Tormenta 2 - Build Diary

Thanks!

Well after a day's worth of sore fingers and grease going in all directions, the new motors and gearboxes are in. There were some complications in mounting them, so it took much longer than I expected, but it's all looking pretty healthy. I'll stick the some pictures up of the

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Originally Posted by Ellis

make-a-massive-mess-on-the-dining-table-fest-2013

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tomorrow, which was as satisfyingly massive as I had predicted.

I couldn't drive it at any speed this evening due to noise (by this evening I mean 12am...) but creeping around it feels a world better than it did before. It's a lot smoother and the low-end finesse has doubled. From what I can feel it has lost *some* mad explosiveness but, in the single full burst I did, it still had enough power to wheelspin, which is awesome. I'll be able to drive it with a bit more confidence tomorrow, and hopefully I'll confirm my current opinion, which is that the parts were money very well spent. :)

Bed time I think.

Whats uour current set up ellis? From the looks of things there is tons of power in there

Until last night, 12v drills at either 18v NiMHs or 5s LiPo, 36:1 and 100mm wheels. The same tons of power that allowed us to plow through machines in the hockey game at MMM was the same power that made it so unreliable. :(

I have yet to test the new setup (18v motors and 24:1 ratios) in anger but I have a feeling it's still got plenty of push.

edit: oh and the pictures of the

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Originally Posted by Ellis

make-a-massive-mess-on-the-dining-table-fest-2013

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as promised...
http://i1088.photobucket.com/albums/...g?t=1363692714
http://i1088.photobucket.com/albums/...g?t=1363692746
http://i1088.photobucket.com/albums/...g?t=1363692733
http://i1088.photobucket.com/albums/...g?t=1363692720

Im doing the same changes as you, though my set up never broke, everything got hotter than it should so im.interested to see how you think the mods go

More driving suggests the mods are well worth it: should be more reliable, same speed, less heat, etc. ^

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We have made our own wheels. They work in exactly the same way as blue wheels, with the reverse thread screw locking against the wheel which locks onto the normal thread to hold the wheel on the shaft. The blue wheels sometimes worked their way loose but they were never an issue, they stayed tight 95% of the time. But despite cranking our own wheels down hard, harder than we ever had to before, they work their way loose. Everything is solid, in that it's metal on metal and it's essentially a replica of the blue wheels, but they still work loose.

The tread is just bike tyre, but it does seem to grip our dusty floor better than the blue wheels. The only thing that I can think of is that the added grip means that we're effectively putting more torque through the wheels, and that we've just reached the limit of the standard attachment method for drills? Does that tie in with other people's experiences? If we try tightening more we'll be entering thread stripping territory.

Any ideas? Any old hands got solutions to wheels loosening like this? Going to look into alternate attachment methods. Suddenly, though, we leave in 5 days. Eek!

Thanks.

We had the same issue with Hannibalito 4.

But that's permanently fixed with 2K glue. Removing a wheel asks for a hot air gun tough.

Ellis why don't you fix the wheel to the shaft in a way similar to the way a drill chuck is fixed to the shaft. I never had a wheel coming off this way. I'm using a metal hub threaded with the same thread as the shaft, the hub will cover the whole length of the thread on the shaft. Then the locking screw will lock everything in place. Its impossible to work loose this way as long as you dont strip the threads or shear off the lock screw

You could try Locite on both the main shaft and the counter-thread in the centre. Though I am still surprised that you are working loose an anti-clockwise bolt!

This is why I have opted for the banebots hex hubs with key ways this year. I lost that fight with beauty two years back because a wheel came loose. Shouldn't be an issue now

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Originally Posted by Liftoff

Ellis why don't you fix the wheel to the shaft in a way similar to the way a drill chuck is fixed to the shaft. I never had a wheel coming off this way. I'm using a metal hub threaded with the same thread as the shaft, the hub will cover the whole length of the thread on the shaft. Then the locking screw will lock everything in place. Its impossible to work loose this way as long as you dont strip the threads or shear off the lock screw

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That is precisely our setup and it works loose within about 20 seconds of driving hard...

It does feel like it shouldn't be possible but it certainly is, because it keeps happening!

We're going to try locking agents like loctite, see if they help.

And we're looking into alternatives, Gary, such as banebots hubs or in fact making our own. Hoping loctite of some sort does it, though, purely for simplicity.

