transfer function of sqrt of s

20 次查看（过去 30 天）
Nicholas
Nicholas 2014-3-5
评论： Walter Roberson 2015-6-20
how can i write a simulink model where my transfer function is 1/(sqrt(s)+a) where a is just some constant.

请先登录，再回答此问题。

回答（2 个）

Mike Borrello
Mike Borrello 2014-4-29
But wait ... mathematically it is possible! The transfer function is indeed valid! I assume this transfer function was derived from an assumed infinite element network model. The issue is implementation. You need to approximate the square root of s as a series and decide where to cutoff the series as your approximation to the square root. The expression then becomes a high order rational transfer function in s which is linear and which then can be handled by Matlab and Simulink tools.
  2 个评论
Daniel
Daniel 2015-6-20
How exactly would you approximate it? Can you please provide a sample series approximation?
Walter Roberson
Walter Roberson 2015-6-20
See http://mathwiki.ucdavis.edu/Calculus/Series/Taylor_Expansion
and be sure to read the next page in the site for the case where abs(x) > 1, which implies you would need to split into two cases, one for abs(x) <= 1 and the other for abs(x) > 1

请先登录，再进行评论。

Paul
Paul 2014-3-5
This is not possible since it's an invalid transfer function. You should be able to write the tf in terms of s^3, s^2, s etc, which is not possible in this case. Normally you would be able to calculate the tf in Matlab by doing:
s = tf('s')
TF = 1/(sqrt(s)+1)

类别

在 Help Center 和 File Exchange 中查找有关 Modeling 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by