How to convert symbolic expressions to transfer functions
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Qian Feng
am 31 Okt. 2016
Kommentiert: Walter Roberson
am 7 Aug. 2023
I am encountering the problem of converting a symbolic expression to become a transfer function. Specifically, the linear system I am dealing with contains a non-constant distributed delay term which requires performing an integration to obtain the corresponding transfer function. However, it seems that the integration operator int cannot be applied with tf variables directly.
On the other hand, if there is a way to convert symbolic expressions to transfer functions, then this problem can be easily handled in symbolic setting first.
Thanks a lot
3 Kommentare
Star Strider
am 1 Nov. 2016
I suggested a similar approach yesterday. It’s apparently not a polynomial.
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Walter Roberson
am 2 Nov. 2016
12 Kommentare
Paul
am 27 Feb. 2021
Cool code. Siight mod to also handle the case when symExp is a constant.
syms s
symExp(s) = 5;
ExpFun = matlabFunction(symExp);
ExpFun = str2func(regexprep(func2str(ExpFun), '\.([/^\\*])', '$1'));
TF = tf(ExpFun(tf('s')));
TF
TF =
5
Static gain.
Weitere Antworten (2)
HyunSang Park
am 28 Mai 2018
If you're just trying to find the peak value of the bode magnitude plot, might I suggest avoid using tf altogether? the peak value is when d(G(jw))/dw = 0. You can easily find the derivative with syms, and the plug in the w to the original tf.
0 Kommentare
Murugan venkatesan
am 7 Aug. 2023
In order to analyze the bifurcation, the input impedance expression how to plot the bode graph..
1 Kommentar
Walter Roberson
am 7 Aug. 2023
I do not understand how people can use your answer to convert symbolic expressions to transfer functions? Could you show how your solution could be used for the example symExp = (s+2)/(s^2+5*s+9); ?
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