Therer really isn't a need to use tf2ss anymore. The functions tf(), ss(),and zpk() can be used to convert from one form to another. In this case:
nums = {[1 -1] [1 7.5];[1 0] 6.5};
systf = tf(nums,dens)
systf =
From input 1 to output...
s - 1
1: -------------
s^2 + s + 6.5
s
2: -------------
s^2 + s + 6.5
From input 2 to output...
s + 7.5
1: -------------
s^2 + s + 6.5
6.5
2: -------------
s^2 + s + 6.5
Continuous-time transfer function.
sysss = ss(systf)
sysss =
A =
x1 x2 x3 x4
x1 -1 -3.25 0 0
x2 2 0 0 0
x3 0 0 -1 -3.25
x4 0 0 2 0
B =
u1 u2
x1 2 0
x2 0 0
x3 0 2
x4 0 0
C =
x1 x2 x3 x4
y1 0.5 -0.25 0.5 1.875
y2 0.5 0 0 1.625
D =
u1 u2
y1 0 0
y2 0 0
Continuous-time state-space model.
The matrices in the state space model can be accessed with dot indexing
sysss.A
ans =
-1.0000 -3.2500 0 0
2.0000 0 0 0
0 0 -1.0000 -3.2500
0 0 2.0000 0
Note that the result of ss() when coverting a MIMO tranfer function matrix will typically be non-minimal. In this case sysss has four states, when only two are needed.
