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Posted-Date: Fri, 22 Jan 93 08:32:09 -0800
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Date:         Fri, 22 Jan 1993 08:32:09 -0800
From:         Marken@COURIER4.AERO.ORG
Subject:      kugler et al/robot requirements document

[From Rick Marken (930122.0800)]

Avery Andrews says --

>It might be worth figuring out where Turvey et. al. get the following
>absurd idea from:

 > "In control theory, the command-algorithm is separate from the power-flux
 >  that it modulates;  in the neurophysiology of movement, the central
 > nervous system is held conceptually separate from the skeletomuscular
 > apparatus that peforms the movement"

 This doesn't seem absurd to me; in fact, it sounds exactly correct. If by
"command algorithm" they mean the error signal (or the process that
converts perceptual into error signal) and by "power flux" they mean
the forces exerted by the muscles as a result of influence by the error
(command) signal then they are treated separately in control theory --
inasmuch as they are treated as separate variables (which they are).
The "output" part of the control model says that o = f(e). For systems
at the lowest level of the control hierarchy, o could be  called "power flux"
and e could be called the "command signal". They are conceptually
separate. My question for Kugler, Kelso and Turvey, then, is SO WHAT?
What's wrong with treating two separate variables that are functionally
related as two separate variables that are functionally related? The
important thing about control theory is that it also says that e = g(o,p,r,d)
--
that is, the command signal is (at least in part) a result of the very
"power flux" (o) that it commands. This closed loop relationship MUST
be taken into account when analyzing (as you say Rack, etc do) "the
physical properties of the power-generators,  and their effects on the
properties of feedback loop".

So I would say that the above clam is not absurd; it is just irrelevant
(at least, I cannot see it's relevance to anything); it just seems like part
 of the constant desire by conventional psychologists (and roboticists, etc)
to say something about control models of behavior that might be construed
as negative -- but is usually wrong or (like the above) a non-sequiter.
The goal seems to be to dismiss perceptual control models in order to
get on with the real business of wasting time on "self-regulating" systems
(attractors models) and other complex output generation/planning schemes.
---------

Speaking of wasting time, Greg Williams suggested that it might be a good
idea to build a multiple df finger pointing system to impress impressionable
roboticists. I think this is a great idea but I would like to suggest a
time-waste
prevention caveat. We now apparently have several "real" roboticts listening
in on the net. How about asking them to provide a "requirements document"
for such a robot. Clearly we (you, Bill, others and myself) have a very poor
grasp of what might impress our target audience (people who are presumably
interested in understanding the behavior of living --and
artifactual--systems).
I thought my "mind reading" demo would electrify the behavioral science
community -- but NO. I also thought the ARM demo would electrify the
motor control/robotics community -- but NO. I thought my spreadsheet model
would get the attention of behavioral modellers -- but NO. I could go on but
you get the picture. Obviously, what impresses PCTers (actually understanding
things) is not what impresses large segments of the behavioral science
community
(apparently, cute names, trendy tools and attractive surface phenomena). So
let's
forget about guessingwhat might be impressive-- let's ASK; what kind of be-
havioral model (robot) could PCTers build that "real" roboticists,
psychologists,
computer scientists, etc etc  would find impressive. If (as I suspect) all
they want
is impressive surface appearances (the Disneyland syndrome?) then we don't
need
to waste our time; then our goal is to explain why impressive surface
appeances (alone)
are not our goal. But if we have clearly stated requirements for a robot that
controls
multiple df in a realistic environment, then it might be worth it to try to go
 beyond the
ARM and the spreadsheet; otherwise, I think it's a waste of time; as Bill
Powers
keeps finding out, there are too many other things to do.

So this is an open solicitation for contributions to a "robot requirements
document"
(RRD). What behavioral capabilities would be impressive in a robot? These
should
become requirements in the RRD.

Best regards

Rick
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