nn2
Yesterday was a fun day! We had nine matches, and still have two 'bots in the running as of this morning, although one of them needs a fair bit of work done, so we're up early for breakfast and coffee, and headed to the Farm Show Complex at 8am, to try and beat the mess we encountered yesterday morning. Fortunately we found a decent parking spot this time, and headed in to fix up the beetleweight and check on the hobbyweight. Hit Back after viewing an image.
First order of business - other than coffee - is swapping out the drive and weapon motor speed controllers in Didactic Duelist 1.5 as the original ones all seemed to have burned up in our match against Shame Spiral yesterday. We pulled the BB3-9 controllers from the defunct Unlettered Understrapper 2.5 and those went in without a hitch, but we didn't have an exact replacement for the brushless controller, although we did have a reversible 60A controller spare. Back when we were building this 'bot we tried using a 35A car speed controller without much success, so we were leary of this one, but after hooking everything up, it seemed to work fine, so okay.
By 9am we'd completed the repairs to the beetle, and most competitors had returned to the arena area. The noise levels grew as the morning went on, until finally the competition was on again! We were the second and fourth fight of the morning, so we were glad to have gotten here early and already had everything charged up. It didn't take long before it was time for our first fight - Nihilistic Naysayer 2.0 versus Placebo:
Whew! The blade Ravi has on Placebo certainly chewed our hobbyweight up nicely! Again, the drum shaft came loose, and one side of the drive appeared to have given out again, so we tapped out. You can also see in the photo that the back wall came loose too, but that's our fault for using bolts that are too short. Lessons learned for the next version ...
We didn't have too much time to mourn, because we're up again - this time for Didactic Duelist 1.5 versus Chobham 2.0:
One side of the drive on our beetle seemed to be out at the start of the match, but despite that we were able to put up a pretty good fight, and it was a fun match! Ultimately the Judges gave the decision to Chobham 2.0, and so there we have it - our competition is done! We still had the rest of the day, though, so decided to see what we could do to repair Steel Stiletto and Nihilistic Naysayer 2.0 and maybe get them to face off later in the day.
These are the trophies for the event - alas, we weren't going to be taking any of them home this year, but there's always next time :-)
Here's what's left of the fleet now our matches are done. The circular Poor Punctuation 2.0, the tracked Unlettered Understrapper 2.5 and the large Formidable Fustigator 2.0 are all in pretty poor shape, but the rest are actually in decent shape, and with some tweaks could fight again.
Speaking of fighting again, we spent the rest of the morning and early afternoon swapping motors and controllers in Steel Stiletto, and bolting Nihilistic Naysayer 2.0 back together, and decided to have a grudge match, to help the event organizers fill in some of the dead time that tends to crop up towards the end of the event while the remaining competitors are using their guaranteed 20 minutes between matches to repair and recharge.
The drumbot got one good hit in on Steel Stiletto, but once again the drum finally came undone, and I also managed to wedge myself into the seam at the side of the arena, so this match went to Lauren's Steel Stiletto - next time ... ;-)
As the event was winding down, we cleaned up the pit space, and packed up the 'bots. Once the matches came to an end, it was time for trophies and prizes.
With the awards done, it's time for some forced labour! Well, not really forced, a bunch of the competitors hung around to help take down the big arena, and after a couple of hours it had been stowed in the Bensons' trailer, ready for the trip back to Massachusetts, and all that was left to do was throw our stuff in the 'BotMobile and find out where we're all heading for the End Of Event Dinner.
Which was, of course, Texas Roadhouse! The dinner is always great fun, with the competitors and event organizers able to relax after the long weekend and chat with each other - about robots, typically :-) After a good steak and better conversation it was time to bid adieu to our friends, and head back to the hotel. Another great event is done with, and we need to rest up for the drive back.
P.S. We didn't get to see any snow in Harrisburg, but it snowed Sunday night in Virginia, and we did get to see plenty of snow on the drive back, so Mission: Accomplished!
