[Attachment Removed] Revised Hammer and Nail Model

[From Fred Nickols (2015.11.14.0815)]

Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

I am most interested in any comments about the Feedback Function. Do I have that right?

image00216.png

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance”

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

image0011.emz (12.3 KB)

[From Rick Marken (2015.11.14.0810)]

image00216.png

···

Fred Nickols (2015.11.14.0815)

Â

FN: : Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

FN: I am most interested in any comments about the Feedback Function. Do I have that right?

RM It’s diagram is perfect now, Fred. The feedback function is exactly right.Â

RM: Though I don’t know why I care anymore. Homo sapiens is clearly a failed species. I don’t know anymore whether the existence of Einstein, Beethoven, Shakespeare and Powers compensates for what happened last night.Â

Best

Rick

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â


Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[From Rick Marken (2015.11.14.0820)]

image00216.png

···

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Thanks

Best

Rick

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.14.1248)]

Rick asked for a .gif version. Here it is.

image00216.png

image00242.jpg

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.0820)]

Fred Nickols (2015.11.14.0815)–

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.

Thanks

Best

Rick

I am most interested in any comments about the Feedback Function. Do I have that right?

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.14.1251)]

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

image00126.png

image00216.png

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.0820)]

Fred Nickols (2015.11.14.0815)–

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.

Thanks

Best

Rick

I am most interested in any comments about the Feedback Function. Do I have that right?

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

[From Rick Marken (2015.11.14.1130)]

image00126.png

image00216.png

···

 Fred Nickols (2015.11.14.1251)

Â

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

BestÂ

RickÂ

Â

Â

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.0820)]

Â

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Â

Thanks

Â

Best

Â

Rick

Â

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

image00126.png

image00216.png

···

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

 Fred Nickols (2015.11.14.1251)

Â

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

BestÂ

RickÂ

Â

Â

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.0820)]

Â

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Â

Thanks

Â

Best

Â

Rick

Â

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble


Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[John Kirkland 2015.11.15.0920 Oz time]

Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

These two minor edits could then accommodate subsequent hammer swings. Why? When I drive in a nail I start with strong blows and then use less force when the nail is almost home to prevent timber bruising.

I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

Kind regards

JohnK

image00126.png

image00216.png

···

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

 Fred Nickols (2015.11.14.1251)

Â

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

BestÂ

RickÂ

Â

Â

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.0820)]

Â

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Â

Thanks

Â

Best

Â

Rick

Â

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble


Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

I am most interested in any comments about the Feedback Function. Do I have that right?

image0044.png

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.

[From Rick Marken (2015.11.14.1615)]

image00216.png

image00126.png

···

John Kirkland (2015.11.15.0920 Oz time)

JK: Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

JK: I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

RM: I think it offers what you described here as “deploying higher-order reference levels”; in PCT it’s called "going up a level. The only thing PCT would add is that Pericles, Lincoln, Ataturk and others should have done it before they got into the conflict. Lincoln was a brilliant and very humane guy but I think it’s pretty clear now that keeping the South in the Union was the biggest mistake a US President had made until Bush invaded Iraq. Â Â

BestÂ

Rick

Â

Kind regards

JohnK

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

 Fred Nickols (2015.11.14.1251)

Â

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

BestÂ

RickÂ

Â

Â

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.0820)]

Â

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Â

Thanks

Â

Best

Â

Rick

Â

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble


Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.14.1956)]

Thanks but no thanks. Height is a variable. That is indicated as Qi. The reference signal specified a value for the variable. I expressed it as “flush with the deck.� I could just as easily have expressed it as “0 inches above deck surface.� The perceived value of the variable is ½ inch above the deck surface. That yields an error with a value of ½ inch. I see no point in removing the ½ inch specification.

Fred Nickols

image00126.png

image00216.png

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 7:16 PM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.1615)]

John Kirkland (2015.11.15.0920 Oz time)

JK: Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

JK: I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

RM: I think it offers what you described here as “deploying higher-order reference levels”; in PCT it’s called "going up a level. The only thing PCT would add is that Pericles, Lincoln, Ataturk and others should have done it before they got into the conflict. Lincoln was a brilliant and very humane guy but I think it’s pretty clear now that keeping the South in the Union was the biggest mistake a US President had made until Bush invaded Iraq.

Best

Rick

Kind regards

JohnK

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

Fred Nickols (2015.11.14.1251)

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

Best

Rick

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.0820)]

Fred Nickols (2015.11.14.0815)–

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.

Thanks

Best

Rick

I am most interested in any comments about the Feedback Function. Do I have that right?

