Prev: Read String To Structure
Next: Help needed
From: Alexandre Campeau on 21 Jun 2010 15:28
Hi,

I am trying to do a discrete simulation but I have a very big problem: the discrete result is very far from the continuous one. I did a lot of Simulink in the past, including discrete representation and I never encountered such a problem.

Here is the Simulink model
http://www.angelfire.com/al4/lekours/ContinuousDiscrete.png
http://www.angelfire.com/al4/lekours/ContinuousDiscrete.mdl

The first system is the continuous one.
The second system is the same as the first one but I added rate transition for a gain.
This little modification has a big consequence on the result and it should not...
The third one is an all discrete representation.

When I simulate the system with transfer function, it works, even in discrete or with delays.
However, I can't use transfer function, I have to use this representation.

Thank you very much for your help !

Alex
From: Jean Baptiste Lanfrey on 22 Jun 2010 07:30
You can get rid of the derivative block and use the signal in between the
two integrators.


"Alexandre Campeau" <lekours4(a)hotmail.com> a �crit dans le message de news:
hvoegm$b3j$1(a)fred.mathworks.com...
> Hi,
>
> I am trying to do a discrete simulation but I have a very big problem: the
> discrete result is very far from the continuous one. I did a lot of
> Simulink in the past, including discrete representation and I never
> encountered such a problem.
>
> Here is the Simulink model
> http://www.angelfire.com/al4/lekours/ContinuousDiscrete.png
> http://www.angelfire.com/al4/lekours/ContinuousDiscrete.mdl
>
> The first system is the continuous one.
> The second system is the same as the first one but I added rate transition
> for a gain. This little modification has a big consequence on the result
> and it should not...
> The third one is an all discrete representation.
>
> When I simulate the system with transfer function, it works, even in
> discrete or with delays.
> However, I can't use transfer function, I have to use this representation.
>
> Thank you very much for your help !
>
> Alex


 | 
Pages: 1
Prev: Read String To Structure
Next: Help needed