Imagine a flexible tube, arranged so that it travels through itself and each free end is joined together.
Such a tube can move in a strange way: the inner tube can move to one end and become the outer tube, and at the other end the outer tube becomes the inner tube.

If a system is employed to drive the inner tube in one direction with respect to the outer tube, then the complete arrangement will be able to move across the terrain. Drive wheels could do this, in discrete locations around the circumference, between the inner and outer tubes. This would allow differential drive speeds and steering.
Furthermore, if the tube was long enough, it could surmount large obstacles.

I tried to think of a pneumatically operated drive system, but failed. Maybe someone else has a better idea for the drive system?
-- Ling, Jan 04 2005

Sodaplaycentral http://www.sodaplaycentral.com/index.php
SW3D can be found here, as well as info on SodaConstructor [5th Earth, Jan 04 2005]

Drive system http://www.newscien...rticle.ns?id=dn6095
Drive system [brodie, Jan 04 2005]

If I understand this correctly, It seems to me that the best application might be a Mars rover if it is big and heavy enough with sensing equiptment in the middle.

Is the main purpose to traverse complicated 3d terrain?
-- Zimmy, Jan 04 2005


[Zimmy], It could have many purposes, one of which is the ability to traverse complicated terrain, but it need not be heavy (full of air). Getting sensors to probe outside might be more difficult.
It could move in water since the surface area of the outer tube is greater than the surface area of the inner tube.
-- Ling, Jan 04 2005


Sort of baked, in a highly abstract way. There's an obscure program called "Springs World 3D", which is a 3D version of another (2D) program called Sodaplay, and in SW3D there is a creature-design-thing that functions this way. SodaConstructor also has a 2D version of this idea, but it's less interesting.
-- 5th Earth, Jan 04 2005


My daughter has a fluid-filled toy version of this; interestingly it demonstrates the same principles, albeit without the 'drive' mechanism. My one problematic observation is that as the tube moves, the 'outside' becomes the 'inside'. The naturally more compact inside would rapidly become clogged with ground matter like dirt, mud, etc.
-- xrayTed, Jan 04 2005


Kinda like one big wacky weiner thingy. How is this a robot, though?

Not sure if it's the same or not, but seems to me Steve did a transportation device based on a similar concept once, only it was bowl shaped.
-- waugsqueke, Jan 04 2005


[Ling], a suggested market application: Mini Waxing Tubots. Wax is heated internally and laid down as the tube everts, cools as the tubot moves forward and is collected, with hair and follicle tissue, at the rear. Let a handful of the programmed little beggars go in the salon. "Todays Special - Hands Off Brazilian - $15."
-- ConsulFlaminicus, Jan 04 2005


here's your drive system (see link).
-- brodie, Jan 04 2005


You could drive this with rings in the skin, contracting at the front and expanding at the rear. I think getting this thing to turn, and to flow when it has a kink in it, might be difficult.
-- tiromancer, Jan 04 2005


Yeah, it's hardly a robot; I like the name, but category choice is difficult.
[brodie], I saw the memory alloy propelled wheel in another idea, and my mind wandered around until the Tubot came out. If the tube was made from memory alloy, could it be made to "evert" (thanks, CF)?
I like [tiromancer]'s line of thought. I had some idea which involved the sqeezing of the tube at one end, and the air pressure made the other end evert, but what could squeeze the end continuously? Think about the power system and wiring or whatever. Would the drive system need to be fixed, or could it also flow with the tube?
[CF] self propelled dildos?
-- Ling, Jan 05 2005


I can see a tank inside a tire's low pressure rubber tube having good traction.
-- mensmaximus, Jan 05 2005


If the rings were made from SMAs, you would just need to float a heater (or a stack of peltiers) inside. I suppose that could also work with freon or something like it.

I remember an article about artificial muscles which contract when light is pumped through them, so that could work.

Another option would be to build a kind of linear motor and everything else(electromagnets, control, communication,sensors) into the skin. The tube could be filled with hydrogen, and power generated by fuel cells in the skin.
-- tiromancer, Jan 05 2005


An alternative drive system is to pneumatically inflate and deflate sections of the skin sequentially.
-- mensmaximus, Jan 05 2005



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