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.14.2000)]

Hmm. You make me think, Bruce. Certainly, how “hard” I swing the hammer alters the force with which it strikes the nail and I certainly agree with your other comments about controlling the arc of the swing, etc., which is why I added “Hammering” to “Swinging.” I also wouldn’t want to swing “too hard” the first time for fear of doing what John pointed to, namely, bruising the plank or creating a big indentation.

Except for “resistance” the disturbances I listed are those factors that can lead to a nail moving upward. Resistance is a factor when I try to drive the nail back down. I think it is still a disturbance.

As for “my purposes” they are being addressed. I suspect that a simple, physical act such as driving a nail entails several levels of the hierarchy. I wonder if a model of nail driving could be developed and how many levels and which ones would be involved?

Fred Nickols

image0044.png

···

From: Bruce Abbott [mailto:bbabbott@frontier.com]
Sent: Saturday, November 14, 2015 7:00 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

I am most interested in any comments about the Feedback Function. Do I have that right?

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.

[From Rick Marken (2015.11.14.1830)]

image00216.png

image00126.png

···

Fred Nickols (2015.11.14.1956)

Â

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).Â
Â

FN: Thanks but no thanks. Height is a variable. That is indicated as Qi. The reference signal specified a value for the variable. I expressed it as “flush with the deck.� I could just as easily have expressed it as “0 inches above deck surface.� The perceived value of the variable is ½ inch above the deck surface. That yields an error with a value of ½ inch. I see no point in removing the ½ inch specification.

RM: What you are doing is showing a snapshot of the state of the control system at one instant in time; the instant when the nail is 1/2 inch above the plank. That’s OK. I usually think of the diagram as a functional representation of controlling so the implication is that the variables are varying over time. But if you like the snapshot that’s fine. But I think it somewhat misrepresents the reality of controlling, which is a dynamic process.Â

BestÂ

RickÂ

Â

Â

Fred Nickols

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 7:16 PM

To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.1615)]

Â

John Kirkland (2015.11.15.0920 Oz time)

Â

JK: Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

Â

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

Â

JK: I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

Â

RM: I think it offers what you described here as “deploying higher-order reference levels”; in PCT it’s called "going up a level. The only thing PCT would add is that Pericles, Lincoln, Ataturk and others should have done it before they got into the conflict. Lincoln was a brilliant and very humane guy but I think it’s pretty clear now that keeping the South in the Union was the biggest mistake a US President had made until Bush invaded Iraq. Â Â

Â

BestÂ

Â

Rick

Â

Â

Kind regards

Â

JohnK

Â

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

Â

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

Â

 Fred Nickols (2015.11.14.1251)

Â

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Â

Thanks Fred!

Â

BestÂ

Â

RickÂ

Â

Â

Â

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

Â

[From Rick Marken (2015.11.14.0820)]

Â

Fred Nickols (2015.11.14.0815)–

Â

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

Â

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.Â

Â

Thanks

Â

Best

Â

Rick

Â

Â

Â

I am most interested in any comments about the Feedback Function. Do I have that right?

Â

Â

Â

Regards,

Â

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble

Â

Â

Â

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose

Now available from Amazon or Barnes & Noble

Richard S. MarkenÂ

www.mindreadings.com
Author of  Doing Research on Purpose
Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.15.0548)]

Correct. The diagram presents a snapshot at a point in time; in this case, the starting point for driving the nail down flush with the deck. That said, if I do as John suggested, the diagram fits the starting point and points along the way as the height of the nail head above the plank is reduced. So, on second thought, I’ll do as John suggested.

Fred Nickols

image00126.png

image00216.png

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 9:28 PM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.1830)]

Fred Nickols (2015.11.14.1956)

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

FN: Thanks but no thanks. Height is a variable. That is indicated as Qi. The reference signal specified a value for the variable. I expressed it as “flush with the deck.� I could just as easily have expressed it as “0 inches above deck surface.� The perceived value of the variable is ½ inch above the deck surface. That yields an error with a value of ½ inch. I see no point in removing the ½ inch specification.

RM: What you are doing is showing a snapshot of the state of the control system at one instant in time; the instant when the nail is 1/2 inch above the plank. That’s OK. I usually think of the diagram as a functional representation of controlling so the implication is that the variables are varying over time. But if you like the snapshot that’s fine. But I think it somewhat misrepresents the reality of controlling, which is a dynamic process.

