glad you say that! if 6mm was good, then 10 will make it even better.
Just seen a couple of clips on youtube - NST vs Explosion, and it did take quite a beating :? but then its
'' just 5-6mm! ''
Printable View
glad you say that! if 6mm was good, then 10 will make it even better.
Just seen a couple of clips on youtube - NST vs Explosion, and it did take quite a beating :? but then its
'' just 5-6mm! ''
explosion does have a hardox frame underneath the hdpe though.
This is now a really solid machine, it's a brilliant evolution of Tormenta. Like I've said before with the amount of effort your putting in, Lipos are a must! Even if we have to have a whip round :)
10mm is sufficient for a single blow. NST could not cut all the way through my HDPE in one go but you need to be careful. If you are against Inertia XL or our spinners then we will get though 10mm of HDPE in a few hits. I know I have tried. I would have spares on hand to swap out just in case.
I reckon that our new machine might even be able to cut clean through Titanium and Hardox if we catch it at the right angle.
tormenta looks SOLID.
the weapon is very well built.
good job
5-6mm HDPE isn't strong enough on it's own, as said it does have a 3mm Hardox baseplate, flipper and a frame to support all of the HDPE panels, and a lot of screws! It's this that gives the robot it's strength, but even so, 14 hits from NST (which shows it's pretty tough) did tear up the frame, and so with it the HDPE. The frame had to be re-made in parts and all-new HDPE panels had to be made for Burgess hill. BUT, it still did completely protect the internals, and could have carried on if the link didn't come out.Quote:
Originally Posted by Relentless
As for your case, although the rest of the robot looks very strong, HDPE will not stand up very well on it's own if it's 'sticking out' (i.e at a corner for a spinner to get a good hit on) without anything supporting it. The most important thing to do is to make sure you fasten it very securely and strongly to the chassis because it is good for absorbing impacts, but only if it's rigid. It seems as if this was the issue with your last design, the sides were too flimsy. The best thing to do would be to make four small wheel pods out of something stronger such as Hardox, or titanium if you're tight on weight.
HOWEVER, what you have done so far looks very good and a massive improvement to the last one. :) As for the subject of lipos, we prefer to avoid them, as the weigh much more once put in a meal box and you have to mess about taking them out of the robot to charge them. If you are tight on weight, I'd recommend A123's, as there aren't so many safety precautions and are still quite light and still give a very high performance. We've used them in Annihilation and Eruption and have been very impressed.
Thanks all! And thanks for the constructive comment Mr. Invade! ^
Armour and battery upgrades aren't possible before MMM at the end of this month, because of the combined time and money both would take. I'm not sure, but I don't think there will be as many big hitters there as you'd expect at the UK champs. So, we'll make the thing as solid as possible for this event (and the following Maidstone event) and assuming it's still a usable machine afterwards, we'll look into upgrades.
I am thinking 2mm titanium would be possible as is, for the scoop and sides. If we were to lighten 'er up with new batteries and some other techniques, perhaps thicker. It then becomes a matter of being able to cut it and pay for it. All in mind for the future. If we go all out on this one straight after the mentioned events, the potential for a third robot for 2013 is diminished.
I will also look into A123s. These NiMHs should be powerful enough at 70a continuous discharge (only if every motor were stalled would we be exceeding that I think) for a while. I do know you can get A123s here with relative ease. Guilherme uses them. I'll have a chat with him!
What's the deal with charging A123s? We have a Turnigy Accucel 6, I have read that you charge them in LiFe-mode?
Thanks all! I'm going to go and look at how to mount the side armour more solidly. :P
A123 cells are Lithium-Iron-Phosphate chemical name LiFePO4, not to be confused with Li-Po (Lithium Polymer) or Li-Ion (Lithium Ion).
A123 cells don't have the same power/weight ratio as Li-Po (Li-Po wins that one, which is what makes it great for the smaller classes!) but they still output loads of power. Unfortunately iron is heavy.
And there's nothing in the rules that says you need a metal box for Li-Po.
just a minimum metal base of 2mm i believe
The metal baseplate for LiPo is not in the current rules. It's a proposal.
