Multiplicative 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
={(I+W
1
D
W
2
)P:
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
T
o
W
1
||
¥
£
1.
•