Additive Uncertainty
q
Define
q
S
o
=(I+PK)
-1
, T
o
=PK(I+PK)
-1
S
i
=(I+KP)
-1
, T
i
=KP(I+KP)
-1
q
q
Let
P
={P+W
1
D
W
2
:
D
Î
RH
¥
}
and
let
K
stabilize
P
. Then the
closed-loop system is well-
posed and internally stable for
all ||
D
||
¥
<1 if and only if
||
W
2
KS
o
W
1
||
¥
£
1.
•