How to implement improper transfer function (s + 0.1) in simulink?

Question

Talha Kaleem 2019-4-4

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/454305-how-to-implement-improper-transfer-function-s-0-1-in-simulink

评论： Sina Dehbari 2020-5-7

i have used the matlab guide of solving improper fractions in simulink which is as follows.

num=[1 0.1];
den=1;
[r,p,k]=residue(num,den);
sys1 = tf(r(1),[1,-p(1)])
sysk1 = k(1)*s;
sysk2 = k(2);

But it shows this error.

Solving_ImproperFun_simulink

Index exceeds the number of array elements (0).

Error in Solving_ImproperFun_simulink (line 4)

sys1 = tf(r(1),[1,-p(1)])

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2019-4-4

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/454305-how-to-implement-improper-transfer-function-s-0-1-in-simulink#answer_368991

在 MATLAB Online 中打开

Try it at the MATLAB level. You will see that r and p both come out empty, so indexing them at location 1 will not work.

Why not go directly to

sys1 = tf(num, den);

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2019-4-4

You cannot import a transfer function. You would not be able to import a transfer function even if your original code had worked.

You cannot use the Transfer Function block in Simulink for this because that block requires that the denominator be at least as high a degree as the numerator.

You can use a State Space block: https://www.mathworks.com/help/simulink/slref/statespace.html . And you can use MATLAB ahead of time to work out what the matrices should be.

You can also use tf() inside a MATLAB Function Block. It is possible that you might need to coder.external() it, and you might not be able to use it with any Rapid Acceleration turned on.

Talha Kaleem 2019-4-6

Walter. Thank you for your time.

Walter. I have tried matlab functions using coder.extrinsic but it also did't worked. I will also try the space state method to get out of problem.

On the other hand walter. I have found one other solution. Now instead of adding only (s + 1). I am adding (s + 1)/(0.0001s + 1). Because, in this case the pole is very far. Thus having almost negligible effect on system at higher frequencies.

请先登录，再进行评论。