Alt-BEAM Archive
Message #08831
To: beam@sgiblab.sgi.com
From: "Nathaniel Martin" nat@lumiere.net
Date: Wed, 5 Jan 2000 12:29:40 -0600
Subject: Re: Biped Beam Bots
> Nice bots, Ian and Evaristo.
>
>
> Here's my idea for a Biped BEAM 'Bot ("BBB"). I'll try to build it after I
> build a 2 motor 4-legged BEAM bot (A. Miller type.)
>
> Remember, I'm a newbie at this, so tell me if what I'm thinking is
impossible:
>
>
> Basically, I would keep walking and balancing separate.
>
> The robot would be "chicken legged" with the knees angled back. It would
> have two servos on the hip, one servo on the knee, and an
> electro-mechanical clutch on the ankle (I'll get to that later.)
>
> I would use a few microcores to get a basic walking rhythm:
>
> 1. Move left leg in air and rotate forwards (loosen ankle clutch)
> 2. Straighten left leg (moves foot down) until pressure sensors on the
left
> foot read that they have touched something.
> IF: the leg is completely straight and it hasn't touched anything
> (like
> with a cliff) then 1: Bend leg again
> 2: Move leg left (at hip)
> 3: go back to number 2
> 3. Lock ankle clutch (the clutch allows the foot to rotate to work with
> rough surfaces)
> 4. Bend knee while rotating leg back and straighting right leg (moves the
> body of the BBB forward.)
>
> Repeat for right leg.
>
> Now this would walk, but it would fall down. Here's how it would balance:
>
> I would have a "tail" to balance it. I put tail in quotes because it can
be
> in front of the bot or in back, so it isn't exactly like a real tail.
>
> The tail would be on top of the bot. Basically it would be a fairly long
> rod (compared with the BBB) with a fairly heavy (compared to the BBB)
> weight on the end.
>
> I would have 4 (or more) tilt switches on the BBB.
>
> I would have a very simple circuit: If a tilt switch registers a tilt, it
> moves the tail to the opposite direction of the tilt to reposition the
> center of gravity.
>
> The tail would have 2 DOF so that it can go anywhere above the 'bot.
>
>
> Did I explain this well?
>
> Do you guys think this would work?
>
>
> -Nathaniel Martin
> nat@lumiere.net
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