Subject:
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SSCorpion
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 13 Apr 2004 16:19:44 GMT
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Viewed:
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6721 times
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This will be interesting because it is my first partner build..... and I know of
no pattern to follow. We each have our own approaches and I'm not sure how
similar they are. I figured we might as well do the designing process here on
LUGNET, rather than behind the scenes. If people object, we can take this
conversation offline.
For me, because the pneumatics control plays such a large part, the overall
walking mechanism can have a huge impact on the body design. Now with the
Sophie effect coming into play, we get to consider much more. I like it.
Here is a site that has lots of scorpion pictures. I'll leave it to Eric's
artistic eye to pick the species we're going for.
http://www.ub.ntnu.no/scorpion-files/gallery.php
I start with the overall concept of the walking mechanism..... Inarguably a
scorpion has eight legs, and does not use its own body as a leg, so the body
must stay off the ground during the walking process. I tried unsuccessfully to
find movie clips of scorpions walking, but no lock, so I'll make some
assumptions.
1. Typically they walk forward with two groups of four legs.
2. Turning is done by using a different sweep, primarily with the front two
and back two legs.
If we want to avoid gravity wells, we can use the hex242 circuit with extensions
to support forward and backward movement. We might have to have some special
help for turning (maybe bias the sweep forward or backwards).
The leg sweep will be similar to the way that an oar on a rowboat moves.
Down,back,up,forward.
This requires two pistons (plus two switches each) per leg. One for
forward/backward, and the other for up/down. Each piston has to control two
switches that basically instrument the piston state for the rest of the circuit.
The switches can be anywhere as long as they are mechanically linked to the
expansion and contraction of the piston.
If SSCorpion gets too heavy we can double or triple up pistons for a given
degree of freedon. The multiple pinstons will be mechanically linked so they
all expand at the same rate.
Two groups of four legs is a simple extension to hex242 and hex363.
Scorpion's body looks oval, close to rectangular, so the leg sweeps should be
all about the same mechansim.
The walking mechanism will be completely wired into pneumatics. For walking
backwards, we can use pneumatic polarity reversors controlled by RCX/Motors.
The RCX may need to know that we are in the right state before it changes the
muxes, so that will take some kind of sensor.
Other kinds of articulation could include the claw arms, and/or the tail.
The tail is pretty rigid unless a scorpion is threatened, then the scorpion
tries to make itself bug by standing taller, bringing the tail far forward, and
raising its claws. This is not part of the regular walking mechanism, so we'll
have to figure out if this is pneumatic (my guess for now is no.)
I think that we have a lot of freedom as to the shape of the body, so we need to
work on the hip and leg joints and leg structure.
Eric, do you have enough to work up body and leg stuff? My only constraints are
that there are two switches per piston, and two pistons per leg. Feel free to
add more pistons if you think they are needed.
Kevin
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Message has 4 Replies:
 | | Re: SSCorpion
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| (...) -snip- This is facinating, I am preparing a more in depth response at this moment. e (20 years ago, 13-Apr-04, to lugnet.technic)
| | | Re: SSCorpion
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| (...) I assume you're not counting the Team Magno fiasco. I guess there really wasn't much building involved there. :) (...) ... (...) ... (...) Will this type of design allow it to turn in place, or can it only turn while walking forward/backward? (...) (20 years ago, 13-Apr-04, to lugnet.technic)
| | | Re: SSCorpion
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| (...) This is my first Co-build as well. But not my first multi-person project. I have also witness first hand the success you both have had in working with others and in your own projects. I'm interested in unlocking my potential. I'm interested in (...) (20 years ago, 13-Apr-04, to lugnet.technic)
| | | Re: SSCorpion
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| (...) Well, since nobody has objected, let me just say up front... PLEASE keep it on-line. I agree with Steve, this is fun (and that's just as a spectator). With regards to Steves question about "decoupling" the left and right sides, Kevin, could (...) (20 years ago, 13-Apr-04, to lugnet.technic)
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