Conversion from multivariable ARX model to multivariable State-Space model using MATLAB


Does MATLAB convert MIMO ARX model to MIMO State-Space model (and vice versa)? If yes, what is the command? I am not able to find it. I am currently using (R13) Service Pack 1.

Thanks a lot!


Reply to
Loading thread data ...

If I understand your needs right, you have a model of a MIMO system in the format


and you would like to find an equivalent state-space model

xdot(k) = Ax(k)+Bu(k) y(k) = Cx(k)+Du(k)

what you need is a routine for conversion between polynomial matrix fraction D^-1N and state-space format. As far as I know, there is none in Control System Toolbox for Matlab. This routine is included in a commercial Polynomial Toolbox distributed by

formatting link
You can also check if it is included in the Slicot library at
formatting link
Some functionality for polynomial matrices is also covered in Scilab, as far as I know.

In Polynomial Toolbox, the typical session looks like this:

A = -0.64 - 0.56d + 0.44d^2 -0.95 + 0.78d + 0.57d^2 -0.82 - 0.27d - 1.2d^2 -2.2 + 0.99d - 0.52d^2 B = 0.23 + 0.021d -1 - 0.95d

a = x1 x2 x3 x4 x1 -1.583 1 1.266 0 x2 3.401 0 2.82 0 x3 0.4702 0 -0.02444 1 x4 -1.808 0 -1.288 0 b = u1 x1 3.926 x2 -4.29 x3 -0.1479 x4 2.565 c = x1 x2 x3 x4 y1 1 0 0 0 y2 -0 0 1 0 d = u1 y1 -2.374 y2 1.341 Sampling time: 1 Discrete-time model.

Best regards, Zdenek

Reply to
Zdeněk Hurá

Hi Zdenek,

Thanks a lot for your help!!!!! I really appreciate it ^__^



Zdenek Hur=E1k wrote:

Reply to

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.