Made some good progress whilst waiting for the Botbitz to turn up. The top plate has been mostly made, it will need some slotting at the front yet. We also have made up the chocks on which the side armour will be mounted. These way just 200grams together, due to drilling 38mm holes in them. :lol:
We did that because we realised how close we are on weight. We're going to continue building with weight semi-on-the-mind until completion, and if we end up overweight (think we will) then we'll replace the top lifter bars with ali ones, as the current weigh 3/4kg!
Oh and the HDPE pipe has been attached to the back.
Coming along very nicely. It's doing what Tormenta did, looked the same for months and suddenly in the last two weeks its look changes wildly.
On photobucket you can see some of our PRECISION engineering, including a coat hanger clamped to the workbench which hangs over the already made hole in the machine, the technique being to slide the top plate into position and voil¡! Instant hole alignment. :proud:
Oh and also you can see how we drilled the top plate mounting holes into the bulkheads, by putting the robot on a sheet of HDPE and a briefcase, then putting the pillar drill on an old painting.
We're totally at the forefront of precision robot combat. :lol: - that said, the pic of our bulkheads is pretty cool. Each hole has a purpose!
http://s1088.photobucket.com/albums/i32 ... menta 2/
It looks excellent, well done!
Neat idea with the coat hanger! I'll have to nick that.
Side armour is now on! Thing is really sturdy, and I am warming to the shape. It isn't very flattering from the side but from above it looks pretty cool, if I may say so!
http://s1088.photobucket.com/albums/i32 ... menta 2/
Not much else to report, just some blurry pictures.
We sat it next to what remains of Tormenta for the sake of it. It's strange, when we built Tormenta it felt like were were at the limit of our tools and to an extent, skills. With a bit more experience (same tools, mind), Tormenta 2 at least looks a world away. This far in and we still don't know how reliable it all is, though. Structurally, we think so. Electronically, couldn't tell ya. The ESCheap85s still haven't shown themselves.
Right, 1:25am, bed I think!
its a boat! its a tank! its, its... pretty awesome man :)
I like the side on shot, makes it look like a tank or one of those beach landing craft with the front door down. What's the weight at the moment? Will you get it all in?
As it is in the pictures + batteries, it's about 1.5lbs under. Still needs some scoopy-business at the front, 3 ESCs and a load of wiring.
Going to be tight. We're pretty much set on changing the top bars to angle ali, which should free up a few hundred grams.
Thanks for the responses.
Edit: dad just came back from the post office with the speedos! Hoorah!
They're tiny. :o
lbs? what is this strange collection of letters? :lol:
I would make spare Ali beams as they will be much more easily bent than the steel ones in combat
Its going to be difficult to fight, from our perspective anyway, as there isn't an easy way to disable the machine with a disc (unless its OOTAs) as you can get up from any angle, and your wheels are reasonably well defended
Haha, lbs = pounds. Don't know why I went American on you there but seems I did. :?
We have tested the Botbits ESCs and both appear to be working as they should. The BEC is fine with the mixer and they failsafe. No bodge-wire-test-drive fun tonight though, perhaps tomorrow night. We have more or less settled on positions for the speedos, not what I had intended/expected, but should work.
Unless we buy 2m of ali we won't have enough for spares. Each arm is 40cm long. They should be fine for these two events, 90% of the stresses on them aren't side to side (bend-ways). We may not even have to go that route. The weight may be okay.
Only time will tell!
Got a 1:15am test drive, and yep, it's cool. The control is (as others have reported) not great down low but in the mid ranges it's very good. The ability to react is much better now, without the relays, too. Need to get some in-fury driving in to get a real feel but the signs are it's pretty beastly. At some 13kg it still wheel spins a lot!
The wiring has come along very nicely. All that is left is to figure out our link, and fit an LED. All three ESCs can be disconnected with deans, so it should be simple to repair if any wiring goes funky.
It isn't really an issue when driving (I don't think anyway, the in-fury tests will show), but the joystick fully into a corner somehow results in no movement at all. Anyone know what is causing that, and if it's easily resolved?
Hopefully get a vid up tomorrow! Thanks. :)
I'll just leave this here, then!
http://www.youtube.com/watch?v=MIAmOv_xx2o
That is very special indeed! Well done team! It looks and drives very solidily. Those botbitz give a nice control as well. So what's next top armour? Where will you be fighting it?
