Hi Rick,
RM: If error is small then the controlled perceptual variable is being
kept close to the reference: p is being kept approximately equal to r. This is
happening because the actions of the control system are compensating for the
net effect of all disturbing influences on the controlled variable. Thus, the
actions of the control system can be said to protect the controlled variable
from disturbances that would move it from its goal or reference state. It
is the controlled variable – not the control system-- that is protected from
the effects of disturbances.
HB :
Term “protection” has probably
some exact meaning. And in our discussion you showed that you don’t respect
much “enforced definition” as you tried to change also Bill’s
definition with “Princing approach”. L
So I don’t know exactly what are you
talking about. But when using difference betwen your and Bill’s definition I
was refering to your previosuly known “definition” of
“protection”…in which was quite clear that you were talking about
“disturbances not affecting controlled variable”. So whatever you
wrote above is totaly new to me. From your previous “defintions” I
understood as you were talking about “permanent-able” not
“variable” protected from disturbances.
RM earlier :
…that Douglas (and
Ashby) calls “stability” – the return of a variable to the initial,
equilibrium or zero state after a transient disturbance
– is different than the
behavior called “control” – where a variable remains in an initial,
equilibrium or zero state, protected from the effects of disturbance (sorry
Boris).
HB :
I think you are misleading PCT’ers and “watchers”
of PCT.
If you would know somethnig about how
organisms work (as Complex Control Systems) you would know that control units
(bilions of them) are afected all the time by disturbances from internal and
external envoironment and they affect all the time whatever is happening to
behavior and outside environment (as the consequence of what is happening all
the time inside organism). It’s quite complex control problem and I’m not sure you
could understand that yet, because you’re all the time working with (quite
abstract) mathematical model which could also result in “blind
street”.
So whatever you are describing as
“controlled variable” and “control system” or complex LCS system
are always exposed as the whole to all kinds of various both environmental disturbances.
I deliberately used term “system” as I think that once PCT will have
to face the problem that Rupert Young excelently exposed about Human Brain
Project in EU : how to simulate working of Central Nervous System with PCT. That
is reasonable goal for me. Nobody answered his challenge, because probably
nobody inside PCT group posses such a knowledge to do that. I doubt also that
with joint effort of all members we could do that. But once I hope will be able
to do that. That’s a huge project for PCT and probably “the strongest
test” outside PCT group to prove the highest value of “Perceptual
Control Theory”.
As for the moment you would really do a
favor to PCT if you stop using term “protection” and start using generic
control terms. And this problem occured in Chapter 2 of LCS III. So I suppose
we should be using strictly terms used in this book and Chapters, And I
couldn’t find place where Bill in Chapter 2 used term “protection”. Would
you be so kind and help me find it ?
Best,
Boris
···
From: Control Systems Group
Network (CSGnet) [mailto:CSGNET@LISTSERV.ILLINOIS.EDU] On Behalf Of Richard Marken
Sent: Tuesday, February 11, 2014
7:19 PM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: LCS III: Study Guide
for Chapter 2
[From Rick Marken (2014.02.11.1020)]
On Tue, Feb 11, 2014 at 7:43 AM, Boris Hartman boris.hartman@masicom.net wrote:
Hi Adam,
BH:If I understood right, you used term “protected” in
the sense of control. If control is good (“error” small or zero),
then it seems that control system is “protected” against
disturbances.
RM: If error is small then the controlled perceptual variable is being
kept close to the reference: p is being kept approximately equal to r. This is
happening because the actions of the control system are compensating for the
net effect of all disturbing influences on the controlled variable. Thus, the
actions of the control system can be said to protect the controlled variable
from disturbances that would move it from its goal or reference state. It
is the controlled variable – not the control system-- that is protected from
the effects of disturbances.
Best
Rick
It seems somehow to me, that you used term “protected” in
the same meaning as Bill (Powers) did.
I was quite sure that you didn’t use Rick’s “definition”
of “protection from disturbances”. But I wanted to be sure about
that. Your answer was quite clear. Thanks.
Good luck (puno sreče) J,
Boris
From: Control Systems Group
Network (CSGnet) [mailto:CSGNET@LISTSERV.ILLINOIS.EDU]
On Behalf Of Adam Matic
Sent: Tuesday, February 11, 2014
10:40 AM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: LCS III: Study Guide
for Chapter 2
On Tue, Feb 11, > 2014 at 7:06 AM, Boris Hartman boris.hartman@masicom.net > wrote:
AM :
The point is to
demonstrate the concept of control, to get a feel for what it means to control
an aspect of the environment and protect it against disturbances.
HB :
Could you trace the
control loop without disturbances (d) ? So what happens with the control loop,
if you “delete” disturbances from PCT diagram in the sense that you
“protect” an aspect of environment (I assume you meant outer
environment) against disturbances.
I also assume you
meant that disturbances in the case of “protection” don’t affect
“aspect of environment” or “controlled variable” in
environment. Did I understand right ?
AM:
Hi Boris,
I meant that the
point of the first demo is to convey the meaning behind the concept of control.
The person using the demo controls some aspect of the environment that he or
she chooses, the controlled variable. What that means is
(1) there are
quantities in the environment we, as control systems, sense and perceive;
(2) we can simply
choose which quantity we wish to control and at what level we want it to be;
(3) maintaining
the quantity on the desired level is control
Anything that
tries to move our controlled quantity from the desired level is a disturbance,
and to “protect the controlled quantity” would be synonymous to
“maintain the controlled quantity on the desired level.” At least,
that is how I understand these terms. I don’t mean that disturbances should be
deleted from the diagram, I use the term ‘protect’ to mean ‘maintain’.
Best,
Adam
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Richard S. Marken
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www.mindreadings.com
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