How to make transfer function if you know input/output data

Question

Leon 2012-9-2

2
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/47212-how-to-make-transfer-function-if-you-know-input-output-data

Hello!

So here's the thing, I have 3 matrices, the first one contains input data to the system, the second contains output data of the system and the third one has time data.

System is SISO.

How can I get transfer function out of this data in Laplace space

{F(s)=O(s)/I(s)} O(s)=output function I(s)=input function

And identification with methods like ARX, ARMAX, RARX,..... is not allowed.

Thank you!

L.

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Answer 1

Rajiv Singh 2012-9-7

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https://ww2.mathworks.cn/matlabcentral/answers/47212-how-to-make-transfer-function-if-you-know-input-output-data#answer_58230

编辑：Rajiv Singh 2012-9-7

Have you tried tfest?

http://www.mathworks.com/help/ident/ref/tfest.html

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Answer 2

Azzi Abdelmalek 2012-9-2

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/47212-how-to-make-transfer-function-if-you-know-input-output-data#answer_57697

在 MATLAB Online 中打开

%try this function

http://www.mathworks.com/matlabcentral/fileexchange/37631-identification-by-least-square-method

[N,D]=mcar(u,y,n,k1,k2) ; %N,D disret transfer function 
ts=t(2)-t(1)  %your sample time
modeld=tf(N,D,ts)
modelc=d2c(modeld) %contiuous transfer function
[Nc,Dc]=tfdata(modelc);