Best

Rick

Fred Nickols

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 7:16 PM

To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.1615)]

John Kirkland (2015.11.15.0920 Oz time)

JK: Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

JK: I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

RM: I think it offers what you described here as “deploying higher-order reference levels”; in PCT it’s called "going up a level. The only thing PCT would add is that Pericles, Lincoln, Ataturk and others should have done it before they got into the conflict. Lincoln was a brilliant and very humane guy but I think it’s pretty clear now that keeping the South in the Union was the biggest mistake a US President had made until Bush invaded Iraq.

Best

Rick

Kind regards

JohnK

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

Fred Nickols (2015.11.14.1251)

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

Best

Rick

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.0820)]

Fred Nickols (2015.11.14.0815)–

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.

Thanks

Best

Rick

I am most interested in any comments about the Feedback Function. Do I have that right?

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.15.0556)]

Here is the modified PNG version absent the ½ inch descriptors.

Fred

image0036.png

image00126.png

image00216.png

···

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 9:28 PM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.1830)]

Fred Nickols (2015.11.14.1956)

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

FN: Thanks but no thanks. Height is a variable. That is indicated as Qi. The reference signal specified a value for the variable. I expressed it as “flush with the deck.� I could just as easily have expressed it as “0 inches above deck surface.� The perceived value of the variable is ½ inch above the deck surface. That yields an error with a value of ½ inch. I see no point in removing the ½ inch specification.

RM: What you are doing is showing a snapshot of the state of the control system at one instant in time; the instant when the nail is 1/2 inch above the plank. That’s OK. I usually think of the diagram as a functional representation of controlling so the implication is that the variables are varying over time. But if you like the snapshot that’s fine. But I think it somewhat misrepresents the reality of controlling, which is a dynamic process.

Best

Rick

Fred Nickols

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 7:16 PM

To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.1615)]

John Kirkland (2015.11.15.0920 Oz time)

JK: Just wondering Fred (et al) — if the “perceptual signal” description may be changed to remove the bracketed comment, and for “error signal” deleting the first two words.

RM: Exactly right John, they should definitely be changed as you suggest. I was too quick in my praise of the new diagram. The way it is labeled now still makes it look like the perceptual and error signals are constants (1/2 inch). They are variables, not constants, and they are certainly not measured in inches (or centimeters for that matter); they are measured in units of neural current (spikes/sec).

JK: I’m sure everybody’s noticed; the humanitarian card is now being played as a game changer. It’s from the same deck as Pericles, Lincoln, Ataturk (Gallipoli) and others dealt from in an attempt to deploy higher-order reference signals. Let’s follow through here, what else can PCT offer to the public domain, or ourselves in such a shattering crisis?

RM: I think it offers what you described here as “deploying higher-order reference levels”; in PCT it’s called "going up a level. The only thing PCT would add is that Pericles, Lincoln, Ataturk and others should have done it before they got into the conflict. Lincoln was a brilliant and very humane guy but I think it’s pretty clear now that keeping the South in the Union was the biggest mistake a US President had made until Bush invaded Iraq.

Best

Rick

Kind regards

JohnK

On Sun, Nov 15, 2015 at 10:22 AM, John Caines johncaines@gmail.com wrote:

Here’s 2 more versions, framed, 1 is vintage look!
https://www.dropbox.com/s/tc51shblhhe7fl8/1.jpg?dl=0
https://www.dropbox.com/s/wt08818fp7bnt3i/2.png?dl=0
:slight_smile:

On 14 November 2015 at 19:29, Richard Marken rsmarken@gmail.com wrote:

[From Rick Marken (2015.11.14.1130)]

Fred Nickols (2015.11.14.1251)

The GIF version of the model didn’t render as nicely as I’d hoped. Below is a PNG version. It turned out nicely.

Thanks Fred!

Best

Rick

From: Richard Marken [mailto:rsmarken@gmail.com]
Sent: Saturday, November 14, 2015 11:18 AM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

[From Rick Marken (2015.11.14.0820)]

Fred Nickols (2015.11.14.0815)–

FN: Based on comments (mostly from Rick) I’ve revised the hammer and nail formal PCT model. See below.

RM: By the way, Fred, could you send the diagram in a different image format, like .png or .gif. I’d like to use it, if that’s ok with you, and I can’t easily read .emz files.

Thanks

Best

Rick

I am most interested in any comments about the Feedback Function. Do I have that right?

Regards,

Fred Nickols, CPT

DISTANCE CONSULTING

“Assistance at a Distance�

The Knowledge Workers’ Tool Room

Be sure you measure what you want.

Be sure you want what you measure.

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.

Now available from Amazon or Barnes & Noble

[From Fred Nickols (2015.11.15.0605)]

Bruce Abbott says that the force with which the hammer strikes the nail head is Qo, not the feedback function. He also suggests that the feedback function is the relationship between that force and nail movement and that is affected by resistance (which is not a disturbance). I can see how resistance to nail penetration is not a disturbance and I can remove that from the list of disturbances but what goes in the Feedback Function box?