Tags: motorama, competition, beetleweight, hobbyweight, dd1, ss, nn2
After a restful night, today's the day the Big 'Bots fight (and hopefully win!) so it's time to throw on some clothes, find some coffee, and get the rest of the fleet through safety inspections. Having decided to leave the Sportsman alone, we didn't have any last-minute building to be done, so we decided to head in later than we've done in previous years - that was a mistake! We got to the Farm Complex about 9am, and the main parking lot was already full! We were herded over to a secondary lot and took a bus to the main event complex. Hit Back after viewing an image.
By the time we arrived at the pit table it was pushing 9:30am, and most competitors were already here and going through safety inspections. Lauren took Steel Stiletto over for a safety check, and passed without any issues. I took the two beetles and Nihilistic Naysayer 2.0, and again we had no worries getting through safety.
That left the thirty pounder, and we had actually done some last-minute meatball surgery, as the hole we'd milled in the front wall wasn't exactly lined up with the path of the blade, and with Milly 1500 miles away, back in Texas, we took the easy way out and cut the front wall with the jigsaw. After that, the safety inspection was fine, and we were ready to compete!
It typically takes a while for things to get going, the first morning of the Big 'Bot event, and this year was no exception, but eventually the Drivers Meeting was held, and the crowd began to assemble in the stands, as the brackets were being drawn up.
It seems like we usually miss out on byes at Motorama, but this year Didactic Duelist 1.5 and Nihilistic Naysayer 2.0 both had byes, and yikes! Formidable Fustigator 2.0 is the first match of the event! With all the 'bots charged up, we steeled ourselves for the competition to begin!
Here we go with the first match of the event - and it's not looking like a pleasant match-up! Formidable Fustigator 2.0 versus the full-body spinner of Tetanus:
Thanks to Mike for the video. Ouch. Pretty much a repeat of what happened to us in our second match last year, but hopefully we'll be able to patch this up and run the featherweight on two wheels for it's next match. In theory the two remaining omniwheels ought to let us move around the arena. We checked the brackets, and Didactic Duelist 1.5's bye just went by, so up next we have our oldest 'bot, Unlettered Understrapper 2.5 versus SID (Sadistic Infernal Device):
Thanks to Kyle for uploading this video. Yay! A win! After eight years we finally get the 'bot into an arena with a working weapon and come away with a win - neat! At this point we have a bit of a breather before we need to load up again so the 'bots are back on the battery chargers, and Lauren's on her way back from hunting down some lunch. Nihilistic Naysayer 2.0 has a bye, so up next we have Steel Stiletto versus the old warhorse War Drums:
Thanks again to Kyle for the clip. YAY! Steel Stiletto beat War Drums on a Judges' decision, after a couple of decent slams dislodged the two rear wheels from War Drums, and the front wheels were looking a bit wobbly too! Despite the couple of initial hits from War Drums, we couldn't find any damage back at the pit table, so the 'bot was put on the charger, and we scanned the brackets for our next fight.
There's plenty of activity in the seconday pit area, with 'bots being repaired and charged as the day went on. It's great to see so many familiar faces, and the spirit of cameraderie is evident, with builders helping each other get their 'bots back together - sometimes the driver who just destroyed you is the first one to offer to help!
There was a bit of downtime for us before our next match came up, which was going to be Unlettered Understrapper 2.5 versus Maniac Kathy:
The carcas of Unlettered Understrapper 2.5 after the beating it just took from Maniac Kathy. Suffice it to say, with one win and one loss, we're happy with this old 'bot, but it's time to put it out to pasture. The insides are in good shape, but it can't be fixed up for another match, so we forfeited the next match against Ripto 3.0 and turned our attention to the 'bots that were still running.
Didactic Duelist 1.5 had been slated to fight Traumatizer in the beetleweight brackets, but due to damage Traumatizer received in its first match against Revenge of Dr. Super Brain, it had to forfeit to us. Our next match was going to be in the hobbyweight division, putting our drumbot Nihilistic Naysayer 2.0 up against another veteran 'bot, Alan's Zandor:
Again, thanks to Kyle for the video. A lot of folks on the NERC Forum were skeptical about the UHMW drum, and as it happened, there was a failure, but not of the drum itself - but the bolts holding the dead axle sheared after a weapon-to-weapon hit with Zandor, and ultimately the drum separated from the 'bot. Back at the pit table we quickly extracted the sheared bolts, and replaced them. The front wall had taken a hit from the drum as it separated, and the polycarbonate had shattered on one end of the wall, so the 'bot was a bit rickety, but lives to fight another match!
