Transfer function vs. gains, differentiator, integrator = different, but I don't know why?

6 views (last 30 days)
Hi,
I'm really confused why the two systems shown in the picture below give different outputs. I thought they were mathematically equivalent but give different outputs.
Please could someone show me where I have gone wrong!
Many thanks,
Peter

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 27 Dec 2011
It must be due to the limitation of calculating du/dt. If you are using all the default setting, you'll notice some warning message in the Command Window regarding step size.
There is no perfect way of calculating the theoretical du/dt in numerical simulation. Doing the du/dt first and then the integration is the problem. If you move the two integrators ahead of the du/dt block (right after the negative feedback summation block), you'll find that the results match perfectly.
  3 Comments

Sign in to comment.

More Answers (0)

Products

Community Treasure Hunt

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

Start Hunting!