Gap metric and Vinnicombe (nu-gap) metric for distance between two systems
[
computes the gap and Vinnicombe (ν-gap) metrics for the distance between
dynamic systems gap
,nugap
] = gapmetric(P1,P2
)P1
and P2
. The gap metric values
satisfy 0 ≤ nugap
≤ gap
≤ 1. Values close to zero imply that any controller that stabilizes
P1
also stabilizes P2
with similar closed-loop
gains.
[1] Zhou, K., Doyle, J.C., Essentials of Robust Control. London, UK: Pearson, 1997.