National Instruments 370757C-01 Manual De Usuario

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Chapter 2
Robustness Analysis
2-10
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Figure 2-6.  Performance Degradation of the SISO Tracking System
Advanced Topics
This section describes the theoretical background on robustness analysis 
and performance degradation.
Stability Margin
This section discusses advanced aspects of computing the stability margin 
and the related scaling algorithms.
Stability Margin and Structured Singular Values 
(μ) 
The stability margin was first defined by Safonov in [Saf82]. If you let
then you can express the margin at frequency d as
M
H
qr
diagonal l
1
w
( ) ...,l
k
w
( )
,
(
)
=
margin
ω
( )
max
=
α det I MΔ
(
) 0
{