Tashic's Robots

[Tashic]

Sketcht this yesterday, what do you think of it?
Cattura.JPGCattura2.JPGCattura3.JPG
this is not definitive, but I want to keep the basic shape.
I will use small wheels because the axe is supposed to self right the robot.
I will put he axe later.

[Eventorizon]

Damn, that thing is built like a brick! The design looks good, you will want to cover up the weapon motor with something though. I am not sure the axe will have enough power to right the robot given the geometry but if it doesn't you can gear it down a little further. What is the weight given its insane structure?

Aside from that, looks cool, looks original... build it!

[mrsam]

What type of motor is it? And also what reduction and voltage do you plan on running

[Tashic]

The motor is this:http://www.ebay.it/itm/Electric-Moto...item2596f1dfe1,

the voltage is going to be 14.4V and I plan to use a 5:1 reduction.

Also Alex,do you think I should simplify it?
I will try to make it wider and shorter, that should help self right a bit.

[mrsam]

Same motor I ran for my axe this year, I'd recommend a higher voltage though just so you're not undervolting it too much.

[Eventorizon]

If he goes higher on the weapon he may damage the drive. Its the same issue you would have had. Split voltage is always an option but that means 2 links and more complex wiring.

As a rule of thumb your robots wheel base should be wider than it is longer as it helps turning and reduces scrubbing, square at maximum. If you can do that then go for it.

The robot looks fairly simple, just very sturdily built. You may have issues getting your drive motors in and out but its just inherent in the design.

[Flag Captured]

To be honest, I'd go for two batteries in this case, I feel like undervolting the axe motor that far would end up being quite a hindrance as far as power output goes. Yes it does mean two links, but stick a small 24v battery in there and I doubt it would add too much in the way of complication, and you'd get an awful lot of gain - could even adjust your ratio a little too to reduce the strain on the motor and get a little more torque out of the axe itself (excellent for self righting)

As far as the design goes though, I really like that - it seems rather solid and certainly something different! What materials are you planning to use for the build?

[Tashic]

The materials are still not decided, but it's between HDPE and polycarb, 20 mm.
I would use HDPE, but it is damn difficult to find in Italy, the only company that sells that stuff is in Turin (north of italy), while I live in Sardinia.
So if I can't find a solution I will have to use polycarb, since I can buy it close to home.
It will be more fragile but much cooler!
Plus front, sides,bottom and axe are going to be made of steel.

[Flag Captured]

As cool as polycarb is... I'm not sure I'd recommend using it for something like this - top panel could work but structural parts, HDPE outshines it massively from what I've seen personally... Steel for all those parts is definitely a good idea though. Get the angles right around the sides and it'll take very little damage from spinners!

I'd really recommend HDPE over Polycarbonate - Hatchet's baseplate was in quite a state after Mr Mangle hit it, cracked straight through... you could get some polycarb as armour easily but I think the trick is to leave it a little free so it has room to flex (like the arena walls have) so wouldn't be too useful for your structural components which would have to be quite tightly bolted. You can buy it quite readily online though, if that proves a useful option!

[Eventorizon]

Use HDPE if you can. Polycarbonate is only good for one hit, after that its properties change and it becomes brittle.

[Flag Captured]

https://www.youtube.com/watch?v=w53VoBPa844

http://s1355.photobucket.com/user/Th...37810.jpg.html

Very brittle indeed. I do recall Sam changed it to HDPE after that, and had no problems afterwards with the strength... so take that how you will!

[Eventorizon]

The base of Hatchet is now 10mm HDPE rather than 10mm Polycarb. Its been clobbered by so many robots, even direct hits from Battleaxe, and its still fine. Go with HDPE.

[Ellis]

On the other hand if you won't be fighting in full combat events with this then polycarb will be fine. And you can make spares for bits likely to suffer if it's cheap and sourced close to home. Polycarb shatters, but only in high speed impacts.

[Flag Captured]

I went on the assumption it was a spinner-proof design! Yeah, non-spinner events should put up with polycarbonate well enough and if you can get replacements easily it may be cheaper. What's the weight density like of Polycarb and HDPE, are they around the same?

Because if so, it's always possible you could build with what's to hand and then remake the same parts in HDPE in the future if you choose to go to a full combat event, that's possible I suppose!

[Ellis]

HDPE is lighter so that works out well. About 0.95g/cm3, vs polycarb's 1.21g/cm3.