Living Control Systems III: Chapter 1

[David Goldstein (2014.02.02.11:56)]

Rick posed the following study questions:

Bill starts by saying that “Whatever method of control one proposes the
basic concept of control is the same.” He then defines control. Based on what we discussed regarding the Foreward (The Fact of Control) what do you think Bill is getting at in this paragraph.

2, In this chapter Bill discusses two approaches to explaining
control – two versions of control theory: Modern Control Theory (MCT) and Classical Control Theory (which is what PCT is). Bill says that MCT has been a “formidable obstacle to the acceptance of PCT”. Based on your reading of the section on MCT why do you think this might have been
the case? That is, why might the MCT approach to explaining control have been an obstacle to acceptance of PCT?

  1. On p. 9, paragraph 2 Bill says that “A negative feedback controller…doesn’t have to know what is causing the speed [controlled variable] to change.” The rest of the paragraph goes on to explain why this is so and why this distinguishes the PCT (classical) controller from the MCT controller. In your own words can you describe how this description of the PCT model of control differs from the MCT model.

  2. Why do you think Bill included the section on Simulation and Modeling in this chapter?

What would you say is Bill’s point in the last section of the chapter on Philosophy of Science? Why do you think he would include it?

Finally, consider the last sentence of the chapter: “Control, like digestion, is something everyone does but hardly anyone understands.” Is
Bill talking about these things – control and digestion – as theories
or facts?

Here are my answers:

  1. Control is a fact. There are different theories to explain it (classical, modern).

The way Bill describes MCT, one has to know so many things before one can model the fact of control. It seems like one has to predict all the disturbances which will happen.

In PCT, one has to have a good way of assessing the controlled variable. In MCT, one has to have a way of assessing all the disturbances in addition to the controlled variable.

This is his way of doing research. One understands something if one can
create a model which behaves the way a person behaves.

  1. Is there a real world? We all think so. However, all we have are our perceptions of
    it.

  2. Fact.

The whole discussion we have been having about feedback versus feedforward relates to question 2.

bob hintz 2014.02.05

I have my book and I think I will be able to run the demos (I was unable to get the cd to run under “wine” but I was able to boot up a win7 os and it seemed to work ok).

  1. He wants to reveal his point of view.

  2. I find his description of MCT a little strange as there does not seem to be any feedback in this description. I’m guessing the MCT folks are concerned with building the car and learning how to control it.

3.In Bill’s description, the MCT has to figure out the speed without looking at the speedometer. I’m not certain whether it gets to use the gas pedal or steering wheel either, but Bill does admit he is building a straw man. The PCT already knows how to turn on the engine, put the car in gear, (maybe coordinate the clutch and gas pedal if it is standard shift) and the brake if the road starts to slant down at a steep angle. It seems that PCT assumes an educated driver rather than asking how does one learn to drive? It also seems that the driver can watch the speedometer continuously so that any change will be immediately noticed and counter acted.

  1. I think it is for the benefit of those of us who might not be able to deal so easily with formulas and want a different way of exploring relationships.

  2. Living systems have an internal source of energy and can act on the world outside themselves in terms of meaning which they attach to that world as they perceive it.

  3. Fact, but I’m not certain how that is very different from an agreed upon belief.

···

On Sun, Feb 2, 2014 at 11:09 AM, D GOLDSTEIN davidmg@verizon.net wrote:

[David Goldstein (2014.02.02.11:56)]

Rick posed the following study questions:

Bill starts by saying that “Whatever method of control one proposes the
basic concept of control is the same.” He then defines control. Based on what we discussed regarding the Foreward (The Fact of Control) what do you think Bill is getting at in this paragraph.

2, In this chapter Bill discusses two approaches to explaining
control – two versions of control theory: Modern Control Theory (MCT) and Classical Control Theory (which is what PCT is). Bill says that MCT has been a “formidable obstacle to the acceptance of PCT”. Based on your reading of the section on MCT why do you think this might have been
the case? That is, why might the MCT approach to explaining control have been an obstacle to acceptance of PCT?

  1. On p. 9, paragraph 2 Bill says that “A negative feedback controller…doesn’t have to know what is causing the speed [controlled variable] to change.” The rest of the paragraph goes on to explain why this is so and why this distinguishes the PCT (classical) controller from the MCT controller. In your own words can you describe how this description of the PCT model of control differs from the MCT model.

  2. Why do you think Bill included the section on Simulation and Modeling in this chapter?

What would you say is Bill’s point in the last section of the chapter on Philosophy of Science? Why do you think he would include it?

Finally, consider the last sentence of the chapter: “Control, like digestion, is something everyone does but hardly anyone understands.” Is
Bill talking about these things – control and digestion – as theories
or facts?

Here are my answers:

  1. Control is a fact. There are different theories to explain it (classical, modern).

The way Bill describes MCT, one has to know so many things before one can model the fact of control. It seems like one has to predict all the disturbances which will happen.

In PCT, one has to have a good way of assessing the controlled variable. In MCT, one has to have a way of assessing all the disturbances in addition to the controlled variable.

This is his way of doing research. One understands something if one can
create a model which behaves the way a person behaves.

  1. Is there a real world? We all think so. However, all we have are our perceptions of
    it.
  1. Fact.

The whole discussion we have been having about feedback versus feedforward relates to question 2.