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
After all the problems we had trying to get the pistol radio working with these speed controllers in Intrusive Interloper 3.0 we're going to take a swing at getting it running with the Spektrum radio instead. If that doesn't work, then we're at a loss as to where to go from there ... Hit Back after viewing an image.
But before we get to troubleshooting, we need to sand off the waterjetting tabs on the parts for the beetleweight walker. Now that we're dealing with them as pieces, not just a sheet of aluminium, the realization kicks in: there are a lot of pieces!
And with the last of the sun, we line all the pieces up for some paint - the blue team on the left will get primer and purple, the rest will get primer and black - the metal hexapod will have the same colour scheme as our acrylic one.
While the primer dries we turn our attention to the featherweight's drive pods. Here we've switched from the pistol radio and receiver to the Spektrum setup, and after messing with end points and throttle curves we have this pod running semi-reliably.
With a close-up you can see why this pod runs so roughly - look at the remainder of the teeth on the pinion gear now that we've had a chance to run this pod in for about five minutes - they're grinding away. But on the plus side, at least it's running now. Guess we were slightly off with our motor mounting holes on this pod - drat.
The next two drive pods have zero issues, however, and with a few minutes of breaking in each, they run smoothly, so we install them into the 'bot. The fourth pod was mostly okay, but again had a couple of moments where it took a bit to get it started, so this pod could be an issue. We're still waiting for UPS to deliver our McMaster order so we can cut an axle for the fifth drive pod and try it out.
With four mostly-functioning drive pods in place we turn our attention to wiring. We're going to cram four 2S 2100mAh LiPo batteries in there, as a 2S2P arrangement for the voltage (14.8V) and longevity.
We've also switched the power switch to the beefier one from the previous version of this 'bot, and have started wiring up the speed controllers. Plenty of ring terminals here! But it makes wiring pretty simple. Hook all the reds together and run a lead to the power switch, then add a couple of PowerPole connectors from the switch for the batteries.
Next hook up all the negative leads from the ESCs to a pair of PowerPoles to make the connection to the batteries - nice and easy, which we like!
Lastly we just have to tuck all the radio equipment (receiver, mixer, Y-cables, and PWM leads) into the space that's left between the switch and the PowerPoles. In theory we could ditch the mixer and use the mixing capability with the Spektrum radio, but in order to ensure that when we want to the 'bot to run straight it goes straight, we put the forward/backward on the elevon axis of the right stick, and put the will use the rudder axis on the left stick for left/right. This is the first time we've ever done this, so it will take some getting used to. With the wiring done it's time to take the 'bot for a test run!
Hmm ... not perfect, if we're being truthful. We purposely weren't gunning it, because the Build Space is a bit too messy for a 30lb'er to be bouncing around in it, but it seems that we have 2.5 working drive pods ... we're going to have to put the fifth one together and replace the pod that barely functions, and investigate the dodgy one that works some of the time, but otherwise hey: it moves!
Tags: build, featherweight, beetleweight, Hex1, ii3
Now that we've actually made a start on the beetleweight walker, we need to seriously consider a weapon for it. The plan all along has been an overhead hammer, so we need to work out how to build one and affix it to the body. We've not made a hammer before, so it's been a challenge trying to figure out the best way to put one together, and here's our initial design for it. We wanted it to be able to rotate, to be able to attack on the sides of the 'bot, but that was a bit too much complexity for the first time out. Hit Back after viewing an image.
To keep things simple, we'll start with the top plate of the body. From there we'll put eight one inch long #4-40 threaded stand-offs in, to give us some space from the mess of cabling that sticks up from the top of the controller board.
On top of that is a simple plate to act as the platform for the hammer. This is 1/8"-thick 6061 aluminium, just because we happen to have some (we think) and we'll cut and drill it ourselves, versus getting it waterjetted.
On to the platform we'll mount a couple of bearings from McMaster, good for a half-inch shaft - we can use a piece of the keyed shaft that's already on order for the fifth featherweight drive axle. We also have a couple of shaft collars in there to lock the weapon shaft into place.
There's the shaft, and there's also a 14-tooth #25 sprocket, which will be hooked to the largest servo we ordered a week or two ago, which will be doing the actuation. We're going to write a simple set of moves in the PoMoCo script for Hexy for up, down-front, and down-back.
