Subject:
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Re: Classic timing circuits and XOR gates (long)
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 9 Aug 2005 19:23:25 GMT
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Viewed:
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3096 times
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In lugnet.technic, Sigurd van Strakenburg wrote:
> hi kevin,
>
> looks good, only a few thinks are not cleare to my, are the XOR gates somware in
> the body whare the don't have any oder function?.......
> and do the legs just need to keep up whit the central timing system?.....
> or did the walker make sure al legs are dropt (or locked) in the down positoin
> before it move's to the next stap?
> and the last question is: do all the extra pistons and swiches dont take more
> time then the classic timing circuit? because you've made a 12 state cycle with
> extra pistons
Yes, the XOR gates are not load bearing, but somewhere in the body.
I tried to make the legs "just follow allong", but this did not guarantee that
the legs were all weight bearing when needed, and it fell. I added a switch to
each leg hooked serially into a four input AND gate for the first LEG group, and
the same for the second. The central timing circuit can not progress from all
weight bearing to half weight bearing unless *all* the legs are down.
I also added a second switch to each leg to make sure the legs get lifted.
Because of asymmetries, one leg group never really got lifted, before they were
dropped. They are hooked up serially within each leg group, just like the leg
down switches.
Actually, the old and new circuits are about even, except the new one works
faster.
My first attempt at SSClagorpion actually uses a four step sequence:
1. Lift leg, sweept it forward, sweep down leg backwards.
2. Drop leg.
3. Lift leg, sweep it forward, sweep down leg backwards
4. Drop leg.
It uses a two piston central timing circuit (feedback loop as Mark B. calls it)
with ANDs instead of XORs.
_
/ \_ Timing piston A
_
_/ \ Timing piston B
/\__ A and NOT B - lift/drop leg group 1
__/\ B and NOT A - lift/drop leg group 2
But when I add leg up/down synchronization is stretches some:
__
/ \__/ Timing Piston A (Ax <= Bx AND LEG GROUP 1 down)
Ac <= Bc AND LEG GROUP 2 down)
__
__/ \_ Timing Piston B (Bx <= Ax AND LEG GROUP 1 up)
(Bc <= Ac and LEG GROUP 2 up)
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/ \____ A AND NOT B
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_/ \___ leg group 1 lift/drop
_
___/ \_ B AND NOT A
_
____/ \ leg group 2 lift/drop
012345786 Time
012345012 State
So synchronizing the leg up/down stretches the timing from 4 to 6 states.
I did not add synchronization for leg sweep.
> >
> > In the end, these creatures walk slowly, and tend to freeze up and stop walking.
> > This makes them less reliable than I like. When Sigurd showed me his fabulous
> > hexapod walker, he mentioned that he ran into reliability problems too.
>
> the reliability problems wasn't that it freeze up or so only swiches, tubes and
> pistons how ware leaky makes it hard to get working
I've had a lot of problems where the pistons do not have enough force compared
to the load, so the pistons don't throw switches completely and we lock up.
>
> > I guess I've been droning on...... sorry.
>
> don't say...... go on!!!
> >
> >
> > Well, this is another one of my long diatribes about pneumatics, but usually
> > there are at least a few people who wade through a long post like this.
>
> oww yea the do thanks for you're inspiration :)
Sigurd, your building has inspired me to restart building!
>
> >
> > I hope it is comprehensible.
> >
> > Kevin
>
> sigurd (van starkenbUrg ;-)
Kevin
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Message has 1 Reply:
 | | Re: Classic timing circuits and XOR gates (long)
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| In lugnet.technic, Kevin L. Clague wrote: (SNIP) (...) Here is a picture of SSC1 (URL) 1 has eight legs broken into two groups of four. The circuit is based on a two piston, negative feedback loop. This feedback loop can be described as: Piston B (...) (19 years ago, 9-Aug-05, to lugnet.technic)
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Message is in Reply To:
| | Re: Classic timing circuits and XOR gates (long)
|
| hi kevin, looks good, only a few thinks are not cleare to my, are the XOR gates somware in the body whare the don't have any oder function?....... and do the legs just need to keep up whit the central timing system?..... or did the walker make sure (...) (19 years ago, 8-Aug-05, to lugnet.technic)
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