Subject:
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Re: 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 22:10:44 GMT
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Viewed:
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7273 times
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In lugnet.technic, Steve Hassenplug wrote:
> In lugnet.technic, Kevin L. Clague wrote:
> > This will be interesting because it is my first partner build.....
>
> I assume you're not counting the Team Magno fiasco. I guess there really wasn't
> much building involved there. :)
>
> > 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.
>
> ...
> >
> > 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.
With four polarity reversors (16 pneumo switches), we can make it walk
forward, backward, turn right or left. If we used more polarity reversors we
could make one side walk forward, while the other side turns, leading to a
curved walking path.
>
> ...
> > Two groups of four legs is a simple extension to hex242 and hex363.
>
>
> Will this type of design allow it to turn in place, or can it only turn while
> walking forward/backward?
All of the above.
>
> I think it should be able to turn in place. That could mean dis-connecting the
> legs on each side.
Nope, just dilligent reversal of horizontal leg sweep.
>
> Also, moving sideways would be cool. That would mean adding a side-to-side
> piston, to go along with the forward/back piston on each leg. Right?
Yes, I think this would take a third degree of freedom in the legs.
>
> Thoughts?
Plenty of them.
>
>
> >
> > 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.
>
>
> The control could be Motor->pneumatic switch for:
> A) Forward/Backward/Stop (x2) (one for each side, as in diff drive)
> or
> B) Forward/Backward and a second switch for Stop/Go (x2)
> or
> C) Forward/Backward, Stop/Go, Same/Opposide (legs on both sides go same
> direction or opposite direction)
We have to use polarity reversors in pairs. If we reverse the leg sweep, by
swapping pressure hoses, then we need to swap the AND gate outputs (two
pneumatic switches) also.
For walking backward, we reverse *all* the leg sweeps, and reverse the output of
the sweep complete AND chains. This requires one motor to flip these two
reversors.
For turning, we reverse *half* the leg sweeps, and reverse the AND gate outputs
for the same pistons. We can hose things together so we can use only one
reversor for this. So turning requires one motor to flip these two reversors.
Since you want to stop, you probably want to use a motor and a single pneumo
switch to the *off* position.
>
> Any thoughts about what works well, Kevin?
Yep.
>
>
> > Other kinds of articulation could include the claw arms, and/or the tail.
>
> The claw is a must. As is curling the tail.
>
> But, do the arms move?
>
> As I said, I'd like to see sensors on the arms, somewhat like antenna, so when
> it's being autonomous, it can detect objects. And on the front feet, so it can
> avoid falling in holes, or walking off tables.
>
>
> The first challenge I see from our brief discussions, is that Eric builds
> backward. :) I think both Kevin and I start from the inside, and build out.
> While Eric starts on the outside, and builds in.
>
> I usually worry about how my robot look, but that's secondary to how they work.
Yes, I noticed this too.
I'm going to prototype out some leg designs, but suspect/hope that Eric will
just use these to get started, and will redesign the joints from the outside in.
;^)
>
> This is fun.
>
> Steve
Yes, this is fun!
Kevin
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Message has 1 Reply:
 | | Re: SSClagorpion
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| (...) Ok, so I'm thinking about motors to flip pneumo-switches. Each of these may be one or more switches, all activated at the same time. 1) Switch for Start/Stop (on/off) When this switch is "on" the scorpion will be walking. (legs going up/down + (...) (20 years ago, 14-Apr-04, to lugnet.technic)
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Message is in Reply To:
| | 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)
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