Subject:
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Re: SSClagorpion
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 20 Apr 2004 16:37:26 GMT
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Viewed:
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9101 times
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In lugnet.technic, Steve Hassenplug wrote:
> In lugnet.technic, Kevin L. Clague wrote:
> > In lugnet.technic, Steve Hassenplug wrote:
> > >
> > > Ok, we [plan to] have a sensor on the front foot, and can detect when that is
> > > down. So, no more sensors are required.
> >
> > Actualy we need to sense when it is *up*.
>
>
> Is *up* the same as "not down"? I was thinking it was, but that may not be the
> case.
I think that you are right, that they are the same thing.
>
>
> > >
> > > So you said, the forward/backward must be changed while the feet are in the air.
> > > We've been thinking of having a touch sensor on the front feet, so it can detect
> > > when it goes off an edge (like a table). However, it would not know the surface
> > > is not there, until it trys to put the foot down. So, all the feet would be
> > > down, and it needs to backup. Can it do that? Or will it need to keep walking
> > > a bit?
> >
> > As soon as you figure out that a foot is up, you can reverse directions. I'll
> > have to study the state sequence, because there are two non-weight bearing
> > pistons that control the feet, so it might be sufficient to see that they are
> > telling the feet to lift. You might need two touch sensors wire-ORed together
> > (one for each leg group).
>
>
> This sounds like we can NOT do the table edge detection stuff, using it's feet.
Hmmm.... We would need to know two things to determine we'd hit the edge of the
table.
1. The foot is down as far as it will go.
2. The down foot is not touching anything.
We would need one of these sensor pairs for each front foot.
When the foot is down and not touching anything, we wait for the foot start to
rise, and flip the muxes to backwards. At the time the legs get to the top,
they will go backwards, so I don't think we'll walk off the table.
>
> Imagine you're crawling around on your hands and knees, with your eyes closed.
> When you get to the top of a stairway, you put your hand down, and it doesn't
> touch the ground.
>
> If I understand you correctly (which doesn't always happen via e-mail) you must
> continue to crawl forward, until your other hand and knee are off the ground.
>
> That will be a problem.
>
> It's fine if it can't turn, or switch to moving sideways while all feet are on
> the ground, but it really needs to be able to reverse direction.
>
> I suspect the front legs can be a small amount longer, so it will detect the
> lack of ground, before the weight is really shifted to the new legs.
Remember, 7 of the 8 legs will be down at the time we realize that we're at the
edge. Given that pneumatics are slow, we should have plenty of time to slam it
into reverse.
>
> Will that work?
>
> Steve
Kevin
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Message has 1 Reply:
 | | Re: SSClagorpion
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| (...) Right. That's listed somewhere in my prior ramblings. It should work fine with 2 inputs (one for each foot) (...) ... (...) We may need to figure something out, here. I think it WILL be a problem. At any given time, he will (could) have only (...) (20 years ago, 20-Apr-04, to lugnet.technic)
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Message is in Reply To:
| | Re: SSClagorpion
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| (...) Is *up* the same as "not down"? I was thinking it was, but that may not be the case. (...) This sounds like we can NOT do the table edge detection stuff, using it's feet. Imagine you're crawling around on your hands and knees, with your eyes (...) (20 years ago, 19-Apr-04, to lugnet.technic)
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