Up immediately after the drumbot was Steel Stiletto, versus the nasty spinning bar of Fiasco:
Thanks again to Kyle for the video.
Steel Stiletto took a fair bit of abuse from Fiasco before breaking it's weapon, and at least one of the speed controllers went up in smoke, leading to the tap-out. Lauren set about disassembling the 'bot to see if we could get it back up and running for it's next match. After tinkering for a while, we weren't going to be able to make the repairs needed in time for its next match against Placebo, so with a 1-2 record, Steel Stiletto is out of the competition. We will try to finish the repairs though, in case there's an opportunity for a rumble or grudge match tomorrow.
Next into the arena we have our damaged featherweight Formidable Fustigator 2.0 going up against a Canadian saw-bot by the name Gloomy:
Once again, thanks to Kyle for the video. Two things about this match: first, we actually went the distance - the full three minutes; and second the weapon spun up which we were very happy to see! Even though we didn't do a whole lot of damage to Gloomy we were able to knock his saw blade off, and by spinning the 'bot (the DeWalts were in high gear) we got a couple of good thumps in for good measure, but at the end of the day the Judges gave the match to Gloomy, rightly so.
Here's the carcas of Formidable Fustigator 2.0 following its match with Gloomy. Note the very clean cut on the bottom-left of the 'bot: if that cut had been on the right side, there would have been an interesting circumstance - that's where the batteries were! As it is, there's a number of chewed up power and signal cables in there, so the post mortum back at the Build Space will have to weed out the re-usable parts from the destroyed parts.
There was a pretty good crowd in the stands today. Truthfully it thinned out a bit towards the end of the day, but for the better part of the fights today I'd have to guestimate that the stands were 90% full. At this point it's getting on for 5pm, and the fights are spacing out a bit, but it's time again for us to throw a 'bot in the arena; specifically our beetleweight Didactic Duelist 1.5 goes up against the über-speedy Shame Spiral:
More thanks to Kyle for the video. As you can see, Thomas's 'bot completely out-classed Didactic Duelist 1.5 - the weapon died shortly into the match, and after being slammed around the arena, and being left inverted, everything pretty much died after a few more slams, leaving Shame Spiral with a win by Knock Out.
There's your problem! This is the PWM cable for the weapon speed controller in Didactic Duelist 1.5, and as you can see, it's been rubbing against the weapon motor, and that's chewed through the insulation and cable, shorting it, which is why things went quiet in that last match. We also have amber lights on the BB3-9 drive speed controllers, so first thing tomorrow morning we're going to have to switch out both the drive speed controllers and the weapon ESC too!
We hung out for a while to see whether we were going to have any more fights this evening, watching some of the matches, and generally hanging out with some of the great folks running and competing in the event. As 6:30pm rolled by, it became obvious we weren't going to have any more matches this evening, so we tidied up, and called in a reservation to the Texas Roadhouse near the hotel. It was going to be a two-hour wait, so we headed out to the car and ran a couple of errands before dinner.
After dinner it didn't take long for the hectic day to take it's toll, and wrapped up the day with a gin and tonic, and review of some of today's matches.
Tags: motorama, competition, beetleweight, hobbyweight, featherweight, dd1, uu2, ss, nn2, ff2
We were feeling pretty good this morning - we finished a 'bot yesterday, and will likely finish another today. We have everything we need to wrap up the build of our 12lb drumbot, so it's off to the Build Space and here we go! Hit Back after viewing an image.
Here are the last parts, freshly arrived from Australia: two 25A converted brushless speed controllers from Bot Bitz. We were going to try the hacking ourselves, but Hobby King has been out of the source controllers for quite some time.
Here's the last structural work done - the rear wall has been installed. Frankly it was a hassle - as you might expect working with curved parts might be, but it's done, and no: we're not going to paint it.
The BaneBots ESCs need to come out, so here we're disconnecting them from the motors and power connections. The positive leads were on the Whyachi power switch, and very fiddly to get at.
And likewise installing the new ESCs was also quite fiddly - we had to take the bottom plate off to be able to get at the power connections, but with some perseverance everything was hooked up.
