Convert state-space representation (MIMO) to transfer function matrix

26 Nov 2020
3 Réponses
Réponse acceptée
Mise à jour 26 Nov 2020
34 Vues (30 jours)

 Réponse acceptée

Walter Roberson
Walter Roberson le 26 Nov 2020
Ran in:

0 votes

Ran in:
https://www.mathworks.com/help/matlab/ref/ss2tf.html
But if you have an existing ss system created with https://www.mathworks.com/help/control/ref/ss.html then use tf()
A = [-1.5,-2;1,0];
B = [0.5;0];
C = [0,1];
D = 0;
sys = ss(A,B,C,D)
sys = A = x1 x2 x1 -1.5 -2 x2 1 0 B = u1 x1 0.5 x2 0 C = x1 x2 y1 0 1 D = u1 y1 0 Continuous-time state-space model.
sys_as_tf = tf(sys)
sys_as_tf = 0.5 --------------- s^2 + 1.5 s + 2 Continuous-time transfer function.

Plus de réponses (2)

EMAD ALHANI
EMAD ALHANI le 26 Nov 2020

0 votes

it is giving me wrong result I would like to have only four transfer function .
>> A = [ 0 0 -0.1 0.1;
0 0 -4.6 -4.5;-0.0008 0.0008 0 0;0 -4.0 0 5.6];
B = [ 14.8 32.2;
35 -24;-0.75 -0.41;0 0];
C = [ 1 0 0 0;0 1 0 0;0 0 1 0;0 0 0 1];
D = 0;
>> sys = ss(A,B,C,D )
sys =
A =
x1 x2 x3 x4
x1 0 0 -0.1 0.1
x2 0 0 -4.6 -4.5
x3 -0.0008 0.0008 0 0
x4 0 -4 0 5.6
B =
u1 u2
x1 14.8 32.2
x2 35 -24
x3 -0.75 -0.41
x4 0 0
C =
x1 x2 x3 x4
y1 1 0 0 0
y2 0 1 0 0
y3 0 0 1 0
y4 0 0 0 1
D =
u1 u2
y1 0 0
y2 0 0
y3 0 0
y4 0 0
Continuous-time state-space model.
>> sys_as_tf = tf(sys)
sys_as_tf =
From input 1 to output...
14.8 s^3 - 82.81 s^2 - 280.8 s - 3.019
1: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
35 s^3 - 192.6 s^2 - 19.27 s - 0.2893
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-0.75 s^3 + 4.216 s^2 + 13.41 s + 0.2243
3: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-140 s^2 - 13.8 s - 0.2067
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
From input 2 to output...
32.2 s^3 - 180.3 s^2 - 570.1 s - 2.167
1: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-24 s^3 + 136.3 s^2 - 10.44 s - 0.6743
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-0.41 s^3 + 2.251 s^2 + 7.632 s + 0.456
3: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
96 s^2 - 7.544 s - 0.4817
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
Continuous-time transfer function.

1 commentaire
Afficher -1 commentaires plus anciens Masquer -1 commentaires plus anciens

Walter Roberson
Walter Roberson le 26 Nov 2020
Your D is 4 x 2. That is the configuration for 2 inputs and 4 outputs per input

Connectez-vous pour commenter.

EMAD ALHANI
EMAD ALHANI le 26 Nov 2020

0 votes

thank you.
>> A = [ 0 0 -0.1 0.1;
0 0 -4.6 -4.5;-0.0008 0.0008 0 0;0 -4.0 0 5.6];
B = [ 14.8 32.2;
35 -24;-0.75 -0.41;0 0];
C = [ 1 0 0 0;0 1 0 0;0 0 1 0;0 0 0 1];
D = 0;
>> sys = ss(A,B,C,D )
sys =
A =
x1 x2 x3 x4
x1 0 0 -0.1 0.1
x2 0 0 -4.6 -4.5
x3 -0.0008 0.0008 0 0
x4 0 -4 0 5.6
B =
u1 u2
x1 14.8 32.2
x2 35 -24
x3 -0.75 -0.41
x4 0 0
C =
x1 x2 x3 x4
y1 1 0 0 0
y2 0 1 0 0
y3 0 0 1 0
y4 0 0 0 1
D =
u1 u2
y1 0 0
y2 0 0
y3 0 0
y4 0 0
Continuous-time state-space model.
>> sys_as_tf = tf(sys)
sys_as_tf =
From input 1 to output...
14.8 s^3 - 82.81 s^2 - 280.8 s - 3.019
1: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
35 s^3 - 192.6 s^2 - 19.27 s - 0.2893
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-0.75 s^3 + 4.216 s^2 + 13.41 s + 0.2243
3: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-140 s^2 - 13.8 s - 0.2067
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
From input 2 to output...
32.2 s^3 - 180.3 s^2 - 570.1 s - 2.167
1: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-24 s^3 + 136.3 s^2 - 10.44 s - 0.6743
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
-0.41 s^3 + 2.251 s^2 + 7.632 s + 0.456
3: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
96 s^2 - 7.544 s - 0.4817
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
Continuous-time transfer function.
>> C = [ 0 0 0 0;0 0 0 0;0 0 0 0;0 0 0 1];
>> sys = ss(A,B,C,D)
sys =
A =
x1 x2 x3 x4
x1 0 0 -0.1 0.1
x2 0 0 -4.6 -4.5
x3 -0.0008 0.0008 0 0
x4 0 -4 0 5.6
B =
u1 u2
x1 14.8 32.2
x2 35 -24
x3 -0.75 -0.41
x4 0 0
C =
x1 x2 x3 x4
y1 0 0 0 0
y2 0 0 0 0
y3 0 0 0 0
y4 0 0 0 1
D =
u1 u2
y1 0 0
y2 0 0
y3 0 0
y4 0 0
Continuous-time state-space model.
>> sys_as_tf = tf(sys)
sys_as_tf =
From input 1 to output...
1: 0
2: 0
3: 0
-140 s^2 - 13.8 s - 0.2067
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
From input 2 to output...
1: 0
2: 0
3: 0
96 s^2 - 7.544 s - 0.4817
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
Continuous-time transfer function.
>> C = [ 0 0 0 0;0 1 0 0;0 0 0 0;0 0 0 1];
>> sys = ss(A,B,C,D)
sys =
A =
x1 x2 x3 x4
x1 0 0 -0.1 0.1
x2 0 0 -4.6 -4.5
x3 -0.0008 0.0008 0 0
x4 0 -4 0 5.6
B =
u1 u2
x1 14.8 32.2
x2 35 -24
x3 -0.75 -0.41
x4 0 0
C =
x1 x2 x3 x4
y1 0 0 0 0
y2 0 1 0 0
y3 0 0 0 0
y4 0 0 0 1
D =
u1 u2
y1 0 0
y2 0 0
y3 0 0
y4 0 0
Continuous-time state-space model.
>> sys_as_tf = tf(sys)
sys_as_tf =
From input 1 to output...
1: 0
35 s^3 - 192.5 s^2 - 19.27 s - 0.2893
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
3: 0
-140 s^2 - 13.8 s - 0.2067
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
From input 2 to output...
1: 0
-24 s^3 + 136.3 s^2 - 10.44 s - 0.6743
2: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912
3: 0
96 s^2 - 7.544 s - 0.4817
4: ---------------------------------------------
s^4 - 5.6 s^3 - 18 s^2 - 0.02016 s + 0.002912

Catégories

En savoir plus sur System Identification Toolbox dans Centre d'aide et File Exchange

Produits

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by