Couple of things here - firstly the platform has been trimmed, because we don't need those corners sticking out. Secondly we have a piece of 1" 6061 bar, which has a half-inch hole drilled through it to sit on the weapon shaft, and will have the rear rounded off, and a couple of set screws put in to fix it to the axle. In the front of the block there's a 1/2"-13 threaded hole drilled and tapped, into which is the long dark grey cylinder, representing a length of grade 8 threaded rod.
Here's the business end - another drilled and tapped 6061 block with a length of grade 8 threaded rod in it, only this time the two ends have been ground to points. It's not going to hold up super-well, but at least it'll be cheap and quick to replace if it gets blunted. The actual lengths of the rods will have to be determined once the body has been put together, to ensure sufficient clearance. These weapon components weigh close to two pounds, so with the aluminium body we weighed last night, we've used four and three-quarters of our six pound allotment, with battery and electronics left to go. There may even be weight left over for armour ...
Tags: beetleweight, design, Hex1
Time is ticking away before Motorama 2013, and we still have some unfinished 'bots to deal with. There's a 12lb drumbot with a dead drive train, a fairyweight that needs some wiring sorted out, a featherweight needing assembly, and a walker that's still very much in kit form. Tonight we're going to start with the 30lb'er and see where we get to. Hit Back after viewing an image.
First job of the evening is to finish wiring the drive pods for the 30lb'er. We've already tested them to ensure proper orientation, so we have a pair of pods that are wired the same for proper forward rotation on one side, and another pair with swapped leads for the other side. We've marked the drive pods to indicate which is which, so we can quickly wire the spare pod to match as needed.
While we had the pods out, we hooked up the programming card and punched in some values we hoped would work. We've upped the reverse power to 100%, and set it to Low timing (for a low rpm/V motor), and also widened the deadband. It doesn't take long at all to set the values we want with this thing on all four pods - well worth the four dollars to avoid having to try it with the radio and beep codes.
Here we have all four drive pods sitting in place. Before we put over a couple of dozen bolts into this to hold down the pods we realized we needed to calibrate the throttle on the speed controllers, and the calibration button would be under the controller on the baseplate for two of the ESCs, so lucky we didn't bolt them all down yet! Here we had issues though. No matter what we tried, we couldn't get the ESCs to recognize the minimum throttle level (i.e. full reverse). We tried with and without the mixer, and also tried using different channels, but we just couldn't get the beeps. This is a problem, because the ESC needs full reverse to get the 'bot to run backwards. After a couple of frustrating hours, we posted online for some assistance, and moved on to something else.
That something else was punching the waterjetted parts out of the 24"x12" piece of quarter-inch thick 6061 aluminium. We have body parts, seven complete legs, and also a spare foot for good measure.
Here's the remnant the parts were punched out from - this may very well have to go up on the Build Space wall - it's not only pretty, but it's shiny too. We could probably have crammed a couple more parts on there as spares, but hopefully we have sufficient.
This is where we are with a full complement of legs and body pieces: 2lb 8.74oz. Factor in 18 x 9 grams = 162 grams or 0.36 pounds or 5.7 ounces worth of servos, and we still have half our weight allowance left for armour, electronics, a battery, and a weapon. Not bad - assuming it moves!
Now we have no doubt this 'bot will do well - the 'Bot Gods have their blood sacrifice! Actually, it looks worse than it really is, but it has to be done at least once per 'bot, it seems, and this one can be crossed off that particular list ...
On an initial check, we're going to have to clean up the parts somewhat with a file - you can see the leg servos don't quite fit in the thigh piece. We took out a file, and worked on squaring the corners inside the piece.
Success! Truthfully it didn't take very long, and wasn't that much effort, so we ran a file over all the other thigh pieces at the same time, along with one of the hip pieces where the third servo on the leg sits. We're also going to have to run all the parts on the belt sander to eliminate the waterjet tabs, but it's too late tonight to do that - we'll save that for another evening.
Moving down to our smallest unfinished 'bot, and here we have Lauren's fairyweight Tenacious Tinkerbell out for a test drive. We need to tidy up that wiring, but the 'bot is essentially done, and drives fairly well.