This must be a good sign - we had all the motor connections and receiver connections right on the first try. Hurrah!
And with everything installed and bolted down, we weigh in over half a pound under weight - 11lb 7.2oz - so we might want to add more beef to the restraints on the drum teeth, but to all intents and purposes Nihilistic Naysayer 2.0 is done! We haven't taken any video of it running, because quite frankly it's a bit scary contemplating the drum spinning up, but we will take it to our secret testing grounds at some point soon ...
Tags: build, done, hobbyweight, nn2
We haven't made much progress this week, as we've been preparing for a Business Continuity Test that's happening tonight, but we're ready for it, and have a few hours free before the test starts, so it's time to hit the Build Space! Hit Back after viewing an image.
Here are our customary To Do Lists, and as you can see, there's quite a lot to do! Hopefully we can check a few things off today. We're going to tackle some of the jobs that were holding us up with the drill press out of commission.
But now we're back in business! We went through a number of different size and lengths in V-belts trying to find one that worked, and ended up with a 3L330, which is a little big, but works, so we're going to run with it.
Starting out today with the rebuild of Didactic Duelist and we've piled on all the parts, coming out at 2lb 12.6 ounces, so we're well underweight, and can get on with assembly.
First up for the repaired drill press are the aluminium side walls for the Beetle, and it doesn't take too long to drill them out.
Some time later, after a lot of tapping and a couple of episodes of The Invisible Man, we have all the chassis parts tapped, so moving on ...
Lauren popped over, and spent some time working on her antweight Malicious Mule, including a turn with Milly, cutting slots on her chassis parts.
Here we're drilling the mount holes for the weapon motor, using the old mount as a template. That worked quite well.
So we put the parts down in the Paint Shack, and liberally applied the Radicus Purple to the Beetle's frame pieces.
While those parts were drying, we turned our attention to the drum for Nihilistic Naysayer 2.0 and drilled out the mounting holes for the end caps.
A bit of tapping later and we had the weapon pulley mounted to one end cap, and the end caps ready to be mounted, but before we could do that ...
... We needed to mount the teeth!Truthfully it's been a good long while since we worked with tool steel, and drilling the holes in the teeth took quite a lot of time, pressure, cutting fluid, and drill bits, but eventually we were done!
Et viola! The completed drum, ready for installation into the 'bot.
Which was quick and easy, so there we are - after all this time, we've almost finished the rebuild of the drum-bot.
A quick sanity check, to make sure we weren't going to encounter the "Three-Eighths Issue" we had with version one: the teeth do, in fact, clear the chassis, which is a plus :-) And that's where we're going to leave it for today, as we need to go make some dinner and get to the office for the Business Continuity Test. More next week!
Tags: build, antweight, beetleweight, hobbyweight, dd1, nn2
With the drill press still out of commission, we're falling a little behind in our build schedule, but we found a few other things to be getting on with today, including a non-'bot-related job for a friend at work. Hit Back after viewing an image.
A friend at work caught wind of the fact we have a CNC-equipped mill, and asked whether we could help him with a part he needed fabricating. As we can't get on with a whole lot at the moment, we said sure, and invited him round to the Build Space. The part is a mount for a telescope, and he needed some holes milled for alignment.
It took about an hour to learn about the G2 and G3 codes, and eventually had a G-code script written to mill the three holes. There were a number of firsts - for us - in this simple project, including actually milling all the way through a 3/4" piece of aluminium!
Et voila! In fact, David even paid us for it :-) Good thing too, because we were about to take a hit to the wallet ...
We'd received a call from a machine shop in South Austin that we'd contracted to fix up a few parts for us we couldn't manage by ourselves. Here's the weapon for Didactic Duelist 1.5 all MIG-welded up.
And a couple of parts for the hobbyweight Nihilistic Naysayer 2.0, namely the drum on the left, which had been bored to 1/2" to fit the endcaps, and the rear walls on the right, cut from 4" pipe. Unfortunately the bill for these parts wound up being double the original telephone estimate, so we weren't real thrilled about that, but the work was good.
Here's one of the endcaps in place, although we can't drill and tap it at the moment - hmph!
