problem while obtaing matrixes into symbolic format

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problem while obtaing matrixes into symbolic format

Beginner1
Hi,
I want to obtain the system defined by its state-space matrixes (A_ol,
B_ol,C_ol and D_ol) into symbolic format. The parameters these matrixes
depend on have specific values but in the current case I want to obtain the
A_ol, B_ol,C_ol and D_ol matrixes into symbolic. However, Octave gives an
error saying:
error: lti: set: key 'lti' requires an LTI model
error: called from
    set at line 135 column 13
    ss at line 249 column 9
    trysimbols_m at line 46 column 10

And it is a linear time invariant model. Any advice to solve this?




/*pkg load symbolic
pkg load control

syms kv Tv kq Tq kdroop_AC FSM_slope enable

 
  %Outer loop:Vdc-Q
   A_ol=[0 0;0 0];
  B_ol=[-kv/Tv kv/Tv 0 0 0 0 -kv*FSM_slope*enable/Tv kv*enable/Tv
-kv*enable/Tv kv*enable/Tv;0 0 kq/Tq -kq/Tq -(kq/Tq)*kdroop_AC
(kq/Tq)*kdroop_AC 0 0 0 0];
  C_ol=[1 0;0 1];
  D_ol=[-kv kv 0 0 0 0 -kv*FSM_slope*enable kv*enable -kv*enable kv*enable;0
0 kq -kq -kq*kdroop_AC kq*kdroop_AC 0 0 0 0];

 %Outer loop
  stname_ol = {'xv','xq'};
 
inname_ol={'vdcref','vdc','qacref','qac','vacref','vac','fmeas','pdcref','paux','FSMcoordpos'};
  outname_ol={'idref','iqref'};
  sys_ol = ss
(A_ol,B_ol,C_ol,D_ol,'stname',stname_ol,'inname',inname_ol,'outname',outname_ol);*/



 



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Re: problem while obtaing matrixes into symbolic format

Colin Macdonald-2
I suspect "ss" from the control pkg does not support symbolic inputs.


On 2018-10-03 10:13 a.m., Beginner1 wrote:

> Hi,
> I want to obtain the system defined by its state-space matrixes (A_ol,
> B_ol,C_ol and D_ol) into symbolic format. The parameters these matrixes
> depend on have specific values but in the current case I want to obtain the
> A_ol, B_ol,C_ol and D_ol matrixes into symbolic. However, Octave gives an
> error saying:
> error: lti: set: key 'lti' requires an LTI model
> error: called from
>      set at line 135 column 13
>      ss at line 249 column 9
>      trysimbols_m at line 46 column 10
>
> And it is a linear time invariant model. Any advice to solve this?
>
>
>
>
> /*pkg load symbolic
> pkg load control
>
> syms kv Tv kq Tq kdroop_AC FSM_slope enable
>
>  
>    %Outer loop:Vdc-Q
>     A_ol=[0 0;0 0];
>    B_ol=[-kv/Tv kv/Tv 0 0 0 0 -kv*FSM_slope*enable/Tv kv*enable/Tv
> -kv*enable/Tv kv*enable/Tv;0 0 kq/Tq -kq/Tq -(kq/Tq)*kdroop_AC
> (kq/Tq)*kdroop_AC 0 0 0 0];
>    C_ol=[1 0;0 1];
>    D_ol=[-kv kv 0 0 0 0 -kv*FSM_slope*enable kv*enable -kv*enable kv*enable;0
> 0 kq -kq -kq*kdroop_AC kq*kdroop_AC 0 0 0 0];
>
>   %Outer loop
>    stname_ol = {'xv','xq'};
>  
> inname_ol={'vdcref','vdc','qacref','qac','vacref','vac','fmeas','pdcref','paux','FSMcoordpos'};
>    outname_ol={'idref','iqref'};
>    sys_ol = ss
> (A_ol,B_ol,C_ol,D_ol,'stname',stname_ol,'inname',inname_ol,'outname',outname_ol);*/
>
>
>
>    
>
>
>
> --
> Sent from: http://octave.1599824.n4.nabble.com/Octave-General-f1599825.html
>
>



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Re: problem while obtaing matrixes into symbolic format

Beginner1
Okay, you are right. Octave control package and command "ss" does not support
symbolic inputs. However, my final A B C D matrixes are constructed by
connecting small Ai,Bi,Ci,Di matrixes and the final structure is quite big.
So I need to define for each subsystem a "ss" command to build the
state-space subsystem.  Any tips on how to obtain the final ABCD matrixes in
symbolic format?





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Re: problem while obtaing matrixes into symbolic format

Colin Macdonald-2
On 2018-10-04 2:27 a.m., Beginner1 wrote:
> Okay, you are right. Octave control package and command "ss" does not support
> symbolic inputs. However, my final A B C D matrixes are constructed by
> connecting small Ai,Bi,Ci,Di matrixes and the final structure is quite big.
> So I need to define for each subsystem a "ss" command to build the
> state-space subsystem.  Any tips on how to obtain the final ABCD matrixes in
> symbolic format?

Sorry I don't know anything about "ss" so cannot offer assistance with that.

Colin