Fractor

Roger wrote:

It looks remarkably like a hoax to me.  I've never seen them (but who
has seen everything?).  But the part about it supplying both the P and D
functions, and the fact that the author seemed to be claiming that the
integral term is there to supply phase shift (It isn't.  It's the
infinite DC gain you want; the phase shift is an unwanted side effect).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:

Check it again. I hope I correctly characterized your opinion.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Jerry Avins wrote:

Oh Jerry, it's late in the day, and I can't handle anything resembling
obscurity.  I don't see anything to your response except for the one
sentence above.  Be kind, and clarify.

I did a whois on the URL.  It exists, but the contact email is for an
undergraduate at the University of North Dakota.  URLs are cheap enough
to get one just for a joke.

Unless you've seen something like this before, _I_ still think it's a
hoax, or at best someone who's severely optimistic about the uniqueness
and utility of what they've found.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:

   ...


Did you check http://en.wikipedia.org/wiki/Fractor  again? I edited the
page and used your name in vain. I just wanted you to know.

   ...

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Jerry Avins wrote:

I did look -- your edits hadn't made it to the page when I posted my
reply.  Your comment is much clearer, now.

Incidentally, I cannot legally call myself an "engineer", at least for
business purposes.  A PE license is a grand thing for folks who do
different work than me, but I rarely work at the intersection of
regulations and technology.  Its lack doesn't bar me from very many
things that I'd like to do, and from nothing that I consider my core
business.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

If it IS a hoax (and the Wikipedia entry doesn't make any sense to me
too), rather than just nonsense, then it also made it to here:
<http://mechatronics.ece.usu.edu/foc/event/Fractional%20Order%20Calculu
s%20Day%20at%20Utah%20State%20University.htm>
"12:00-13:00 Gary Bohannan. @Engr203“Introducing a New Class of
Electronic Circuit Element: the Fractor” Invited Lecture for ECE6800
Electrical Engineering Colloquium
http://www.engineering.usu.edu/classes/ece/6800/"
and here:
<http://mechatronics.ece.usu.edu/foc/event/Fractional%20Order%20Calculu
Perhaps someone should ask Dr. Gary Bohannan of Wavelength Electronics,
Montana? (Resume on slide-29, here:
<http://mechatronics.ece.usu.edu/foc/event/FOC_Day@USU/foc-day@usu-welc
ome.pdf>)

Kelvin B. Hales
Kelvin Hales Associates Limited
Consulting Process Control Engineers
Web: www.khace.com

On reflection I am beginning to wonder if the problem is in the
classification "Electronic component". It maybe that from a
mathematical viewpoint you could have a systems "building block" (such
as a summing amplifier, multiplier etc) that has certain
characteristics and could be considere from a systems viewpoint as a
component.

So you could make a component that implements the function, but
conventional terminology would make that a "module" or an "integrated
circuit" rather than an "Electronic component".

Looking at the history of the article I note that the other
contributions of the original author suggest that he is more
orientated towards applied mathematics than pratical electronic
engineering, so possible confusion is perhaps understandable.

Even so, it would be a bit of a grey area. For example, ready made
snubbers are sold as individual components, allthougth in this case
Wikipedia (and textbooks) treat them as electronic circuits.

proclaimed to the world:


I had thought something similar about this but had not looked at the
guys history. His comment about it being mainly used by control
engineers, something about the way it was worded, lead me to this. I
think you might has the right idea.

On Wed, 06 Jun 2007 10:26:11 +0100, Kelvin Hales wrote:


Well, they certainly believe it's true.  The one presentation I found
looked quite opaque -- if it's truly useful stuff I sincerely hope someone
makes it a bit more accessible!  In the mean time, I think I'll stick with
traditional methods.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:

Whatever they believe, "The continuous nature of the differintegral
allows a control systems designer to select an arbitrary phase angle of
the response of their systems" is nonsense.

Moreover, "Before the invention of the fractor, control systems
designers were required to scale a 90 degree phase lag with a 90 degree
phase lead, in what is commonly known as a PID controller. The fractor
replaces the ID (integer/derivative) terms of the PID with a single F
term of the desired phase" shows a complete lack of comprehension of
what a PID is all about.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

Jerry Avins wrote:

There seems to be an unfortunate tendency in western culture to seize
upon alternative control strategies such as fuzzy logic, neural nets,
and now this, then blow it out of proportion.

I remember when fuzzy logic was billed as the answer to _every_ control
problem that you could possibly want to solve, at roughly the same time
that neural networks were billed as the solution to every problem in
both control _and_ signal processing.  It was getting so you couldn't
read an article on either of those subjects without getting virtual
spittle on your face from the wild-eyed enthusiasm of the writer.

As a consequence a lot of people shut a big iron door in the face of
anyone who mentions either of these two subjects -- in spite of the fact
that for some applications, fuzzy logic is a very successful design
strategy, and there are even a few people who not only make money with
neural nets, but make money for their customers, too (really!  I know
one of them!).

I'm wondering if this subject isn't going to wend the same path, with
people who know the subject but are completely ignorant of traditional
control feeling proud of themselves for presenting lame solutions to
well-known (and far better solved) problems of traditional control.
Should it happen, they'll alienate their audience the same way the fuzzy
logic & neural network guys did.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Frankly, I'll believe it when I see it, or more accurately, when I can buy
one.

--
Scott
Reverse name to reply

Tim Wescott wrote:

   ...


Without P.E., we can't advertise to do engineering for hire. We are
engineers, and we can say so in this context. At least where I live.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

proclaimed to the world:


It does to me too.  I thought that it might be describing something I
have seen to correct power factor in power generation but after
reading the whole thing and the mention of PID makes me think that
this information is not accurate or a hoax.

"Paul M" <PaulMatWiredogdotcom> kirjoitti
viestissä:5ghc63t4kc559s32rpn9eiue830t51i2mr@4ax.com...

The term fractor comes from application of fractional order calculus to
control systems, see

http://mechatronics.ece.usu.edu/foc/event/IEEE_meeting_SanDiego_Igor.pdf

Juhani Henttonen

Juhani Henttonen wrote:

It is not a component you can order from a catalog and solder into a
circuit. It can not allow the designer to specify an arbitrary phase
shift. The device described is either a hoax or a deranged fantasy.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