Chapter 2 Linear System Representation
© National Instruments Corporation 2-9 Xmath Control Design Module
done internally to return A, B, C, and D, though the format of the variable
Sys itself remains unchanged. The transfer function must be proper.
Using the systems defined in Examples 2-1 and 2-2, Example 2-4
illustrates the use of abcd( ).
Example 2-4 Using abcd( ) to Extract the State-Space Matrices
H3=makepoly([2,-1],"s")/makepoly([1,6,8],"s");
sys4=system([0,1;-0.75,0],[1,0]',[0,1],0,
{dt=0.5});
You can extract the state-space matrices from each.
Note For the transfer function H3, an internal conversion is performed.
[A3,B3,C3,D3] = abcd(H3)?
A3 (a square matrix) =
-2 1.58114
0 -4
B3 (a column vector) =
0
2
C3 (a row vector) = -1.58114 1
D3 (a scalar) = 0
[A4,B4,C4,D4,X0] = abcd(sys4)
A4 (a square matrix) =
0 1
-0.75 0
B4 (a column vector) =
1
0
C4 (a row vector) = 0 1
D4 (a scalar) = 0
X0 (a column vector) =
0
0