05-03-2003, 09:00 AM
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Editor Emeritus
Join Date: Sep 2006
Posts: 3,060
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Software That Does...What?
Every now and then I come across a Pocket PC application whose description is so self-explanatory that I feel compelled to try it out. I'll let this description of Lisa for PocketPC 2002 by Poliplus Software speak for itself:
"Lisa is a "classical Feedback Control Systems" application designed to handle typical calculations in the 's' and 't' domains...Lisa supports Bode Analysis and Design, Root Locus Analysis and Design and Time analysis."
Features include:
� Line approximation for phase and magnitude plots that allows users to adjust an existing transfer function or completely design one from scratch.
� Line approximation of root locus allowing the user to drag, add or delete poles and zeros and instantly see a line approximation sketch featuring : poles, zeros, asymptotes, angles of arrival and departure, real axis points and breakaway points.
� Provides symbolic functions for Laplace transform and its inverse. This allows users to modify time equations and see its effect in the frequency domain or vice-versa.
I guess my only remaining question is: HUH?
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05-03-2003, 09:36 AM
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Ponderer
Join Date: Aug 2002
Posts: 68
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Looks like some advanced calculus to me - s and t are variables speed and time. while line approx. are used to predict where a curve (a graph) will go at some point; for example, if you know what it looks like from 1 to 4 seconds, line approx. will estimate what it looks like at 5 seconds using a form of oiler's method. What the bullet points are referring to then is the ability to create graphs through existing functions, or (as the second bullet indicates) by adding or deleting "dots." Zeros are where the function intercepts the x-axis, you all know what asymtotes are, and angle of departure and arrival indicate the angle at which the curve hits its ending and beggining.
The last bullet point is referring to the ability to change the variable of time to see its effects on the x-axis "domain" of the graph.
Basically, its a specialized graphing calculator.
:wink: And I should know, because I have an exam on this on Thursday :evil:
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05-03-2003, 10:53 AM
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Ponderer
Join Date: Jul 2003
Posts: 83
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Hi Conrad,
Just a small correction, I think the s-domain refers to the Laplace transform. And the t-domain probably refers to the time domain.
I wouldn't like you to fail your exam :wink:
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05-03-2003, 11:39 AM
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Ponderer
Join Date: Nov 2002
Posts: 86
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Feedback control systems is a subject matter usually taken up in electrical engineering, but has applications in other fields as well.
Suppose we have a system that controls something, say, a cruise control system. For this particular system, we'd be interested in a number of things, like:
* how fast the system adjusts your car to be running at the correct speed, or
* how far off your actual speed is from the value that you have set, or
* whether the car actually reaches the target speed, or does it just speed up, then slow down, then speed up, then slow down, but never hitting the mark exactly.
You can actually predict these and other system properties by making a mathematical model and running it through some evaluations, or "tests". These "tests" are the root locus, Nyquist plots and Bode plots, among others. What is usually done is to plot these graphs and judge system performance from the shape of the plot. These things are exactly what this piece of software helps you to do. 
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05-03-2003, 01:33 PM
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Sage
Join Date: Mar 2004
Posts: 734
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Quote:
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Looks like some advanced calculus to me - s and t are variables speed and time. while line approx. are used to predict where a curve (a graph) will go at some point; for example, if you know what it looks like from 1 to 4 seconds, line approx. will estimate what it looks like at 5 seconds using a form of oiler's method. What the bullet points are referring to then is the ability to create graphs through existing functions, or (as the second bullet indicates) by adding or deleting "dots." Zeros are where the function intercepts the x-axis, you all know what asymtotes are, and angle of departure and arrival indicate the angle at which the curve hits its ending and beggining.
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Or, as he said:
See, now this I understand..
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You can actually predict these and other system properties by making a mathematical model and running it through some evaluations, or "tests". These "tests" are the root locus, Nyquist plots and Bode plots, among others. What is usually done is to plot these graphs and judge system performance from the shape of the plot. These things are exactly what this piece of software helps you to do.
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Uh huh. Im sure this is the best piece of software in its category :lol:
Probably the only one in that category too 8O
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05-03-2003, 01:34 PM
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Pupil
Join Date: Aug 2002
Posts: 38
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It's written in Java -- no wonder I don't understand it!
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05-03-2003, 01:39 PM
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Contributing Editor Emeritus
Join Date: Aug 2006
Posts: 8,228
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Quote:
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Originally Posted by Joff
Hi Conrad,
Just a small correction, I think the s-domain refers to the Laplace transform. And the t-domain probably refers to the time domain.
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You beat me to the punch Joff. That is exactly what I was going to say. Really!
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05-03-2003, 03:13 PM
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Pupil
Join Date: Oct 2002
Posts: 33
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I really don't think any of that matter, considering it will probably run entirely too slow for anyone to use. (looks to be based on Formulae 1, which was SLOOOW, slow like doom2 on a ps/2)
__________________
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Glis
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05-03-2003, 04:00 PM
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Ponderer
Join Date: Feb 2003
Posts: 98
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Quote:
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Originally Posted by rave
Feedback control systems is a subject matter usually taken up in electrical engineering, but has applications in other fields as well.
Suppose we have a system that controls something, say, a cruise control system. For this particular system, we'd be interested in a number of things, like:
* how fast the system adjusts your car to be running at the correct speed, or
* how far off your actual speed is from the value that you have set, or
* whether the car actually reaches the target speed, or does it just speed up, then slow down, then speed up, then slow down, but never hitting the mark exactly.
You can actually predict these and other system properties by making a mathematical model and running it through some evaluations, or "tests". These "tests" are the root locus, Nyquist plots and Bode plots, among others. What is usually done is to plot these graphs and judge system performance from the shape of the plot. These things are exactly what this piece of software helps you to do. |
Well, duh!
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05-03-2003, 04:07 PM
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Theorist
Join Date: Sep 2006
Posts: 307
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Well, FINALLY! This is probably the KILLER APP I've been waiting for! This, and something for me to track my biorhythms.
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Linear Mode
