Alt-BEAM Archive
Message #08978
To: beam@sgiblab.sgi.com
From: Evaristo Westplate evaristo@qctechnology.nl
Date: Mon, 10 Jan 2000 10:00:44 +0100
Subject: [alt-beam] Re: BIPEDS Was: Pressure Sensors
At 10:04 PM 2000-01-09 -0700, you wrote:
>If they say so, I suppose their is. I didn't see it in the videos but
>it's not VERY noticable with a human either. I disagree with what they
>say about toes. I find myself using them a lot, especially with my shoes
>off, to give a tiny extra push right before I lift it off the groun when
>I'm walking.
Don't our toes work the same as with horses. Isn't the extra push nothing
more then muscles which are stretched (building up energy generated by the
forward movement of the body) and then at a certain point contracted just
like a rubber band. Horses use this principle to covered energy from movement.
>> So Honda engineers opted to avoid the extra complications and control
>> the limb motion to minimize shock. This inherently limits the types of
>> motion the robot can achieve.
True, on easy surfaces the robot can walk but what about slippery surfaces
or sand like surfaces?
>> Here's where pressure sensors come into the picture. Many of the
>> suggestions (including mine) involve some kind of compressive foam --
>> which is a spring. Unless this foam is very thin, you will get
>> significant motion changes as the weight distribution shifts. There will
>> be a magnifying effect as well: divide the height of your robot by the
>> narrowest dimension of a foot ... this is how much any deflection of the
>> pressure sensors will be magnified by.
>
>Ah very true! Did you see Wilf's post? His pressure sensors seem like
>they wouldn't cause this problem too much because theydon't compress a
>heck of a lot as compared to foam. Also I don't beleive this would be
>such a problem with our small, lighter bipeds.
Although the robot may be small so will the feet. The rubber Wilf spoke
about seems useful. Question is where to get it. Wilf?
>> By the way, a biped walker is not that difficult to construct. It has
>> been done with two servos and mechanical linkages. Needless to say, it
>> doesn't look very humanoid, and it sure can't handle uneven terrain.
Is there a web page available about this walker?
See'ya
Evaristo
Gizmo homepage: http://www.crosswinds.net/~evaristo
Biped photos : http://www.crosswinds.net/~evaristo/biped.html
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