We crammed most of the wiring into various nooks and crannies in the 'bot, then added sufficient electrical tape to keep it all in place. Came out pretty well in the end. Not bad for a cheap and simple build. If we had to do it over, we'd probably swap the 10:1 motors for our favourite 30:1 motors, but we already had the 10:1s sitting around doing nothing, so there you go.
And a beauty shot. The CCD on our camera loves distorting colours - the 'bot is really more of a hot pink than a Ferrari red, but oh well.
Just for fun (and seeing as how they're all done except for stickers) here's Lauren's portion of the Team Radicus fleet for Motorama 2013. On the bottom, the twelve pound hobbyweight Steel Stiletto, in the middle the one pound antweight Malicious Mule, and on top the new fairyweight. That ought to keep her busy :-)
Tomorrow hopefully we can figure out the darned reverse on the 30lb'er speed controllers - we'll try using a different radio and receiver, to see if that makes a difference. We'll also run the walker parts across the belt sander and file them all to make sure the tabs fit the slots, and then we still have some work to put in on the hobbyweight to get the drive back up and running. Stay tuned - same 'bot time - same 'bot channel!
Tags: build, fairyweight, teti, featherweight, ii3, beetleweight, Hex1
The goal tonight is to figure out the issues with our beetleweight Belligerent Battler and see if we can fix them up. At the 2012 Franklin Cup, the drive train was very lackluster, and although the weapon was decent, it had issues staying together. Time to put our troubleshooting hat on! Hit Back after viewing an image.
We've deconstructed the 'bot somewhat and found a number of issues - firstly the weapon motors are loose in their mounts, so we tightened up the mounting screws. We also need to have a bit of a test drive to see which motors in particular are giving us problems.
Hmm ... in the video you can see the drive train is actually pretty darn zippy - a significant improvement over it's performance at Franklin. The obvious difference is that we don't have the side walls on, so it stands to reason there's too much friction when the walls are installed and the drive axles are in their bearings in the outer wall.
To that end, we decided to cut off the overhung axle. We broke out the Dremel-ish and in no time had these trimmed down in no time, leaving funky engraved marks in the hubs at the same time. The hubs are pinned to the axles, so no worries about them sliding off the axles. We finally have a decent drive train!
Unfortunately, now the weapon motors don't spin up. Turned out we got carried away tightening their mounting screws, and actually managed to strip two of the bolts for one of the motors, so again came the Dremel-ish to our rescue, cutting slots in the screw-heads, and we were able to remove them. Doh!
The 'bot was fairly underweight at Franklin, coming in as you can see here at less than two and three-quarter pounds, so with almost five ounces to work with, and knowing we're going to save almost an ounce by switching the Whyachi power switch to a FingerTech test unit, we're seriously debating swapping the UHMW side rails for 6061 aluminium ...
But for the meanwhile, we're all patched up and ready to rock! We've tested the drive train and the weapon, and both work fine, so it's time to stick a fork in this 'bot [for now - we'll revisit the 6061 side rail idea another time] and call it done! 50% of the Motorama 2013 is done and ready, and we still have a month to go, so things are looking good!
Tags: build, done, beetleweight, bb1
Today was one of those days where we got a lot done, but with very few pictures to prove it. The goal was to wrap up three more 'bots, and although we fell a bit short of that mark, we had a very productive day. Hit Back after viewing an image.
The weapon motor on Transcendental Terror 2.0 was not spinning up. We'd already identified one wire that was not connected properly, despite our best soldering efforts, and after pulling off the electrical tape, it was pretty easy to spot the same problem on the other two leads.
We broke out the crimper and PWM pins, and mechanically connected the motor to the speed controller. Finally, all was well. Time to bolt on the top plate and take the 'bot for a test drive.
No video at the moment - sorry - but the 'bot is pretty zippy on it's 3S battery and 30:1 HP Pololu motors. Final weight is 144 grams, out of 150 allowed, so no worries there, and the internal components are very tightly packed, so our worries about the side walls pivoting are essentially unfounded.
At this point we switched our attention to Belligerent Battler 1.0, which needs some upgrading done. We neglected to take any photos, but were able to cross a few things off the To Do List.
