Graphics Programs Reference
In-Depth Information
homogeneous solution (i.e.,
w
=
0
) to this linear system, assuming known
initial condition
x ()
at time
t 0
, has the form
x () Φ t
=
(
–
) x t t 0
(
–
)
(9.27)
0
The matrix
Φ
is known as the state transition matrix, or fundamental matrix,
and is equal to
e A t t 0
(
–
)
Φ t
(
–
)
=
(9.28)
0
Eq. (9.28) can be expressed in series format as
IA t A 2 t 2
2!
t k
k !
e A ()
++ + A k
-----
----
Φ t
(
–
)
=
=
=
(9.29)
0
t 0
=
0
k
=
0
Example:
Compute the state transition matrix for an LTI system when
01
0.5
A
=
–
–
1
Solution:
The state transition matrix can be computed using Eq. (9.29). For this pur-
pose, compute
A 2
A 3
and
. It follows
1
---
1
---
1
---
–
–
1
A 2
A 3
=
=
1
---
1
---
1
---
–
0
Therefore,
1
1
1
--- t 2
2!
--- t 3
3!
--- t 3
3!
t 2
2!
10 t
+
–
-------
++
------- …
0
+
t
–
-----
++
------- …
Φ
=
1
1
1
--- t 2
2!
--- t 3
3!
--- t 2
2!
0 t 3
3!
1
--- t
0
–
+
-------
–
------- …
+
1
–
t
+++
-------
------- …
The state transition matrix has the following properties (the proof is left as
an exercise):
Derivative property
1.
 
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