Hmm interesting!! I find it mechanically impossible for this to happen without something breaking :shock:

would you mind posting a couple of pics of the wheels and shaft - you got me really intrigued by this...especially since I had similar problems before, which I solved using this setup.

Are you sure the head of the reverse screw is up against the face of the wheel? Sometimes it needs a few washers as there is a limit to how far you can screw in the screw. We have had problems before where we did the bolt up as hard as we could and the wheel would still unscrew, solved it with loctite and a large penny washer.

I am sure that it is all locked up, yes. More so than with the blue wheels, in fact. We never locked onto the wheel with those, but onto the face of the nut insert. We used washers (2) like this for the blue wheels, but they get seriously deformed and eventually are no good. We moved to just using m6 nuts, which work much better, but despite all of the friction the wheels still loosen.

I am beginning to think there is not enough friction between the shaft and the wheel, and too much between the wheel and the reverse thread screw. However if it were all locked properly nothing should loosen, so go figure! :P

Going to try loctite now.

Oh and I'll get some pics and video up if we manage to fix this.

I've had similar issues in the past. What you want to find is some reverse screws with a hex head to really tighten them up proper

its odd that it loosens so quickly? mine takes quiet a few battles to severely loosen, and to prevent this i have hole in the wheel guards so i can tighten the left handed screw. i have no idea why yours loosens so much though, got to be some hidden play somewhere.

Is the wheel made from plastic or metal at the part it threads onto the shaft?

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Originally Posted by typhoon_driver

I've had similar issues in the past. What you want to find is some reverse screws with a hex head to really tighten them up proper

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We're using the ones sold by RoboChallenge, allen key head, we can put enough twist on them to break them, so we can crank them properly.

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Originally Posted by Liftoff

Is the wheel made from plastic or metal at the part it threads onto the shaft?

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The wheel itself is plastic, like the blue wheels, nylon or similar, but no we have a long 3/8 nut insert onto the shaft.

We have loctited everything and we'll see how it fairs soon.

The loctite appears to have done the trick, at least for the minute, as the video below shows. Hoping it's a permanent solution, the alternative is to try and be clever with grub screws or something and if that's avoidable, great.

We decided to document the process of making these wheels in the hope that it might help someone...

Vid 1: http://www.youtube.com/watch?v=AcIIUGBJzJM
Vid 2: http://www.youtube.com/watch?v=vqf9i_er56Q

The above probably won't interest many of you, but part 3 has a test drive:

http://www.youtube.com/watch?v=XlddYVSIe7s

(armour is off because we may have further clearance issues, will look into it tomorrow)

Briefly forgetting the wheels and their undoing problem, this + indoor tests have been a pretty good shakedown for the new drive system. I won't say this has been one of the best improvements to the machine until we've stuck it in the arena, but even now I would recommend it to anyone who is overvolting to get some speed. The motors get warm at most, after a drive like the above before the motors would have been toasty.

Also, an added bonus of the wheels, they leave epic skid marks everywhere. :proud: (including the kitchen floor)

Thanks for the help.

Thanks for that, i may use that method in the future for my robot.
Good luck with the championships and hope you do well.

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Originally Posted by Ellis

Also, an added bonus of the wheels, they leave epic skid marks everywhere. :proud: (including the kitchen floor)

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As the rubber goes down over the weekend, we will see the cars going faster and faster. Only problem is if it rains the track surface will be come far slicker than it would otherwise.

Awesome, looks good! and a very similar manufacture method to what I would use... and i wouldn't mind wide wheels as wide as the, but I find the blue wheels have brilliant grip when treated and used well.

I have spent the past 2 days slowly putting this thing back together, analysing it as I go, and had it 95% ready and decided to drive it around a bit. Can't get enough practice and that.

I broke it. D:

Well, the rear right gearbox failed. Completely locked up. Managed to catch it before the motor burned out, so no issue there. The Gimson stuff also appears to be unharmed. It's our old friend the second stage pin that decided to come loose.

I'm a bit disheartened as I had finally got everything bolted back on, and minutes later I had to rip it all apart again, but having opened up the gearbox things could be a lot worse. Only a single pin failed, in the past all of them would fail in unison. And, the gearbox that went is the oldest we own, it's one of the two that Sam gave is at the '12 champs as a sorry for killing our robot (lol). It used to be in NST. I don't even know how long ago NST ran drills, but we have had it for a year (and used it overvolted, a lot) on top of that.

So, as just one pin gave way and it's an ancient gearbox I think we're still safe. It might well have been loose from the start. I have a replacement gearbox to put in. Don't know what we'll do if they continue to break...

