Re: Book for Control 2.0.0

[Lukas Reichlin]

On 21.03.2011, at 13:50, Richard Balogh wrote:

> It would be nice, if the examples from the above mentioned "Matlab
> Compendium" 
> would work also in octave - no need to write another documentation :)
> 
> I've tried first of them (page 10, p. 16 in .pdf). 
> 
> One issue is lack of the zpk function. 
> 
> Another, probably more important is that results are different:
> 
> Matlab output: 
> 
> Transfer function:   8 / (s^2 + 30)
> A_ss_tf_ss = [  0   -7.5000 ;    4.0000         0]
> 
> Octave output:
> 
> Transfer function:  8 s^2 / ( s^4 + 30 s^2 )
> A_ss_tf_ss = [ 0    1    0    0;    0    0    1    0;    0    0    0    1;  
> -0   -0  -30   -0]
> 
> Richard Balogh

Hi Richard,

Could you please provide the m-file that you used for the transfer function? 
From the results I can't tell whether Matlab computed a minimal realization 
(zero-pole cancellation at s = 0) or Octave introduced additional pairs of 
zeros and poles.

ZPK models are not available yet. As a workaround, you can use
sys = tf (k*poly (z), poly (p))
as well as
p = pole (sys)
[z, k] = zero (sys)
Maybe I should write a wrapper for these commands.

Regards,
Lukas