Switching focus again, this time to the hobbyweight Steel Stiletto. We used hacked brushless speed controllers in this 'bot at the last competition, and they worked fine, but in testing with the gyro we want to put in the 'bot, the ESCs would rhythmically 'pulse' on. We decided to switch to the configuration that worked in our 30lb'er - using Victor 883 speed controllers instead. We also took the time to update the 'bots paint job.
This is as far as we made it tonight - the 'bot is mostly assembled, but needs some additional wiring and internals installed. Then we'll put it through it's paces with the gyro and see if it's more controllable than last time. More to come tomorrow - same 'Bot Time, same 'Bot Channel.
Tags: build, beetleweight, fairyweight, hobbyweight, bb1, tt2, ss
After yesterday we knew we're close with the beetleweight Belligerent Battler 0.9 so first out the gate this evening is to wrap this 'bot up. We have some finessing of the chassis and the wiring to do. Hit Back after viewing an image.
Before we get carried away we decide to check the weight, and there's no worries there - 2lb 10.8oz before wire connectors and screws. We could possibly also add a couple of thin strips of aluminium across the top and bottom of the beater support to keep the walls from flexing out.
One of the issues from yesterday was that the weapon motors were touching the side walls, causing friction. Given that the ends of the pulleys are up against the side walls, we feel we can afford to lose the outer flanges on the pulleys, so we hit them up on the belt sander.
The weapon motors fit much better now that we've trimmed both the pulleys and also the front wall, taking another eighth of an inch from each end of the front wall. The side walls are finally parallel, which we're happy with, so now it's time to move on to our nemesis - wiring!
Part way through we found ourselves having to remove the rear wall to get at the power connectors on the Whyachi power switch, so this is a bit of a hassle, but at least once it's done we won't have to do it again! Fortunately it didn't take very long to get these connections hooked up, and all of a sudden we had another 'bot ready to go!
We have a blue LED as our power indicator, and as you can spot here we're missing one screw in the top panel because the wiring bunched up, so we'll need to tweak the bundles of wires inside there at some point to flatten the top out, but hey - it's done!
Tags: beetleweight, bb1, done, build
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
This time next week we'll be in Philadelphia, but as things stand right now we'll be there mainly as spectators to the Franklin Cup. We have two 'bots that are running, but with issues, and the other four are still piles of parts. We don't usually build on Friday nights, preferring to relax from the week, but we don't have that luxury tonight. We're going to do what we can to get Steel Stiletto underweight, and exorcise the gremlins from Intrusive Interloper 2.0. Hit Back after viewing an image.
Earlier today we took a lunch trip over to see Chris, and throw some parts on the lathe. Chris mentioned he hasn't used it since the last time we were here, which was before Motorama 2012, so it was in exactly the same state as when we left.
We wanted to core the drive axles for Steel Stiletto to save some weight after realizing that the original axles were aluminium, and we had replaced them with steel. We calaculated that a quarter-inch bore would save about an ounce, which helps.
Meanwhile, back at the Hall of Justice ...
First on the To Do list is figuring out why the featherweight drives so poorly. We disassembled the drive train, and found a DeWalt that had siezed up. Not sure if it's the motor or the gearbox, but we swapped it out, and everything seemed to spin nicely.
We hunted around a bit, and found four Victor 883 ESCs that seemed to be in good shape, so if the 'bot is still acting wierd with the replacement motor, we're going to see if we can swap in these in place of the hacked ESCs.
With the 'bot mostly reassembled we took it for another test run, and although all the motors now drive nicely, power to them does cut out from time to time, and the gyro is not working at all.
As things currently stand, we're at 29.2lb, so we do have a little leeway to be able to fiddle with the internals.
Taking a short break from the 30lb-er, here's a test assembly of the beetleweight chassis, with the drive train installed. It doesn't look perfectly square, but no matter, the wheels turn, and that's really what counts.
We trimmed the drive axles on Steel Stiletto in addition to coring them, and our efforts have paid off. The scale reads 11.8lb! Success ... now we have to re-wire a little bit to fit the new 3S A123 pack.
We switched the #6-32 nuts and bolts for the ring terminals to #4-40, and shortened the wires as much as we possibly could. After neatening up the wiring, everything fits nicely, so we took the 'bot for a quick test run.
