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Topic: OutputResponse gives funny results
Replies: 1   Last Post: Oct 25, 2012 11:35 PM

 Messages: [ Previous | Next ]
 emammendes@gmail.com Posts: 143 Registered: 8/22/05
OutputResponse gives funny results
Posted: Oct 22, 2012 2:07 AM

Hello

I am trying to implement some examples on Dorf's book. Here is a code for
one of them.

Tcl[p_,Kp_,Kd_,Ki_]=TransferFunctionModel[(Ki+Kp s+Kd s^2)/(Ki+Kp s+Kd
s^2+p^2 s^2+2 p s^3+s^4),s]

fcl[t_,p_,Kp_,Kd_,Ki_]=Abs[OutputResponse[Tcl[p,Kp,Kd,Ki],UnitStep[t],t]];

Manipulate[{N[TransferFunctionPoles[Tcl[p,6,4,1]],2],Plot[fcl[t,p,6,4,1],{t,
0,Ts},PlotRange->All,AxesLabel->{t,x[t]},PlotStyle->Thickness[0.01],GridLine
s->Automatic]},Style["Example 4.4 - Dorf - 12^th Edition - R(s) = 10/s, D(s)
=
0",Bold],{{p,2},0,100,Appearance->"Labeled"},{{Ts,20},0.1,100,Appearance->"L
abeled"}]

Even though the poles are on the left side (stable system), OutResponse
gives huge numbers (instability) when the slider for the variable Ts is
moved to higher values. More than, it is seems that this simple code makes
Mathematica ever so slow.

Have I missed something?

Many thanks

Ed

Date Subject Author
10/22/12 emammendes@gmail.com
10/25/12 richard i. pelletier