Transfer function in Simulink different from Matlab

1 次查看（过去 30 天）
Daniel P
Daniel P 2012-11-20
Hey everybody,
I am plotting the step response of a transfer function with matlab and the result is fine.
Gs = (1/s^2) * (1 - 2*exp(-s*0.5) + exp(-s))
Result: http://up.picr.de/12549059jw.jpg
Now I am trying to build this function in Simulink with standard blocks, but the step response is different from matlab:
Model: http://up.picr.de/12549080vj.jpg
and
Result: http://up.picr.de/12549087ia.jpg
I have tried many different solver settings but the result is always the same. I anyone has Ideas what might be the problem, please let me know.
Thanks in advance,
Daniel.
  4 个评论
显示 2更早的评论
Azzi Abdelmalek
Azzi Abdelmalek 2012-11-21
What version of matlab are you using? this did'nt work for me

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Pedro Villena
Pedro Villena 2012-11-21
编辑：Pedro Villena 2012-11-21
Gs = (1/s^2) * (1 - 2*exp(-s*0.5) + exp(-s))
Gs = 1/s^2 - (2/s^2)*exp(-s*0.5) + (1/s^2)*exp(-s)

更多回答（1 个）

Ryan G
Ryan G 2012-11-20
The easiest way to achieve the desired results would be with the LTI System block which comes with the Control System Toolbox. This allows you to create a system in MATALB and directly utilize it in Simulink.
However, your model as shown works. You need to adjust the relative tolerance in the configuration parameters to be tighter. Try 1e-6 or 1e-8 and check the results.
  2 个评论
Daniel P
Daniel P 2012-11-20
Hello Ryan.
Are you talking about the relative tolerances of the Integrators? I have tried to reduce them to 1e-10 but still the same (bad) result.
Any other suggestions?
Thanks for your help!
Daniel P
Daniel P 2012-11-20
Using the LTI System block causes the same problem :-/

请先登录，再进行评论。

类别

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

标签

产品

Community Treasure Hunt

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

Start Hunting!

Translated by