Transfer function with time delay, transcendental transfer function

Question

August 2014-11-11

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https://ww2.mathworks.cn/matlabcentral/answers/162244-transfer-function-with-time-delay-transcendental-transfer-function

评论： August 2015-6-24

Question: How to define the transfer function

in Matlab?

where

s: is the laplace variable

z: is a spatial variable (also a constant here)

k1,k2,w: are constants

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Answer 1

MA 2014-11-13

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在 MATLAB Online 中打开

clear all
close all
clc;
k1=1;k2=1;w=.5;z=2;
s=tf('s');
H = (-(((s^2)+(k1+k2)*s)/(w*(s+k2)))*z);
bode(H)
grid on

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August 2014-11-13

there is the "exp" missing like:

H = exp(-(((s^2)+(k1+k2)*s)/(w*(s+k2)))*z);

but then matlab answers:

??? Error using ==> tf.exp at 31 The input argument of the "lti/exp" command must be a transfer function of the form -M*s.

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Answer 2

milad karimshoushtari 2015-5-4

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I have the same problem, did you find any answer?

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August 2015-5-5

unfortunately not until now

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Answer 3

milad karimshoushtari 2015-6-23

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I found a solution for a similar problem, you can not define this transfer function in matlab or simulink. use the time domain equation with derivatives that resulted to this transfer function, then use finite deference method to approximate the derivative of spatial variable then you can write a recursive code in matlab or in s-func simulink to solve it, it is not easy! search for finite deference method to solve spatial dependent differential equations then you will figure out the rest.