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Thread Subject:
urgent: PID controller state space or num/den representation

Subject: urgent: PID controller state space or num/den representation

From: sekai

Date: 23 Apr, 2003 11:13:48

Message: 1 of 4

hi,

I'm just a little new to advanced techniques used in control so my
question might seem a little strange for some of you :-).....

How to transorm idustrial PID controller with known P,I,D settings to
it's state space form (A,B,C,D) matrices or to [num,den] polynomial
coefficients that can be used in Matlab simulations, I mean:

industrial controler PID with known (p,i,d) values
=
(A,B,C,D) or
=
[num,den] used in Matlab environment

thanks for any suggestions or literature links that can help.

best regards
Maciej D.

Subject: urgent: PID controller state space or num/den representation

From: bv

Date: 25 Apr, 2003 17:13:31

Message: 2 of 4

sekai wrote:
>
> How to transorm idustrial PID controller with known P,I,D settings to
> it's state space form (A,B,C,D) matrices or to [num,den] polynomial
> coefficients that can be used in Matlab simulations, I mean:
>
> industrial controler PID with known (p,i,d) values
> =
> (A,B,C,D) or
> =
> [num,den] used in Matlab environment
>

There's nothing magical about PID controller; its implementation however
is a different matter. What you see are the gains for the corresponding
components of the controller,

y/u = P + I/s + D*s

The transfer fcn is not proper (acasual system), hence the state space
realization doesn't exist. The problem in (classical) implementation is
the differentiator; a washout filter - s/(tau*s+1) - is typically used
in trying to improve on the BDF approach.

--
Dr.B.Voh
------------------------------------------------------
Applied Algorithms http://sdynamix.com

Subject: urgent: PID controller state space or num/den representation

From: Vihangkumar

Date: 18 Jan, 2011 08:44:05

Message: 3 of 4

bv <bvoh@Xsdynamix.com> wrote in message <3EA9CF2B.3A8F51D4@Xsdynamix.com>...
> sekai wrote:
> >
> > How to transorm idustrial PID controller with known P,I,D settings to
> > it's state space form (A,B,C,D) matrices or to [num,den] polynomial
> > coefficients that can be used in Matlab simulations, I mean:
> >
> > industrial controler PID with known (p,i,d) values
> > =
> > (A,B,C,D) or
> > =
> > [num,den] used in Matlab environment
> >
>
> There's nothing magical about PID controller; its implementation however
> is a different matter. What you see are the gains for the corresponding
> components of the controller,
>
> y/u = P + I/s + D*s
>
> The transfer fcn is not proper (acasual system), hence the state space
> realization doesn't exist. The problem in (classical) implementation is
> the differentiator; a washout filter - s/(tau*s+1) - is typically used
> in trying to improve on the BDF approach.
>
> --
> Dr.B.Voh
> ------------------------------------------------------
> Applied Algorithms http://sdynamix.com
>
I am alos looking for PID by State Space approach,does anyone know about this?

Thanks,
V.V.Naik

Subject: urgent: PID controller state space or num/den representation

From: Arkadiy Turevskiy

Date: 18 Jan, 2011 21:43:07

Message: 4 of 4

>>kp=1;
>>ki=2;
>>kd=3;
>>controller=pid(ki,kp,kd)
>>controller_tf=tf(controller)
>>controller_ss=ss(controller)

HTH
Arkadiy

"sekai" <sekai@interia.pl> wrote in message <b85lnn$p48$2@atlantis.news.tpi.pl>...
> hi,
>
> I'm just a little new to advanced techniques used in control so my
> question might seem a little strange for some of you :-).....
>
> How to transorm idustrial PID controller with known P,I,D settings to
> it's state space form (A,B,C,D) matrices or to [num,den] polynomial
> coefficients that can be used in Matlab simulations, I mean:
>
> industrial controler PID with known (p,i,d) values
> =
> (A,B,C,D) or
> =
> [num,den] used in Matlab environment
>
> thanks for any suggestions or literature links that can help.
>
> best regards
> Maciej D.
>
>

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