Alt-BEAM Archive

Message #03872



To: beam@corp.sgi.com
From: "John A. deVries II" zozzles@lanl.gov
Date: Fri, 28 May 1999 10:47:39 -0600
Subject: [alt-beam] Re: What Tilden calls it.....


At 08:45 AM 5/28/99 , Jason - wrote:
>Hie here is some tips i got over the years from mark T

>>wut is the best materail for me to use as a leg for my walker
>
>Easy. Broken collapsable umbrellas are the best and cheapest form of high
>reliablity leg.

Of course, one can also get decent piano wire (or other stiff steel wire
with a range of diameters) from hardware stores and hobby shops. This is
particularly useful if you don't have a supply of broken umbrellas.

>>and what is the main theory of the master and slave system
>
>A suspended bicore master will always robustly control-lock a phase-slave
>bicore regardless of structural permutation.

It seems to me that one permutation would involve breaking both connections
between the master and the slave at which point there would be no
synchronization ("control lock"). In fact, this is one of the things that
I find bogus about the Snakebot demonstration -- Rigter showed that it only
takes one of the two connections between the master and slave bicore to
ensure synchronization. Snakebot consists of three bicores (one for each
motor/segment) and has at least six connections (between bicores -- I'm not
sure if there is one more pair between 'head' and 'tail'.)

During his demonstration, Mark takes out a coupling resistor... and the
robot continues to work. He takes out another, and then a third and the
robot still functions. Finally, when he takes out a fourth, the robot
becomes uncoordinated. Of course, he isn't taking out a parallel -pair- of
coupling resistors at one time: in other words, I'm pretty sure that if
you could disable the robot merely taking out two connections which would
obviously seem less dramatic than four. . .

Of course, I could be wrong -- I often am.


Zoz

---------------------------------------------------------------
John A. deVries II
zozzles@lanl.gov

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