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In other news we have made our battery box and have discovered we need an extra tensioner for the chain, which will have to be simple (leave in 3 days). In happy news, the wheels seem to be holding up very nicely.

how many spacers have you got in that gear box? as you've charged the reduction you would need 2 of the metal ones rather than one. as originally they had 2 spacers when they had the plastic first stage reduction, and then if you changed it to metal gears, you probably had to remove them. But when you changed it to 24:1 reduction, the gears are thinner so you need more spacers. The spacers should give the pins less room to fall out.

You don't need spacers in drill gearboxes, unless I'm not understanding something. If you mean the spacers thing mentioned on the Gimson website, that's unique to GR02s. In fact, you can't have them in drills, as it would force the shaft beyond the circlip and cause the whole system to fail.

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Originally Posted by Ellis

Of course, you don't need/can't place spacers in drill gearboxes. The groove cut for the circlip dictates the position of the shaft in and out, so it's fine. The gears tower up to the same height as the factory gears anyway, so we shouldn't have to do anything more advanced than replacing the gears and motor.

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What about the metal disks that are between the motor and first set of gears? mine came with two, and as you gearboxes looked identical, I presumed they were the same. I found that the pins came out if I was missing some. I don't know it yours are different though.

Ours have never come with two plates... that's odd. We once put two in accidentally (don't ask) and it didn't like it at all, but I'll look into that tomorrow. Thanks.

I think it's simply the mechanical limit of a pin pushed into a hole, then loads of lateral force being put on it. If over the past 3 years it has been used and used and used, every time the drill changes direction hard the pins come under stress. So if we're lucky this is simply fatigue and we won't see a repeat with the newer gearboxes.

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Also, oddly, one of the pinions on the 18v motors has come loose. Ewan has very kindly sent out a replacement, and we'll try to get the current one back together. I don't really have an explanation as to why it came loose, Ewan said he has never had a report of one loosening before, so I can only assume it was a dodgy one from purchase. Bit of a shame, as if we can't fix it we can't have any more test drives until we get to the UK and put in the new one, but it could be worse.

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Originally Posted by Ellis

I have a replacement gearbox to put in. Don't know what we'll do if they continue to break...

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Stock up on GR02 drill shafts and replace them instead of the gearboxes.

If you take the shaft circlip off and remove the ball bearings, you can stick a screwdriver in the end of the shaft (careful not to damage the reverse thread) and hammer it out through the gearbox housing with relative ease. Hammer a new one in its place, then refit the bearings and circlip.

Done this many times over the years and not had a problem. A much easier solution now that Ewan stocks the shafts. Managed to 'make' six 12V drill motors the other week from old empty gearboxes just by stocking up on the shafts and motors :)

This sounds like a problem that could be fixed with a tig welder... You got 4 sets of plates with pins that have fallen apart? If so bring them along to the champs, I'm sure if you ask grant nicely he'll weld them up on one of the nights.

Feels like we've got more than 4 sets! I'll bring them along. Might as well weld any good ones too, and just avoid the issue.

Also Jamie, I've replaced shafts in these a few times, I just avoid doing it if possible as it feels quite invasive, especially if I have an alternate complete gearbox available. For the future we're going to try and ditch the reverse thread screw locking method and go for some form of grubscrew setup, the GR02 shafts will be perfect for that, with their flats. Had already crossed my mind to do that ahead of the champs but I don't see why the pins on those shafts would be any stronger, I believe they're identical. One day we'll run out of old drill shafts, I'll go Gimson shafts then!

Crossing my fingers that the failure we had was because it was an abused gearbox, and not because we're still putting too much stress on the pins. Don't see how we can be, to be honest, we're no longer overvolting...

Reading this thread is not giving me any confidence in my Argos 12v drills....

If they haven't been used in a silly overvolted setup for a year then they should last perfectly well. Replace the plastic gears with metal ones, run them at their nominal voltage, and they should last years. We're just pushing their limits way beyond reason. :lol:

I seconds Ellis on that, as long as they are on all metal gears you can run them all day and not have a problem

Erm, yeh they're not :uhoh:

Can buy some metal gears from ewan, about 4 quid for a set of 3

Well even the plastic gears should last some time if you're not overvolting and running them hard (big wheels, powerful batteries, harsh driving, etc) but they will fail eventually. The resulting plastic mess will go all around your gearbox and get stuck in the grease, and the only way to ensure they run smoothly from then is to strip them completely (toothbrush + warm soapy water, in our experience). Any plastic bits left inside and it'll never run smoothly.

