Alt-BEAM Archive

Message #03696



To: beam beam@corp.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Tue, 25 May 1999 12:21:15 -0500
Subject: [alt-beam] Re: Spyder (was: Mr. Tilden & Co. on Discovery Channel)


I think I'm going to work on the Nv net for my Spyder this week.
Hopefuly I won't get lazy! (:

This may be an interesting week! TWO working robots??? Hope things work
the first time for me, as usual! Bwahahahahahaha!!! (:

"John A. deVries II" wrote:
>
> At 05:16 AM 5/25/99 , George Rix wrote:
> >An awesome shot of Spyder walking!
> >Or trying, anyhow, Mark's hand was preventing that, as Spyder's legs
> >couldn't reach the table =)
>
> Was some reason given for not permitting Spyder to walk??
>
> Speaking of which, Spyder is one of those robots about which you read "it
> _learns_ to walk in just... (4? 10?) steps" as if some sort of magic
> convergence takes place. Actually, I think what happens is the following:
>
> (a) both the central microcore and the leg chains come up saturated.
> (b) as a result of the leg chains being saturated, the leg motors make
> fairly uncoordinated motions -- call them "steps" if you will, but I
> wouldn't. More like twitches.
> (c) until the PNC "cleans up" the central microcore, processes from it
> continue to be fed to the leg chains, causing them to continue in their
> relatively uncoordinated fashion.
> (d) chances are there is a brief period between the time that the excess
> processes are extinguished by the PNC and the PNC releases, during which
> the legs calm down.
> (e) finally, the PNC releases and a process is allowed to circulate around
> the central microcore.
> (f) it probably takes two circuits of that process around the microcore
> before the leg chains are properly initialized and the legs appear to act
> in a coordinated fashion.
>
> No magic chaotic emergence, no learning, although the actual amount of time
> between turn-on and coordinated movement will vary. Speaking of which,
> given the arrangement of Spyder's legs (diagonally distributed at the
> corners of a rectangle) how does it walk very well at all (in fact I have
> seen it walk reasonably well) ? How can it be made to turn? Finally, is
> Spyder indeed the robot described by the patent or has stuff been added
> between the time of the patent and its current state?
>
> Any thoughts?
>
> Zoz
>
> ---------------------------------------------------------------
> John A. deVries II
> zozzles@lanl.gov

--


Richard Piotter
richfile@rconnect.com

The Richfiles Robotics & TI web page:
http://richfiles.calc.org

For the BEAM Robotics list:
BEAM Robotics Tek FAQ
http://people.ne.mediaone.net/bushbo/beam/FAQ.html

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