Same deal with the rear wall ... we sure hope one of the 2L V-belts we ordered from McMaster will fit the drill press when they arrive on Tuesday!
With the exception of a few bolts, we're at 11lb 2.4oz out of the 12lb limit, so we have plenty of weight free on the 'bot we can invest in securing the teeth to the drum.
Turning our attention elsewhere, and we're following some advice from the NERC Forum to switch the output on the weapon motors to decrease the leverage on them and their mounts. Here's one of the weapon motors disassembled.
And we used the arbor press to push the shaft through to the other end of the motor can. This took more force than we would have thought - the shaft is a pretty tight fit in the can, but that's a good thing!
We added a couple of new flats to the shaft for the setscrew and collar. We can reuse the flat already on there from the shaft collar for attaching our pinion gear later.
And we're halfway done. The motor on the left is the adjusted one. We just need to follow the same procedure for the one on the right. Those magnets are really very strong! To reassemble the motor we just put the can in the vicinity of the windings, and everything jumped into place!
And finally two adjusted motors with their mounts attached. We need to add spacers for the pinion gears, and re-attach them to the walls, but that's a task for another day.
Last photo of the day, and it's a Pile-o-Parts we just happen to have sitting around the Build Space ... we wonder if we could make anything with these ...
Tags: mill, build, beetleweight, dd1, hobbyweight, nn2, fairyweight, ff2
Still feeling slowed and sluggish from this cold, we spent most of the day under the care of our favourite Alka Selzer Cold medicine, but by mid-afternoon felt like going and being quarantined in the Build Space - who knows, maybe we could screw some screws in or something. As it happened we were able to do a little more than that. Hit Back after viewing an image.
After rummaging around we found some more ring terminals, installed them on the drive ESCs for the the hobbyweight drumbot and suddenly we were ready to see if we could get the wiring finished up so the 'bot would be driveable.
After connecting and tidying the drive ESCs, we were able to package them rather neatly into the space between the gearboxes and the middle wall, so that was looking good.
The rest of the wiring, however, was not quite as neat - crammed into the battery compartment in the top-left of the pic. Everything fits, but only just! We have a Whyachi MS-05 power switch, weapon motor ESC, battery, receiver, and common ground all stuffed in there.
But, at least everything's wired correctly! The power lights at the bottom of the picture are on, and nothing exploded, so hurrah! We also did a wheels test, and found one of the ESCs had been connected to the motor wrong - it was going in the wrong direction, so we stopped a moment to fix that.
The top plate was then marked, drilled, and installed - we were ready for a test-drive!
What the short video didn't show is that we were having the same issue as the first version of this 'bot: the drive would keep cutting out, again presumably because we're sending the BaneBots BB-12-45 ESCs into thermal shutdown, with high amp draw due to friction in the drive train. In the last version we got around that by switching to Victor 883s, but this time we can't do that, because there isn't enough room inside the 'bot for them. Instead we've ordered some Turnigy TY-P1 25A Brushless ESCs which we're going to hack into 25A brushed speed controllers. Let's hope they come back in stock soon!
The scale says 13lb 14oz, but of course that's with the huge piece of 6061 aluminium tube on there - we'll only be using about eight ounces of the pipe, so we're expecting to be a bit under the 12lb weight limit.
For fun we pressed the tool steel teeth into the UHMW pipe to verify the fit. We think we've located a local machine shop that can turn the inner diameter to 2" for us, so hopefully we'll get out to see them some point soon.
Just verifying we have all the parts we need - axle, end caps, pulley, washers, tube, teeth, bolts - check!
One more sanity check - the tube and teeth are 4" diameter - there's 2.25" from the shaft to the front wall. We're not making the 3/8" Mistake again with this 'bot!
Having run out of things to do with the drumbot, we turned our attention to the redesigned beetleweight. Here we've laid out some parts, just to remind outselves of what the plan was ...
... and the 'bot ostensibly looks like the previous version, although this time the wheels will be on the outside, rather than inside.
All our 1/4" polycarb and 6061 aluminium have been marked up and punched, so now it's time for our favourite task: drilling and tapping!