We had an audience - normally critters are not permitted in the Build Space, but this guy was cute, and kept following us around the worktable, so he got to stay and watch.
Well ... that didn't go so well - one side of the drive train bound on a screw that had come out from one of the broken motor supports, which caused the battery pack to overheat. Hopefully the pack is okay - we'll try putting it on the charger and see if it's still juice-able.
After a decent test run for Steel Stiletto (barring the screw-chain-battery issue) we turned our attention to the thirty-pounder. After a couple more test runs, we decided to eliminate the gyro - we tried two of them, and they both caused the 'bot to act squirrelly, so we've decided to ditch them. We've also decided that the ESCs we hacked are not up to snuff - they keep shutting down - so we're going to switch in some trusty Victor 883s and see if that makes the 'bot more reliable.
With the four Victors in place of the two TZ85As the scale reads 29.4lb, so we can keep the four packs in the 'bot, and hopefully get it running smoothly tomorrow. It's getting late, and although we've put in a good few hours of work, it's time to wrap up for the night, in anticipation of a big build weekend - our last before Franklin - to determine just how many of the 'bots will be up and running for the event.
Tags: build, beetleweight, bb1, featherweight, ii2, hobbyweight, ss
So, this evening we're going to devote ourselves to trying to get the beetleweight closer to assembly and see if we can't get the chassis and drive train completed. It should be a fairly straight-forward assembly, but who knows what fun-filled issues we'll encounter! Hit Back after viewing an image.
We started out with a major math error. The slots for the drive walls, which are a quarter-inch thick, came out too wide. Oops. Ah well, at least it's not a critical error. Moving on ...
Here we've drilled out a 23/64" hole in the side walls for a bearing for the drive axle, and pressed in said bearing on the arbor press. UHMW is such an easy material to work with!
We've pressed the aluminium hubs out of the tires, and carefully enlarged the bore from 1/8" to 1/4" on the drill press. It actually came out well, so we're pleased with that.
Seeing as though we're in a drilling mood, we've also drilled and tapped the rear wall for the Whyachi power switch. This wasn't where we were originally going to put it, but it turns out there's enough room between the two drive motors that we can slot this in here just fine.
The 1/8" bore of the weapon motor pulleys has been enlarged to 4mm, and the pulleys press on nicely. We'll still need to drill and pin them, though.
Speaking of drilling and pinning, here we've pinned the aluminium spacer axles to the drive motor shafts, which involved breaking no less than five 1/16" drill bits! Those suckers are hard! Finally we were able to install the hubs to the axles, without breaking any more drill bits.
Before we get started with assembly we've drilled the front wall for the weapon motor mounts, and put a coat of primer on the front and rear walls, followed up with matt black paint, and a clear coat on top.
While the paint is drying, we've broken out the soldering iron to hook up the drive ESCs to the motors. This went pretty easily, so maybe there's hope for our soldering skills after all!
Time for some calibration and testing. We've hooked up the battery to the two FingerTech TinyESCs and calibrated them, plus ensured that we have them hooked up to the drive motors the correct way. With elevon mixing enabled on the transmitter, we were able to see the wheels both spin the right way, so we're good to go on the drive front. We also hooked up the weapon motors to their ESCs, and run through the calibration steps, which were actually pretty easy. We also took some time to change the configuration via transmitter, working through beeps a-plenty, to set the reverse power allowed to maximum, change the braking option, and get them ready to roll. We also figured out why Poor Punctuation 2.0 failed to spin up back at Motorama 2012: the Y-cable we hacked to fit the 'bot was poorly done, and the signal pin on one end was not locked in place, so never made contact with the plug to the ESC. We tweaked the Y-cable, and verified it was now usable in testing Belligerent Battler 0.9's weapon ESCs.
The paint still isn't quite dry, and it's getting late, so we're going to call it a night, and pick back up again tomorrow evening with the goal of getting this 'bot running around!
Tags: build, bb1, beetleweight
Turns out we have a few hours to build tonight, so we're going to capitalize on that time and see what we can cross off the To Do lists. We want to troubleshoot the featherweight, and hopefully get some assembly done on the beetle too. Hit Back after viewing an image.
