360 - mini hypnodisc

[mattsdragons]

Can anyone explain the theory being snail cams too me? Look very interesting and think I have worked it out but want some clarification

Build looks amazing though as usual from robochallenge

[Mouldy]

Try asking on an appropriate thread?

[mattsdragons]

Oops hahaha! Sorry dave

[Flag Captured]

Woah, is that really Beta? That's pretty cool if it is!
Have you got any structural updates planned for 720 as well with the drum being more powerful now? Just wondering from the fact that the drum's a bit heavier now and I seem to remember you mentioning on here that it'd spin faster (apologies if I've got my facts wrong!), didn't know if it'd require any alterations to accommodate that or anything?

Only curious is all, and for learning for my own designs in the future... maybe I'm a tad too nosy when it comes to other people's robots!

[Mouldy]

Nah no structural improvements needed- its allready super strong... only thing i've done is mill a pocket in the back plate, and change the drum axle to titanium, but that was just to get it in the weight limit. Also the drum is staying at the same speed- its allready the fastest spinning drum in the uk so no point going quicker

Jamie- you need to get drumroll back on form for next year mate... Guiltherm is making a new galactus also...i want that drum-off at the next champs :P

[RogueTwoRobots]

Jamie- you need to get drumroll back on form for next year mate... Guiltherm is making a new galactus also...i want that drum-off at the next champs :P

Will do my best. Needs a new chassis so that will let me start from the ground up. Not gonna go too OTT with the power as I'm happy enough with its offensive capability, focusing on reliability instead. Just want it to still be working long enough to have the drum-off

[Mega Masher]

LOL I'm so gullible

[evristow]

Touro Feather Manilla com SnailDrum.JPGCatching up from page 81! (took me a while to figure out when was my last message...)

4.3Kg at 15.6k is crazy! I am surprised it even engages at that speed, but that issue is answered by the next part. I wondered how long it would take a team to turn to the snail and mushroom shapes (Its been done before I know but not as far as I am aware in a drum bot) It must have been difficult getting those kinds of shapes in that length out of a single block of metal without a series CNC machine.

It did engage at the 15K RPM range, but the most powerful blows were in the 10~12K range.

Riobotz tested the snail concept, but a minor design mistake made the first version worst than the previous 304 stainless drum + dovetail S7 tooth. They also machined a mushroom drum for Touro (middleweight) that provided quite more bite. Both were done on a 4 axis CNC mill from solid 4340 round stock.

I, and I dare say everyone else, is very keen to see the inside of the new machine. The weight distribution must be very finely balanced to be able to get such a well armoured machine with such a potent weapon.

I might go to RioBotz's lab tomorrow, if so I can take some pictures. Anyway I do have a render, see attached.

Touro Feather Manilla com SnailDrum.JPG

Weight distribution is indeed critical, but the layout is pretty much standard.

Though even with the single tooth designs I wonder if it would be to your benefit to try the drum at maybe 2/3rds speed to test the better engagement you would have, and thus more energy transferred. It might make it even better!

Indeed that showed to be true.

EDIT: What is the Rotational Moment of Inertia for the weapon in CAD? I have been compiling a list of different weapons RMI, their shape and speed so that they can be put in some kind of order. All the numbers are relative but it means you can compare one design to another. I just wonder where Touro Feather fits in.

Got the numbers from Solidworks.

Standard drum* - mass: 3963g - MOI: 3326864 g/mm²
Snail drum - mass: 3950g - MOI: 3441789 g/mm²

*304 Stainless steel with single dovetail S7 tooth and tungsten counterweight.

Yeah i saw that robogames has gone... such a shame... and yeah going to rio would be awesome lol id love to come over there at some point depending on costs and persuading someone else to go with...do you live far from the venue? if not id probably ship 720 to you...

Not too far on Brazilian scale, 6 hours driving, it is a continental country after all. But if there are just two or three people we could take a ride on RioBotz bus - way more fun.

The problem is shipping anything to Brazil, our customs are unreliable and slow as a crippled turtle. Definitely not recommended. Also passengers flying to and from Brazil are entitled to 2 70lbs bags plus carry on, hence it is cheaper, faster and safer to bring it with you.

Anyway, or next big event (2014 Winter Challenge) will be next June or August. The date is not 100% defined because we don't want to conflict with the World Cup. You, as everyone else, are more then welcome to join us.

Also there will probably be an event in Miami, early May, usinf the BBIQ arena. Have you heard anything about it?

Allthough i think team riobots should sign up for next years uk champs and come get some real competition! lol

I am working on that

i've put in some time machining the new Hardox 500 teeth

How does Hardox 500 compare to P20 or S7 tool steel on this function? Just curious. Creusabro 8000 might be a good alternative

Also, i'm changing the drum axle for more grade 5 ti...

Good!

Poped over to grants and had a play with CAD and a 3D printer... made some prototype new front skids from ABS complete with "720" logo;

It does looks nice! But will the printed ABS be able to cope with the normal force generated during impact? Touro (mw) broke few "feet" due to fatigue.

Cheers,

Ed

[Mouldy]

doesnt seem as hard as p20- not sure about s7, but in both its definatly harder wearing, can take huge impacts and it'll just burr over slightly, where p20 and s7 seems to crack. Its also more then hard enough to damage most robots out there... but as its not a cutting weapon, it doesnt matter if it blunts slightly... but id hate to have a tooth snap off.

and the ABS was suprisingly strong.

Anyhow... just noticed i havnt really looked at 720 since october and the champs are slowly creeping up on me, been very busy over the last 12 months with buying a house, renovating it, building a track car and working silly hours at work... so totally forgotten about the robot... all ive had chance to do really is make some new stainless anti wedge feet for the front;





they run crazy close to the floor with all the weight of the drum directly above them, cant even get a piece of paper under the fronts there that low. I made 2 sets, one for everyone else, and a special set just for beauty ...Against pushy bots ill probably just stick with the nylon front skids though.

unfortunatly this put 720 over weight... so ive got to make a new top pannel from TI... which hopefully ill get around to next weekend, then i plan on going to the robotslive event in march to give it a shake down before a strip down for paint and loctite in time for the champs

[Flag Captured]

To be honest, I think everyone was hoping that you'd forget about it a little bit longer and not make it any more dangerous before the champs! Those anti-wedge skids, however nicely machined they are, are definitely going to be a pain for most people, including myself...

Quick question too, how big is 720, dimensions-wise? Whenever I see it on videos at the various championships, it looks rather small but for some reason looks a lot larger whenever you post photos of it on here!