So we procrastinated and did some counter-sinking instead :-)
We did actually get off and running with the drillings, and then heard a twang from the drill press: the belt - which is the eleven year-old original - had finally given up the ghost on us. Still ... 11 years is a pretty good run, don't you think?
We had finished drilling all the polycarb pieces, so we tapped them, and did a little assembly.
Coming together nicely. We'll try to locate another belt tomorrow, and in the meanwhile, it's time to head back inside and warm up with some hot chocolate, more Alka Seltzer, and bed!
Tags: beetleweight, build, dd1, hobbyweight, nn2
Unfortunately we're at the end of our Christmas holiday, and still suffering from a horrendous cold, but we wanted to see whether we could get the New Year off to a productive start none-the-less. We elected to see whether we could get our hobbyweight drumbot to a driveable state. Hit Back after viewing an image.
Our starting point for today is this 10lb 8.4oz pile of parts. This pile doesn't include a rear wall, power switch, drive ESCs, or fasteners, but we think we ought to be able to accomodate those in the remaining one and a half-ish pounds.
Today's main goal is to get the 'bot driveable. We started by trimming down the motor walls, as they were about a quarter-inch too high, and trimming off the excess bolts, etc. Next we moved to the drive shafts.
There may have been a more elegant way of doing this, but we didn't want to take the whole motor apart, so we broke out the Dremel-a-like and went through a few cutting discs trimming the axles.
After pinning the axle extensions, we drilled a capture hole for the bolt that holds the wheel on the axle and installed the wheel, before remounting the whole assembly back into the 'bot.
What this picture fails to capture is the frustrating half-hour we spent trying to get this assembled. The weapon motor is effectively permanently installed to it's mounting plate, the #6-32 screws that mount the weapon motor plate to the cross-piece interfere with the drive motor wall, and the 1/4-20 bolts that mount the drive motor wall are somewhat inaccessible behind the weapon motor! But we perservered, and eventually everything came together.
After putting the frame back together we spent some time checking for binding in the drive. This is a long-standing issue with most of our 'bots - friction in the drivetrain - because we don't quite get things perfectly true after drilling, tapping, etc., but eventually we found the magic combination of bolt tightening that kept things moving.
So time for a bench test of the drive motors. With a battery to the ESC, and one feeding the receiver via BEC we were able to verify both HandiWorks motors ran okay, without binding on the frame - hooray! Although this is a wheels-up test of course: things may be different with the wheels on the deck - we'll see later!
Quite a bit later, apparently, as we're out of ring terminals so we can't hook up the drive ESCs, and it's about time for dinner. We did install the weapon ESC and verified it was operational and spun the motor in the right direction. The ESC is not reversible - we do have one that is, but it doesn't fit neatly in the 'bot, so we'll save that for version three!
We had a few hours available this afternoon, and so decided to spend them working on the drive train for Nihilistic Naysayer 2.0. The first version had Handiworks drill motors, essentially unmodified, and the gearbox on one of them had been smashed to pieces back at Robothon 2010, so we decided to make tougher ones. Hit Back after viewing an image.
You know, we're thankful this isn't a video blog, because the fifteen minutes we spent trying to get the spring clip off the shafts of the Handiworks would have been awfully embarrassing to post! But we persevered, and soon were able to get the Handiworks disassembled, and the gearbox components put into their plastic housing.
Although the plastic tube was nominally 2" diameter, it was oversized, so we started by sanding down two flats. It was going slowly, and it took a bit before we remembered Milly was sitting in the corner! Two gearboxes flatted in no time ... we've got to work on getting up to date, and not trying to do everything the "old school" way ...
The shaft seemed awfully hard to crank by hand, so we decided to apply some juice and see if the motors would actually run. Thankfully they did, although it remains to be seen whether the friction in the finished 'bot will be too high. There's only one way to find out: finish the 'bot!
Here we have one side assembled - both the bolts and the output shaft need to be trimmed down, but it seems to fit okay.
And ta-daa! Both drive motors installed. Next time we'll trim the shafts and bolts, install the wheels, and maybe even wire up a speed controller or two, and find out whether the rebuilt Handiworks are up to the task of pushing the 'bot around ...
"So much time and so little to do. Strike that. Reverse it."
Willy Wonka, Charlie and the Chocolate Factory by Roald Dahl.
