Simulink add Transferfunction as binominal equation

Hello,

Could you guide me on how to create a custom transfer function within a Simulink block?

I prefer not to expand each parameter individually.

Ideally, I am looking to implement a function similar to a binomial expression. For instance:

TF = p(1) / (1 + p(2)*s)^p(3)

Or, specifically:

TF = p(1) / (1 + p(2)*s)^3

Answer 1

[Sam Chak]

Hi @Gunnar Schmidt

Technically, if the parameters do not change during the simulation in Simulink, then the Zero-Pole block should achieve what you are looking for because the denominator contains only repeated poles.

Edit: The zpk() function in the MATLAB Function block doesn't work.

[Paul]

The zero-pole block is a very good idea. The poles are obviously at -1/p(2), but keep in mind that the gain k is not p(1). The gain needs to be adjusted to k = p(1)/p(2)^p(3) (I think).

How can the zpk command be used in a Matlab Function to implement this model?

[Sam Chak]

Hi @Paul, thanks for enlightening me on the zpk(). I didn't think this through. Your proposed LTI System block should work nicely. I admit that I rarely explore the blocks in the Control System Toolbox library.

Answer 2

[Paul]

Hi Gunnar,

You can use the LTI System block and enter as the block parameter: p(1)*tf(1,[p(2) 1])^p(3)

assuming that only the denominator is raised to the power p(3) as shown in the question.