The last time we ran Intrusive Interloper 2.0 it was pretty screwy, so we've popped the top to try and find out what's going on. First thing we tried was eliminating the gyro, but we still had issues. The 'bot would simply cut out after a few seconds of driving, then come back to life sputtering, and cut out again. We were wondering whether we weren't giving it enough juice with four motors and just one battery, so we put another pair on the chargers and turned our attention to the beetleweight while they charged up.
Here we've milled some slots in the side walls of Belligerent Battler 0.9, and are trying a test-fit of the front and rear walls. So far so good, but the right wall's slot was slightly off, which warps the frame a little bit. Hopefully when we put the top and bottom plates on they will help to re-align the chassis.
Here we've drilled the weapon shaft holes out to 31/64" and pressed in a pair of bearings. After judiciously applying a file to the ends of the weapon shaft, the beater fits nicely and spins freely - bonus!
Here's a quick test layout of the internals. We have a pair of weapon motors up front, along with a battery and receiver. Next in line are the two weapon ESCs and power switch, lastly we have the two drive motors, motor mounts, wheels, and drive ESCs. Hopefully by the end of Wednesday night we have the whole chassis assembled and we can be dealing with installing these components.
With the extra battery packs charged up, we installed them into Intrusive Interloper 2.0, but still the 'bot was acting squirrelly. At this point we have four possible suspects: the receiver, the V-tail mixer, the hacked ESCs, or the DeWalt motors themselves. Frankly, the ESCs and the motors are the most likely suspects - the ESCs because they're an unknown commodity, and the motors because they've been around the block quite a few times. According to the Tentacle Calculator, each ESC should be pulling up to 20A to spin the wheels. These ESCs are supposed to be able to handle 85A continuously, but of course they were hacked with our own dodgy soldering skills, so that could be the culprit. The motors have been in various 'bots through their lifespan, so maybe the brushes are starting to give out. We'll start eliminating components the next time we work on the 'bot ...
Tags: beetleweight, featherweight, build, ii2, bb1
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
We were really excited by our last beetleweight design but then we got to thinking about the fact we're going to be flying to the NERC Franklin Cup competition, and trying to get a 36" blade in a case would be a challenge. Reluctantly we put Lincoln Limboer 0.9 on the back-burner and set about designing a beetle that would be more flight-friendly. Hit Back after viewing an image.
Here's the basic chassis. The front and rear walls are 1/4" 6061 aluminium; the inner walls and top/bottom panels are polycarbonate. The two inner walls at the front of the render are for the weapon motors, and the two at the back are for the drive motors.
The outer side walls are 1/2" UHMW plastic, waterjet-cut, and milled for the front and rear walls to slot in. We're thinking - if we have weight - of putting a couple of titanium splints on the outside, where the front weapon mount points stick out from the 'bot, but we'll see how sturdy things seem once the 'bot it assembled.
The drive train is unremarkable - 1000rpm gearmotors from Kitbots controlled by two FingerTech TinyESCs, and 2" solid rubber wheels. It won't be the fastest 'bot on the block, but hopefully simplicity translates into reliability.
The weapon is a steel beater, waterjet-cut from a 2.5" wide x 0.5" thick piece of chromoly steel, then milled down to a quarter-inch thich on the outside, and a 5/16" diameter steel shaft welded to the beater (or vice versa, depending on how you want to look at it). The beater is powered by a pair of 2836-11T brushless motors. These motors get 750 rpm per volt, so running at 3S, or 11.1V, the motors will get up to 8,325 rpm. The transmission is a 16-tooth MXL pulley on the motor linked to a 30-tooth MXL pulley on the beater shaft, for an effective reduction of 1:1.875, so the final beater output could theoretically be in the region of 4,000rpm. We're running the motors off reversible ESCs, so if the 'bot is flipped we can run the beater the other way.
Add into the chassis a decent-sized Lithium Polymer battery, OrangeRx 4-channel receiver, and a Whyachi MS-05 switch and you have the gist of things for this 'bot, which we're going to name Belligerent Battler 0.9.
Finally some team colours - the UHMW is black, so we'll paint the front and rear walls black too, and the top and bottom will be purple. We're also going to have to add a mark to the top and bottom so we know which way the throttle is supposed to be for that orientation!