We were hoping to be able to give you another "Presenting ..." post tonight, but it didn't quite work out. Today was a day of tackling challenges, and being beaten soundly by them! We didn't take photos of everything, but enough to give you a flavour of what went on today. Hopefully tomorrow will be über-productive. Click Back after viewing an image.
First up, milling slots in the UHMW pipe that's to be the hobbyweight's drum. This operation at least went without incident.
Here we realized that the teeth are wider than we thought, having ordered 3/4" steel, but received 7/8" steel. We do have the clearance in the 'bot for the width, but the question is wether we have the weight. We may wind up having to cut the teeth back a bit.
Milly seems to be cooperating with us today - here we've loaded one of our new endmills into a collet and cut a quarter-inch slot in the front and middle walls for the weapon motor mount.
At this point we'd just finished recharging the two 4S packs that go together in series to power the featherweight's weapon, and plugged in the 6S drive pack, intending to recharge after our recent drive test and go again, but what's this? "Voltage error?" Darn ... inspection of the pack showed it to be a bit 'puffy' - not a good sign with LiPo packs, and the voltage read 14V, meaning the 6S pack looked to be a 4S pack. Drat. We hopped online and ordered a couple of spares to be delivered to our Motorama hotel - so much for test driving. To really hammer homethe misery we soldered connectors to a new weapon ESC for the 12lb'er - misery loves company.
While soldering we had an "Ah-ha" moment and figured out what we'd done wrong with the antweight - we used the wrong weapon shaft pulley which is why the belt seemed so loose. To use the 24-tooth pulley we needed to enlarge the space in our bearing block we made a while back, which we did, and pinned the new pulley to the shaft.
This serene photo does nothing to convey our mounting frustration trying to re-pin the weapon motor pulley to the weapon motor shaft. We went through about a dozen rollpins, and finally - just as we seemed to have cracked it, when the motor pulley pinged off and across the build space for the umpteenth time we threw our hands up and put the 'bot aside for the day. We have another motor showing up tomorrow, so we'll re-do it tomorrow.
Back to the drumbot and we re-drilled the new polycarbonate weapon motor mount using the old one as a template. At least that was straight-forward.
With a bit of drilling and tapping the motor mount is done. A minor victory, but a victory none-the-less.
Looking at one of the beetles, and the titanium front fits just right. We're going to ditch the front wheels and just run 2WD on the back with skids up front.
Here's a quick test layout of the weapon blades, and we decided to move to drilling and pinned them to the shaft. That didn't go well, with the drill bit snapping off in the steel rod, so we're going to have to cut another one and start over. Grr.
At least the drive motor axles fit properly, although we have no idea how to mount the Lite Flight wheels, so we may switch them out for some different, beefier ones. We did some other miscellaneous stuff, but nothing that added up to a finished 'bot, so we're going to have food and make it an early night, hoping tomorrow will be better ...
Tags: build, dd1, beetleweight, hobbyweight, nn2, antweight, pp1
Due to some work requirements, we weren't able to get any building in last night, plus UPS were still keeping our missing parts from Whyachi hostage, so we were a bit miffed. Today was quite different, though, because not only did UPS finally drop off our parts, we had the whole evening to work on the 'bots. Granted it was below freezing in the Build Space, but we were determined to keep moving and cross some items off our To Do Lists. Click Back after viewing an image.
Here's one of the more exciting parts that showed up via UPS from Team Whyachi: the hardened steel blade for our 30-pounder Formidable Fustigator 0.9. That's a 24" quarter-inch thick piece of chromoly.
More Whyachi parts - the top and bottom plates for the 30lb'er, cut from 3/16" polycarbonate. We've been really looking forward to receiving these, so we could get on with assembling the 'bot.
Some more parts, although on a different scale. 0.07" titanium front panels for the beetleweight Didactic Duelist 0.9, and three chromoly blades for the 'bot too, also heat treated.
Despite below-freezing temperatures in the Build Space we decided to try and put a coat of paint on some of the featheweight and beetleweight parts. Due to the low light in the Build Space it wasn't until we took this photo that we saw the first coat barely coloured the parts, much less covered them. Guess it's time to give a second coat.
