Let's Make Robots!

Tank tread vs 6 wheel drive vs WTF!, which is better?

I notice that most people on this site like robots with treads. I used to be a fan of treads too but after seeing videos like the ones below I think there are better designs out there. Even 4x4 does pretty well when you look at rock crawlers like the ones in the 4th video

What is your opinion? What is the best or the coolest design you've seen for an all terrain robot?

Have you seen a design that is just "too wierd"?

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OddBot's picture
I agree that for indoor robots, treads are more for show but I would like to see LMR robot builders build more outdoor robots. I think treads have one major flaw, if a tread comes off, the robot is disabled, if a tyre on a 6 wheel drive is flat or damaged then it can still move without too much difficulty. I suspect this is why many mars rovers have 6 wheels.
CaptainTuna's picture
I am not sure about the mars rovers. Proper "NASA" threads shouldn't come off easily. Maybe its because the different gravity conditions make the threads a bit loose..i don't know how to explain this.... You know real threads are not made of rubber like the ones we use, they are not stretched, they are a bit loose, but gravity keeps them on the sprockets. This could have been a problem on the moon. (i would add a big MAYBE at the end :D )
TeleFox's picture
The treads should never be too loose, regardless of gravity, thanks to the suspension. It works like an auto-tensioning idler wheel, a common component added to belt/chain/pulley systems to maintain the correct tension.
Mike's picture

I think part of the answer is that physics/mechanics doesn't seem to scale linearly.

As a kid I built motorised vehicle chasis with Meccano. These included sprung suspension, but the suspension - whether leaf or coil spring - never worked. Eventually I decide that it was because although the chais may have been built to a scale, the flexibility of the materials didn't scale at the same rate, so leaf springs were too stiff and coil springs too soft.

So, what works mechanically for a main battle tank doesn't necessarily work on a scale model of that tank.

even the big tanks throw a tread once in a while, if you look at the WWII tanks you can see the tool onboard that they used to do field repairs on the treads.  The M1A2 abrams mbt can throw a tread. This will happen when too much dirt  or snad gets  in between the tread and sprockets.
OddBot's picture
Is "snad" a technical term or a typo?
jklug80's picture
It is like sand but slightly dififerent.
OddBot's picture
Real life typo sand? :p
OddBot's picture
I don't think there was ever a rover using treads. Spirit and Oppertunity were 6 wheel drive. There are new tyres being developed for rovers but not treads.