Alt-BEAM Archive

Message #04812



To: beam@sgiblab.sgi.com
From: "Zozzles T. Freep" zozzles@lanl.gov
Date: Wed, 23 Jun 1999 01:41:21 -0600
Subject: [alt-beam] Wow! Observations! (was: Ah! Blessed Skepticism!)


Wilf Rigter wrote:
:> To a standard suspended Bicore add a BG micro motor directly to the
:> Bicore outputs
...
:> So there it is
:> mechanical AND electronic feedback. Obviously the rotation is reduced by
:> mechanical loading BUT the pulsewidth is also reduced.
...
:> If the Bicore output is buffered before connecting to the motor, the output
:> pulse duration is actually slightly longer when the motor is loaded...

Bruce Robinson wrote:
:But you are driving the motor directly from the bicore, so there could
:well be a direct influence on the circuit. I was taking exception to the
:idea of a drop in supply voltage having a significant effect on the Nv
:delay.

Understood, Bruce, but he -is- showing that implex appears to exist -- at
least for the bicore. Actually, I was finally convinced of implex quite
some time ago, but figured that buffering would nullify its effect.
Apparently this isn't correct but then neither is Tilden's conjecture that
adding a feedback resistor would cause it to reappear. I am, at this
point, interested in whether Wilf used the same chip for buffering or
another.

Ain't actual experimentation grand? My hat is off (yet
again) to Wilf!

However, Wilf acknowledges what I consider to be the second part of the
problem (and probably the more important) -- does implex actually help the
robot in any way, is it _valuable_ to the robot? What are your "values"
in the first place? Tilden's third law, for example, depends on overall
architecture and it certainly doesn't depend on the nervous net. And once
you've got those values, how to measure, how to measure? I assert that it
would take continuous, objective observation of your Jurassic Park to even
begin to address this problem -- five minutes now and then won't do it.


Now, when Wilf writes:

:> ...even if a small resistor is introduced in series with the
:> powersupply to reduce supply voltage under load (so much for powersupply
:> feedback).

isn't he confirming what you are thinking in the first place?


Zoz




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