Alt-BEAM Archive
Message #03189
To: "Paul B. Webster." pwebster@clinipath.com.au,
From: Dennison dennlill@buffnet.net
Date: Tue, 11 May 1999 08:14:55 -0400
Subject: [alt-beam] Re: Incapable robots-Give 'em feet.
Ahh, but look at the size comparison between our bot's and insects. If I set
my bot down in the grass, the wire legs go right through the blades of grass
to the ground. Then, because of their size and weight, there thin points
legs stick right into the soil. I don't dissagree a walker of ours on
insect scale could manage a lawn.
>
> Come now. Insects don't drag their legs in the grass, they *step*
>over things. The problem is that your so-called "walkers" aren't
>walkers at all, they're "shufflers" akin to a person who has had a
>stroke!
>
> Put real legs on the thing, with independent drives to each joint and
>two axes of freedom at the hip and drive each joint with an independent
>processor like all *real* insects have. *Then* you'll see walking.
>
True, but I was keeping in the relm of "not to hard for most people".
Personally I keep thinking about taking that lynxmotion kit and beaming it.
> Size? Watch a few stick insects or mantis. They have no problems.
>Or those giant spiders.
>
> Something else (two things actually) most insects have: Wrists and
>*claws*! With algortithms for extraction from crevices. Using these,
>they "walk" over walls and ceilings.
True, I think feet would still help here.
>
> But please don't whinge about problems with your "insect design".
Whine?!?! I wasn't whining at all, personally I was going about
experimenting. I wasn't just tossing my bot into the grass and then stomping
away frustrated when it didn't work. :-) I was switching legs, and trying
different shapes and stuff. This is fun! I was just posting my observations.
My latest five motor walker, has long feet pads like one of Mark T's
Unibugs. So far it shows much grater ability, as it can balance on two feet,
which means it doesn't drag anything.
>
>> To this I have a few suggestions for building more capable robots.
>> Make them larger.
>> You've just contradicted yourself.
No, I ment larger bots with feet, to keep the wire for sinking into the
ground. Other than that, these larger bots would have large and more
powerfull motors which are less likely to get bogged down with stuff like
grass. My current bots now, if I sit them in the grass, the grass is taller
than them. A bot I could see over the grass.
>
>> With this increased size they will have greater weight (A necessity
>> for nagivating grass and stuff).
>
> No. Insects negotiate grass. You can crush it if you like, it's
>faster but takes (wastes) more energy. Fine if you are *much* bigger,
>but you *can* simply climb over it instead.
Well both are right. Insects do navagate grass, but they are much smaller,
much bigger animals simple climb over and crush it. I was noting that there
aren't too many animals, of similar build, that are the size of our robots.
Sure squirlls and rats and stuff, but not only are they much more
complicated than insects, their energy potential higher, but they also have
spines, which I think contributes to their locomotive ability.
>
>> Give them Paws. All our robots are these things balanced on the ends
>> of wire. Thats no good. These things need some feet. With feet they
>> wouldn't get so bogged down in Grass or sand. With feet they are
>> better balanced.
>
> Feet are used for some balance in bipeds (which have big feet!). They
>are not otherwise *necessary* for balance but they *need* ankles.
>Tripod stance is adequate. I agree on one aspect - large feet *are*
>used to supporte *large* animals on soft surfaces. Many others however
>still have quite small feet.
True, but they all have feet none the less. Sure some feet aren't huge, but
they tend to be pretty proportional.
>
>> The robot can stand on top of more stuff. (kinda like snow shoes) and
>> the legs won't get caught so much in every little nook and cranny.
>
> True enough if you go to a real *big* thing, say a large dog or
>bigger.
Wouldn't that be cool?
Dennison
>--
> Cheers,
> Paul B.
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