Berzerker - undercutting bar spinner - 2010

OK...a lot of hassle later, including a burglary :angry: - here goes the build thread! :) Sadly the brushless drumbot project got wrecked by having a toolbox holding most of the metal parts for the damn thing - including the very nicely machined drum done by Kenny (ALK Engineering) - stolen by some burglars. Thankfully insurance paid out - that and I feel better off at the moment - so it's time to go ahead! Here's the start of the build thread (requested by Dave):

http://img163.imageshack.us/img163/3...eberzerker.jpg

Basically - T shaped spinning bar undercutter powered by two brushless motors, swinging a bar up to 800mm long (the bar in the above CAD renders is 700mm). The weapon drive is by a 90 degree twisted timing belt - by rule of thumb the belt should be long enough not to jump, especially with wider pulleys and flanges.

The rest of the bot is pretty straightforward - a couple of rock crawler motors run through 16:1 planetary gearboxes to the wheels, which should move it about nicely, RC helicopter gyro to stabilise it against the spinup torque of the weapon, and a whole bunch of batteries; I'm leaning in the direction of a small lipo pack to run the drives with A123s on the weapon for the insane 70c burst current they can deliver (that, and they're a lot cheaper than the huge lipo packs I'd need to run the weapon).

Most of the chassis will be heat bent grade 5 Ti of various thicknesses; work on that will start after the New Year :)

Sorry to hear your drun and other parts were stolen - but this new design does sound pretty awesome :proud:
Good luck with it!

no way really sorry to hear that, after all that work on it and the drum aswell:(

but the new robot is lookin just as good:)

good luck with it

Just ordered a section of S7 tool steel bar stock which will become the weapon bar... :)

Should be nasty with 3 times the energy of 360 :(.. But why are you using S7? Its pretty soft.

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Originally Posted by mr_turbulence

Should be nasty with 3 times the energy of 360 :(.. But why are you using S7? Its pretty soft.

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Only going to harden to 54hrc, true... does the job though, far, far cheaper than more exotic steels. I'd rather get the thing working asap with a simple pocketed bar weapon, and upgrade later at some point with a Ti bar/Ali or Mg stiffener/counterweighted single tooth in a harder steel... but I can't be arsed to FEA impact analyse everything to see if it will work (especially as my software is crap) right before term starts again. :p: S7 just has such a high impact strength compared to a lot of steels that it's a lot easier to get away with.

Nick.....i am probably the most foul mouthed person you will ever meet but i do refrain from using bad language on this forum.

Can you please do the same.

Sorry mate, won't happen again :rofl:

Got the Ti and all (3mm and 6.25mm, grade 5) and will be getting the chassis heat bent on a press brake soonish...

Got a nice block of 7075 to be machined into the weapon mount also. Soon as I get some parts actually finished, oh yes there will be photos :)

OKAY, time to resurrect this! Finals rather took over my life this spring/summer, and I've been on holiday for a week afterwards, but now it's time to get down to actually building something :)

First lot of parts came off the waterjet today, so here goes a shot of the internal layout - brushless escs and a couple more little batteries excluded as those bolt to the sides of the frame (which STILL NEEDS TO BE WELDED UP :rofl: but that'll be done next week or so). You'll be able to see how this section all fits in if you take a peek at some of the renderings in my first post.

http://img294.imageshack.us/img294/1658/robot1004.jpg

Yeah, the gearboxes haven't been assembled and bolted down because I've lost my tin of grease and they'll have to come off anyway when putting the frame on...

Hmm, I wonder what's under that front strip? :twisted:
http://img94.imageshack.us/img94/9534/robot1005.jpg

After all, big spinning things need power... :rofl:

Oh, and here's the beginnings of a little 3lb robot - yeah, another spinner! It's going to have a little Scorpion motor running a horizontal blade off a timing belt drive, you'll probably be able to work out how it'll look pretty easily...

http://img193.imageshack.us/img193/6061/robot1001.jpg

http://img40.imageshack.us/img40/8659/robot1002.jpg

http://img708.imageshack.us/img708/3096/robot1003.jpg

Looking Really good! Welcome to the stupid world of overpowered brushless spinners lol Be interesting to see how bad the voltage sags on the a123's with the castle link software.

Nice to see that it's starting to come together, although the pic of your beetleweight chassis just made mine look like a pile of rubbish :P

Are you hoping to have this all up and running to compete at the UK champs? Or just taking it steadily and it will be built when it's built?

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Originally Posted by k_c_r

Nice to see that it's starting to come together, although the pic of your beetleweight chassis just made mine look like a pile of rubbish :P

Are you hoping to have this all up and running to compete at the UK champs? Or just taking it steadily and it will be built when it's built?

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Will be indeed running at the UK champs :)

Progress today - made + installed the drive motor mounts for the beetle out of some 10mm UHMW and hooked up the electrics, it's just about driving - or would be except I ordered 2 inch wheels instead of 2.5! Too small in other words, and get hung up on the bolt heads. I'm going to get some low profile cap screws and slightly bigger wheels - next step will be to mill out a timing pulley and press fit over the brushless motor can, as well as make the dead shaft for the weapon.

The feather - starting bending up the frame which I never DID get done due to the uni press brake being broken for the longest time and then finals coming up. An annoying job involving two big propane torches and many, many jigs. :(

Frame done, just needs cleaning up welds with the grinder and then paint.

http://img705.imageshack.us/img705/6...ameresized.jpg

Edit - in other news, made the longer shafts for the brushless motors, mounted the timing pulley to them, and made some progress with wiring the thing up. Put the armour on the 3lb, still needs that little bit of machine work on the pulleys and a weapon blade.

Looks really good mate. Hopefully it will be ready for a test drive soon by the looks of it :)

Driving, needs a bit more machine work to get the spinner done, but not entering UK champs anyway due to other issues... oh well.

I'm currently busy with a vaguely related project - custom field oriented sensored brushless controller :) got it mostly working on a development board to the point that the little brushless I'm using for testing is spinning away happily! Field oriented control code however isn't totally sorted, and more to the point the development board will only handle like 6A while the actual controllers need closer to 200A - we shall see how this goes.

Hopefully it'll mean no more controller worries though!