There were a few holes to drill in the top plate of the 30lb'er, to mount the drive motors and wheel walls. We didn't have them waterjetted because we didn't know where they needed to be at the time. It was pretty easy to mark up and drill the top plate, though.
As you can see, this 'bot is bigger than our drill press, so working on the base plate proved to be a logistical challenge, trying to work around the limitations of the drill press to get to the holes we needed.
We chucked up the countersink and went to town on the top and bottom plates. We find countersinking to be a very relaxing operation ... wonder if you can be a professional countersinkerer ...
Now that the top plate has been drilled out, we're ready to give it a coat of paint. The blotches on the camera are condensation on the lens, although we did end up applying a second coat to the top plate. We decided not to paint the baseplate, as it wasn't necessary, and we wanted a way to be able to see into the 'bot after a match.
While the 30lb'er parts dried, we decided to look at the hobbyweight, and work on the gearboxes we're building. Here we've pressed a second ring gear into some delrin tube, and we're collecting up gears to install.
After working on this for a little while we realized we'd made a slight error - the gearbox plates that the motor mounted to should have been a quarter of an inch thick, instead of an eighth of an inch. We'll recut those at a more socially acceptable time to be using the tablesaw.
While we continued to wait for the painted parts to dry, we decided to install some components to the baseplate. Here we've installed the weapon shaft bearing and the strengthener for the bottom plate, along with the lower blade sheath. It all went together easily - bonus marks for waterjetting!
Here's the flip side of the part. The half-inch bolts are just the right size, and the bearing fits very nicely into the base of the aluminium parts.
We couldn't resist test-fitting the blade. We bolted in the weapon retainer, and pressed the shaft into the blade. With the aliminium brace installed the parts seemed reasonably solid, so that's good. Maybe it'll make it past one hit ;-)
We changed tack as the painted parts were still tacky, and decided to sweat some small stuff. We've never done this before, but we installed zipties to the FETs on the Victor 883s for the 30lb'er to try and protect against the two bridges shorting on an impact. It was easy enough, and passed the time while parts were drying.
Here we failed miserably to install a 45A Anderson Powerpole connector to a battery pack. We used to have no problems doing this, but we must have lost the knack. We scoured YouTube for a while, and dinked with a spare connector or two, and finally managed to get them installed.
Our parts are dry to the touch, so we decided to soldier ahead with the assembly. Here we've loosely installed the weapon motor mount and the rear curve wall. We decide to install the rear drive motor next, but a mistake in our design meant the wall and the mount overlapped, and we'd need to clear that up.
Ordinarily we'd have sanded down the wheel mount using the sander, but we realized we had Milly sitting in the corner, so we decided to cut out slots for the motor mount to fit in. At this point we realized it was gone 11pm, and down to the teens temperature-wise, so we called it a night, and headed into the warmth.
Tags: build, ff1, featherweight, nn2, hobbyweight, dd1, beetleweight, mill
We've drawn up an aggressive schedule to wrap up our builds in the week and a half before Motorama 2011, so we'd better get cracking! Tonight we have some frame work to do for Formidable Fustigator 0.9. Click Back after viewing an image.
Yup - drilling and tapping photos. Sorry, but that's the name of the game tonight, so we've marked up our aluminium parts and drilled pilot holes. Now we're moving to a 13/64" drill bit in preparation for tapping.
All right ... we have 52 holes to tape for 1/4"-20 bolts. We have the radio on, and we're timing our holes per song. At the outset we're managing four holes per song ...
... By the time we finished all 52 of the 3/4"-deep holes we were down to one-to-two holes per song. That's a lot of tapping! But hey! It's done, and if our top and bottom plates ever are delivered by UPS we'll be ready to assemble the frame!
After all the tapping we decided to move on to our hobbyweight and work on the gearboxes. We'd made it as far as drilling motor mount holes for the Handiworks motors in the gearbox back plates before we realized it was 11pm already, and we have a busy work-day tomorrow, so we'd better wrap up! Stay tuned for tomorrow's installment: Same 'Bot Time; Same 'Bot Channel!
Tags: build, hobbyweight, featherweight, ff1, nn2
This site contains records of our trials and tribulations in building combat robots. So much to learn, and so little time!