Fred Nickols

image0044.png

···

From: Bruce Abbott [mailto:bbabbott@frontier.com]
Sent: Saturday, November 14, 2015 7:00 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

I am most interested in any comments about the Feedback Function. Do I have that right?

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.

[From Rick Marken (2015.11.15.1220)]

···

Fred Nickols (2015.11.15.0605)

FN: Bruce Abbott says that the force with which the hammer strikes the nail head is Qo, not the feedback function.

RM: The feedback function is the connection between the output variable, Q.o, and the controlled input variable, Q.i. In the hammer example, it is the connection between the proximal output of the nervous system, which is the variations in muscle tension caused by the error signal (an efferent neural signal). The muscles are the immediate environment of the nervous system, which is the 'Controlling System" in the diagram. So Q.o is really variations in muscle tension caused by variations in error signals going to the muscles. The “feedback function” is everything that connects these muscle tension variations, Q.o, to variations in the the height of the nail head above the plank, Q.i. That is, the feedback function is the whole causal connection from output (muscle tension variations, Q.o) to controlled input (Q.i, nail height). So the feedback function for the hammering example would look something like this:

RM: Muscle tension variations (Q.o) --> variations in arm movement/force–> variations in hammer movement/force --> force exerted by hammer on nail head --> change in height of nail above plank (Q.i)

where the arrows indicate causality.

RM: Thee feedback function is all the “physics” that connect proximal system output, Q.o, to the controlled input, Q.i. We usually don’t have to take all that physics into account when we model control; we just approximate it using a constant of proportionality; so the feedback function becomes k.f and the complex connection between output (Q.o) and input (Q.i) variations becomes: Q.i = k.f*Q.o

BA: He also suggests that the feedback function is the relationship between that force and nail movement and that is affected by resistance (which is not a disturbance).

RM: The relationship between hammer strike force and nail movement is just one part of the feedback function. And the feedback function is not affected at all by the resistance of the plank (as you can see by looking at the components of the causal connection between Q.o and Q.i; the resistance of the plank isn’t part of that causal chain). The resistance of the plank affects Q.i independently of the effect of Q.o.

FN: I can see how resistance to nail penetration is not a disturbance and I can remove that from the list of disturbances but what goes in the Feedback Function box?

RM: Don’t ever change;-) Certainly don’t delete “resistance to nail penetration” from the list of disturbances. It’s a great example of a disturbance.

RM: I suppose you could change the labeling of the Feedback Function to read “Effect of hammer swings on height of nail head” since you are considering output, Q.o, to be hammer swings. It’s fine to label the output that way. This is obviously a very simplified diagram of what’s involved in the behavior “hammering a nail” (a true model would involve control of several different hierarchically related variables and, as Bruce A. mentioned, the swing itself would be one of those controlled variables). I think the goal of the diagram is to capture the essential elements of the the behavior in a single control loop. This is what we do when we draw a control diagram of a tracking task, for example. We say the output is “mouse movement” even though mouse movements are themselves a controlled consequence of muscle tension variations.

RM: So I would say that your diagram is now in great shape except, possibly, for the suggested change in the description of the Feedback Function.

Best

Rick


Richard S. Marken

www.mindreadings.com
Author of Doing Research on Purpose.
Now available from Amazon or Barnes & Noble

how about distance nail moves

image0044.png

···

On Sun, Nov 15, 2015 at 5:08 AM, Fred Nickols fred@nickols.us wrote:

[From Fred Nickols (2015.11.15.0605)]

Bruce Abbott says that the force with which the hammer strikes the nail head is Qo, not the feedback function. He also suggests that the feedback function is the relationship between that force and nail movement and that is affected by resistance (which is not a disturbance). I can see how resistance to nail penetration is not a disturbance and I can remove that from the list of disturbances but what goes in the Feedback Function box?

Fred Nickols

From: Bruce Abbott [mailto:bbabbott@frontier.com]
Sent: Saturday, November 14, 2015 7:00 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

I am most interested in any comments about the Feedback Function. Do I have that right?

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.

