Stability
with Structured Uncertainties
qAssume D(s)=diag[d1Ir1, …, dsIrs, D1, …, DF] Î RH¥ with ||di||¥<1 and ||Dj||¥<1.
Robust Stability Û The interconnection is stable.
•
qStability Conditions:
(1) (sufficient
condition) ||M11||¥ £1
Conservative: ignoring
structure of D(s).
(2)
(necessary conditions ) Test for each di (Dj) individually (assuming no uncertainty in other
channels): ||(M11 )ii ||¥ £1
Optimistic: ignoring
interaction between the di (Dj).