You didn't fancy lifting the sofa then! The control looks good with the botbitz and your machine looks very solid.
Thanks guys. :)
The top plate has already been made, we just left it off for this test because we don't have a link yet. Our only way of killing power is via the battery deans, and we wanted access just in case, you know, things got interesting. :wink:
We will be competing at MMM14 in Germany at the end of this month and we'll be popping in for a rumble or two at Maidstone.
As for the sofa, the sprocket on the lifter gearbox is slipping a little and we want to avoid making that any worse, plus it wouldn't lift the sofa, it would just lift it's own back end. :P
Broke two drill bits and spent about an hour in the meantime trying to put a hole through the thing to stop it from slipping. Managed it eventually. It was completely ridiculous! Ended up coming in at 2am. :?
We did get the link done, though.
Weighed it all-in so far, and according to our unknown-accuracy bathroom scales we have 200 grams left to do the scoopy-forky-thing. Not enough.
Hmm.
Been following this and I must say I'm very Impressed.
Looking forward to seeing it in action !!
John
Roaming Robots
Very nice, Rukia and Tormenta 2 need to have a fight to see who got the better lifter and believe me, she not going down easily :proud:
Thanks John!
Lewis, I love the idea of a duel. However, a duel might not be possible if we can't fix the pretty catastrophic failure we just had...
The cotter-pin system for the lifter-motor-side sprocket has been a pain in the behind for a day or two. Tonight we got a cotter in and it all looked good (having completely sheered the previous one; the torque in this big drill is other-worldly) so we stuck the Tormenta 1 remains on the front and gave it a lift. After a few bashes there was a snap.
The reverse thread screw that goes into the drill shaft (essential to the setup) has completely sheered where we cotter-pinned it.
We're working on a potential solution, but let me remind you that we are leaving on Monday morning for Germany. We have more or less everything involved before a 3 week roadtrip to do before we leave.
If we can't do it, we may have to call Germany or maybe even the whole trip off. No point in travelling 1600 miles to Dortmund to fight a weaponless robot. :?
I'll keep this updated.
Why don't you attach the gear onto the shaft like you would a blue wheel? Just tap the bore with the correct thread then lock it on with a reverse screw?
Loctite 601 :)
Well there is a slight issue in that the boss of the sprocket is the same diameter as the shaft on the drill.
(already been round that loop and came to what we have been using until now as the solution. I had no idea the motor could twist bolts in half, that's insane!)
Edit: and even if the boss were big enough, we have no reverse thread screws of the right size and type. Everything on this motor is 2x bigger than a standard drill motor.
Now leave in 3 days. Argh!
If the bolt sheering is the only issue then use a high tensile bolt instead, a bolt that doesn't have a thread all the way to the head. The threading creates a weakness.
Like this:
http://www.tool-net.co.uk/data/tools/13016htbobz.jpg
I know a lot of people who have to attach sprockets to shafts (chain driven HWs, FW spinning weapons) will put a pin through sprocket and shaft and then weld it in place. Just a tack on the end and where the pin sits.
Theres a potential lesson here that we've all been through before and I see it time and time again...
If you cant drop your robot off a table or throw it accross a room with confidence it cant take it, then normally its not strong enough.
Watching your videos of testing the lifter, you are very gentle with it... when in reality in a battle you are not going to be gentle, im not sure if it has mimit switches fitted now, but if it hasnt its going to get some grief in the arena when your being flipped all over the place !
Always plan for the unexpected, and a robot is only ever as strang as its weakest component.
I hope you get it sorted and keep us updated with progress, as i think its a cool little robot and im looking forward to seeing how it does in battle!
John
http://www.RoamingRobots.co.uk
Yeah, solid advice, John, and we have been much more rough with it off camera. We broke it in starting to more heavily test it, so I suppose better in testing than in the arena after travelling thousands of miles!
PJ, we're thinking of drilling out the threads on the drill shaft as we'll never get the right bolt again, or certainly not for use in this machine (would break in the same way). Remember it's a weirdly sized reverse thread bolt, which we can't find anyway, let alone a high tensile version. And certainly not within 3 days along with everything else.