[From Fred Nickols (2015.11.15.1550)]

I was thinking about “Changes in height of nail head�

Fred Nickols

image0044.png

···

From: Bob Hintz [mailto:bob.hintz@gmail.com]
Sent: Sunday, November 15, 2015 3:34 PM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

how about distance nail moves

On Sun, Nov 15, 2015 at 5:08 AM, Fred Nickols fred@nickols.us wrote:

[From Fred Nickols (2015.11.15.0605)]

Bruce Abbott says that the force with which the hammer strikes the nail head is Qo, not the feedback function. He also suggests that the feedback function is the relationship between that force and nail movement and that is affected by resistance (which is not a disturbance). I can see how resistance to nail penetration is not a disturbance and I can remove that from the list of disturbances but what goes in the Feedback Function box?

Fred Nickols

From: Bruce Abbott [mailto:bbabbott@frontier.com]
Sent: Saturday, November 14, 2015 7:00 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

I am most interested in any comments about the Feedback Function. Do I have that right?

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.

[From Fred Nickols (2015.11.15.1815)]

I know, I’m responding to my own post.

Here’s the problem I’m having.

The Feedback Function, as I understand it, is how my output (Qo) is connected or linked to the controlled variable (Qi).

Ordinarily, I would consider “feedback� to be changes in the height of the nail head. I hit the nail with the hammer and it moves down (or doesn’t as the case may be).

However, I’m thinking the “Feedback Function� in the formal PCT model is something else; namely, how Qo and Qi are connected or linked.

My swinging of the hammer and the height of the nail head are connected by virtue of the force of my swing and the accuracy of that swing (the arc Bruce Abbott mentioned).

So what do I put in the “Feedback Function� box? Is it “change in height of nail� or is it “downward force on nail exerted by hammer� or is it ??? “Effect of hammer swings on height of nail head� as suggested by Rick seems right but, at the same time, why not just say “changes in height of nail head� or as Bob Hintz suggested, “distance nail moves�?

Fred Nickols

image0044.png

···

From: Fred Nickols [mailto:fred@nickols.us]
Sent: Sunday, November 15, 2015 3:49 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Fred Nickols (2015.11.15.1550)]

I was thinking about “Changes in height of nail head�

Fred Nickols

From: Bob Hintz [mailto:bob.hintz@gmail.com]
Sent: Sunday, November 15, 2015 3:34 PM
To: csgnet@lists.illinois.edu
Subject: Re: [Attachment Removed] Revised Hammer and Nail Model

how about distance nail moves

On Sun, Nov 15, 2015 at 5:08 AM, Fred Nickols fred@nickols.us wrote:

[From Fred Nickols (2015.11.15.0605)]

Bruce Abbott says that the force with which the hammer strikes the nail head is Qo, not the feedback function. He also suggests that the feedback function is the relationship between that force and nail movement and that is affected by resistance (which is not a disturbance). I can see how resistance to nail penetration is not a disturbance and I can remove that from the list of disturbances but what goes in the Feedback Function box?

Fred Nickols

From: Bruce Abbott [mailto:bbabbott@frontier.com]
Sent: Saturday, November 14, 2015 7:00 PM
To: csgnet@lists.illinois.edu
Subject: RE: [Attachment Removed] Revised Hammer and Nail Model

[From Bruce Abbott (2015.11.14.1900 EST]

Fred Nickols (2015.11.14.0815) –

I am most interested in any comments about the Feedback Function. Do I have that right?

No, the force of the hammer hitting the nail head is Qo. The feedback function is the relationship between that force and nail movement. That relationship depends on the resistance of the planks to nail penetration, which determines the force required to get the nail moving into the wood. This resistance is not a disturbance but an environmental constant. The other factors you list as disturbances influence this resistance, but they are not likely to be changing while you are hammering a particular nail.

I’m not sure what you might list as disturbances. Whatever they are, they would have to affect the height of the nail (independently of the hammer blows) as this is the controlled variable in your example.

If you were seating the nail with a press, then you might vary the force exerted on the nail head to control the rate of nail penetration. This force might be set proportional to the error between nail height and nail-height reference. As the error approached zero, the force being generated by the press would decrease, reaching zero when the head was flush with the board.

Hammering is a different situation, of course, in that the force is generated only briefly with each blow. The distance the nail is driven will depend on the size of that force and the board’s resistance to nail penetration. Usually one blow will not be sufficient to seat the nail, so the process must be repeated until that condition is reached.

As I’m sure you know, the process of driving nails with a hammer requires the control of several variables. The hammer must be swung in an arc that terminates with the head of the hammer close to being centered on the nail head. The direction of the arc must be controlled so that the force applied to the nail head is directed along the axis of the nail, lest the nail be bent or its angle changed. The hammer must be raised some distance above the nail head before the blow is struck and then lowered with force. Thus a detailed scientific description of hammering would have to include all these control systems and the sequencing of the actions. But for your purposes the simplified version you present is probably adequate.

Bruce A.