I'd save yourself the whole hassle of that and just buy some metal gears from Gimson. It's worth the money in time spent having to mess with the gearboxes once the nylon gears fail. Plus there's a chance that them failing will cause the gearbox to lock up, and you could burn a motor out... point is it starts costing money quickly!

The issue is that BitzaWood was never intended to be a long term machine, so changing parts is a pain.
I'm just hoping it'll last the weekend then I'll make a proper version after.

Thought you guys might be interested in this! Not long now!

http://www.youtube.com/watch?v=tWdrL43vF3k

Looking great Ellis, can't wait to see it at the weekend. And your journey, though longer, looks far more awesome :)

Been a while since I posted here.

Tormenta 2 is kind of in limbo. It's not quite dead enough to justify moving on completely, but it will take quite a lot of work to bring it back up to 100%.

We were killing gearboxes as regularly as ever up until the last day of Yeovil. There, after discussions at the pub the previous night, James/Grant/Nick donated some of their modified drill shafts that they made up to run in their kitbots. We did three fights after swapping them in at Yeovil and another four at Colchester without a failure. Looks like Tormenta 2's drive is finally getting there in reliability.

However after that happy note we got a direct hit from Major Damage at Colchester. The hammer hit the top bars square, and in doing so it has completely marmaladed (that's a word now) the threads that hold the sprocket adapter Mario made for us last year onto the weapon motor shaft. That will need to be completely rethought, as the threads on the drill are literally no longer there, and retapping makes no sense as it'll fail in the same way eventually.

Moving on to the inherent flaws of our design, the robot needs to be a lot tougher at the front. To make it tougher, we need to claw back some weight. I don't completely know how we'll do that yet, but by changing a few things I think we can get about a kg extra to play with. That shall go into a nice hardox plate on the front, and anything else that can be reinforced.

Another flaw is trying to use chain for ratio reduction as well as simple transmission. If it were 1:1 we could just up size the chain (it broke constantly at the champs and Yeovil, constantly...) but that isn't possible. So we're going to try a belt and pulleys. That ties in to what we do about the weapon motor shaft being mangled. I'm confident there's a way, though.

Otherwise it's basically alright. The pros and cons of the robot are more or less balanced, so our plan is to give it one last burst of life and let it run from there until it can't. We'll be taking it to Germany in September (to try and win this time!) and if it lives through that, we'll put it in for next year's champs.

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Tldr; Tormenta 2 is in a state but we're going to give it one more lease of life, despite it being in a bad way after the latest trip.

Well, that September trip never happened. Instead we went to the UK (just dad and I), more for family reasons, but as those who's hands we shook and who's bits of robot I used to make my beetle work will know, we got to the Deeside event with Gonzales. That's a different thread, though.
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I thought I had lost the fight footage of Tormenta 2 from Yeovil. It disappeared without trace for months, until a few weeks ago, when it was discovered on mum's PC... for... some reason. Either way, I just got around to uploading the fights.

You can see them near the top, here: http://www.youtube.com/user/TeamExpat/videos

Or, if preferred, the individual links, not necessarily in chronological order (can't make them links as it automatically makes them videos):
http://www.youtube.com/watch?v=f6CY-Fy2XA8
http://www.youtube.com/watch?v=Nro5Ii2J4SY
http://www.youtube.com/watch?v=PtIVjlbKWI0
http://www.youtube.com/watch?v=tDM6jMoEJyQ
http://www.youtube.com/watch?v=TcZCvt7BcNo
http://www.youtube.com/watch?v=g5oIwyhUqhU
http://www.youtube.com/watch?v=6Bor7DXCEB8
http://www.youtube.com/watch?v=Lu6Zdv4sv3Y

In robot terms this event was actually quite hard. Essentially every fight resulted in either a gearbox failing, or the chain breaking. Overall of course it was very relaxed, more people should go to the events held in Yeovil!

Anyway, I am very happy with some of the performances of the machine in the above fights. I think they're some of its strongest, which is odd, considering the robot got mauled just 3 days earlier at the champs. That scoop is some springsteel cement flattening whatsit from Wickes, properly bodged on. Yes, the enemies weren't super high end spinners, but still, this event showed us that the weapon concept works. Just thought I'd pop them up here as this is meant to be a diary for the thing. :P

These videos have refueled the want to get on and build Tormenta 3!