We're going to drill the threads out and stick a 6.5mm steel tent peg in there and bodge something up. We don't have time for anything more clever. As for welding, it's on a minuscule scale and we can't weld with any confidence anyway. We risk wasting time and/or ruining the tiny sprocket. We could *potentially* find someone to weld it for us, but again, with a day or two to do so... meh.
We'll work something out by the end of today and hopefully by tonight we'll know if we'll be able to fix it in time.
Have you got a picture of the current setup and what broke?
Will take one in a bit, we're about to nip down to the post office to use their scales. Fingers crossed our bathroom scales are good and it's not actually 15kg or something!
Edit: not all bad news hoorah! Weighed in at 13.125kg. Our scales reckoned 13.4, so definitely a result! If we're clever with it, 4-500grams that should be enough.
I'm confused as to how it's currently held on, pictures please!
Are you just sliding the boss over the gearbox shaft thread, and then using the reverse thread screw to hold a washer against it?
If you want a quick fix I'd drill down through the boss and shaft (when in situ) as big as you can, and then drop through a bolt (same size as the hole). That way it's pinned in place laterally and radially. (It's not going to fall off or turn)
If you have the time/tools, I'd use a high tensile bolt, thread lock on the other end of the nut and tack weld points.
If you can't do that, take lots of bolts with you!
The sprocket can't be put around the drill shaft. The boss of the sprocket is literally the same size as the drill shaft. Physically impossible to put the sprocket over it!
The sprocket has a bore the same size as the reverse screw. We clamped it between the shaft (with the nut pulled from the chuck) and the reverse thread bolt. Really tight. With loctite. We then cotter-pinned the nut, shaft, and bolt (not sprocket) so that they couldn't loosen. The sprocket had a setscrew which went onto the bolt. It was seriously solid.
That worked well for a while, but as the setscrew loosened a little the reverse bolt got mashed (the sprocket could turn with the torque despite being compressed to hell between the bolt and the shaft as well), and so it didn't grip. We decided to cotter the sprocket through the bolt too. This worked well, until our first pin sheared completely. Out second stronger pin should have been the final fix, but after lifting about 6kg of Tormenta 1 the reverse thread bolt twisted and broke in two. We have strengthened parts and so moved the weak point from the setscrew, to the cotter pin, to the bolt.
That is where we are at now. I'll try and get a pic together but it's in pieces now! This is a very old picture but you can sort of see it here: http://s1088.photobucket.com/albums/i32 ... 012433.jpg
I think your problem is the locking bolt diameter is too small, it's length too long and the material weak, specially if it's got no plain shank on the bolt.
I would drill the motor shaft and sprocket to a larger diameter, then tap a new thread to the motor shaft and use a proper bolt as already mentioned, high tensile or similar.
If you were not so much pressed with time I'd have sent you a couple of titanium bolts, it would be difficult to damage those :wink:
A bolt isn't the way to go, really. By their nature they aren't as strong as solid rod, and the ability to tighten and twist isn't necessarily useful. Plus (as I have said), we'd need a reverse thread tap and a matching reverse thread screw. For us, at least, that's really out of the question, and more so before Monday.
Well we fixed it. For a while. We drilled out the drill shaft threads and hammer-fitted a 6.5mm thick solid steel rod. We made a fresh cotter-pin going through the chuck nut, the drill shaft and the rod. Very solid. We then also hammer-fitted the sprocket into place and cotter-pinned that and the rod. Took us two rod attempts, and two broken drill bits (they're cheap bits, admittedly, but that rod is seriously tough stuff. We believe its original function was to be a big tent-peg). Put it all back together, put Tormenta 1's remains on it, and all looked perfect for a minute or two after some rough use. Then, snap.
The thing has snapped the steel rod too. It's crazy. We have built something we can't handle.
At this point we're so stuck for time that we may have to bash out another peg, build it just as we did, and put the torque limiter down. At least we'd have a robot that won't destroy itself. It may well be unable to lift anything much heavier than itself, though.
This is pretty disastrous, really. We never predicted this to be the weak point. Mike, if you read this, man I didn't believe you when you said you were snapping shafts but by-God, I do now!
Show is over for tonight folks, bedtime now.