Tags: beetleweight, design, bb1
Ever since the dismal failure of our featherweight Formidable Fustigator 2.0 we've put large blades on the backburner and focused our efforts on simpler, more robust 'bots, but this design crept up on us over the weekend - Lincoln Limboer 0.9! The name is a portmanteau-ish reference to two other large-bladed 'bots: Greenwave (think Lincoln Green) and Limbo. This design is for the three-pound beetleweight class, and is actually quite simple. Hit Back after viewing an image.
We tried a number of base chassis designs, but they ended up being pretty hefty in the weight department, and with only three pounds to work with, we had to keep it lean. This is our final[ish] design, with a 1/8"-thick piece of 6061 aluminium as the base, and four Pololu HP 30:1 motors on 1" wheels.
A 2" outer diamter, 1" inner diameter piece of 6061 pipe is our central dead shaft. The bronze things are thrust bearings, and the pipe bolts to the baseplate with four 1/4"-20 bolts. The hollow core to the shaft is to allow power leads to run out to the drive motors from the two TinyESCs running the drive.
This is the weapon setup with the upper bronze thrust bearing removed for clarity. That's a 3542 brushless motor powering the blade, which is a piece of 0.071" titanium. Bolted to it is a 78-tooth XL timing pulley, which connects to the 19-tooth pulley on the drive motor with a 100-tooth belt. The blade weighs a little over half a pound, so we think that this 40A motor ought to be able to get it up and running without cogging.
Here is the electronics platform bolted to the top of the dead shaft. LiFePO4 batteries in blue, power switch in white, weapon ESC in red, and the receiver and drive ESCs are not shown. The platform is 1/8" polycarbonate.
We selected Pololu 30:1 HP gearmotors for this 'bot, because our original plan of using the copious 50:1 Copals we have sitting around would have meant a 1mph 'bot, which isn't all that interesting. As you can see from the Tentacle Torque Calculator below we're going to run the whole setup at 13.2V, or 4S in LiFePO4 terms.
This is the worrying aspect of the design - how close we are on weight! Truthfully we guessed at the weight of the two polycabonate pulleys and the belt, so hopefully we've over-estimated. The only place we can save weight is by switching the baseplate from 6061 aluminium to polycarbonate, but that'll be a last resort move!
Here you can see the final effect - that's a 36" titanium blade, and the base is roughly 12" by 12" - it remains to be seen whether that's sufficient footprint for the 'bot to remain stable with that blade running at roughly 1500 rpm.
And lastly some team colours. This is the first asymmetric 'bot we've ever designed (with the weapon motor off to one side, but hopefully we've counter-balanced the weight okay with the batteries diagonally opposite. Win or lose, if that blade spins up, it'll be a treat to see! :-)
Tags: beetleweight, design, ll1
A few weeks ago, the first ever Kickstarter project we backed was successfully (over-)funded, and we're now waiting in anticipation of a Hexy the Hexapod kit. It comes with an acrylic chassis, eighteen metal-geared servos, and a controller on board. After thinking a while on the specs of the kit (18" across, 5" tall, weighs a bit over two pounds), we began to realize that we ought to be able to convert this kit into a Beetle!
As a walker, we'll be allowed six pounds to work with, so assuming the density of acrylic to be roughly a third that of aluminium, and guessing that a third of the kit is the chassis, an all-aluminium chassis would be about two pounds.
There are eighteen servos onboard, each one weighing 13 grams, or about half an ounce, for a total of nine ounces of servos. These servos evidently produce 2.2kg/cm of torque, and they can ably move the kit (2.2lb) plus an additional 0.8lb, i.e. these servos can move 3lb. In order to move a six pound 'bot we would need to find servos that are capable of producing 4.4kg/cm of torque, something like these, although they'll be a pricey upgrade.
Finally, we'll drop the head sensor from the 'bot, and mount an over-head hammer on the top plate, in the style of Mangi:
The 'bot may get chewed up and spat out in it's first match, but it's going to be fun learning how to interface a receiver with the Arduino-based controller, and it'll be a good learning step on the way to building a 60-pound walker Sportsman for the following year!
Tags: design, beetleweight, Hex1
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
This site contains records of our trials and tribulations in building combat robots. So much to learn, and so little time!