Create an options set for a robstab, robgain, or musynperf calculation that displays the progress of the underlying mussv calculation. Also, turn on the element-by-element sensitivity calculation.
Specify optional
comma-separated pairs of Name,Value arguments. Name is
the argument name and Value is the corresponding value.
Name must appear inside quotes. You can specify several name and value
pair arguments in any order as
Name1,Value1,...,NameN,ValueN.
Example: 'Display','on','Sensitivity','on'
'Display' — Display progress of computation and summary report 'off' (default) | 'on'
Display progress and summary of the robustness computation,
specified as the comma-separated pair consisting of 'Display' and
one of these values:
'off' — Do not display progress
and report.
'on' — Display progress
and report. When you use this option, a progress indicator and summary
of results is displayed in the command window, similar to the following.
points completed (of 28) ... 28
System is robustly stable for the modeled uncertainty.
-- It can tolerate up to 116% of the modeled uncertainty.
-- There is a destabilizing perturbation amounting to 117% of the modeled uncertainty.
-- This perturbation causes an instability at the frequency 5.9 rad/seconds.
This setting overrides the silent ('s')
option in the MussvOptions option.
'VaryFrequency' — Compute robustness margin as function of frequency 'off' (default) | 'on'
Return robustness margin as a function of frequency, specified
as the comma-separated pair consisting of 'VaryFrequency' and
one of these values:
'off' — Only return margins
at frequencies where robustness is weakest.
'on' — Compute robustness
margins over a frequency grid suitable for plotting. The frequency
grid is chosen automatically based on system dynamics. This calculation
is done in addition to identifying the critical frequency where the
margin is weakest. Access the frequency values and corresponding margins
in the info output of robstab and robgain.
This option is ignored for ufrd and genfrd models.
Calculate the sensitivity of the robustness margin to each uncertain
element in the model, specified as the comma-separated pair consisting
of 'Sensitivity' and either 'off' or 'on'.
Each uncertain element contributes to the overall stability
margin in a coupled manner. Set this option to 'on' to
estimate the sensitivity of the margin to each element. This element-by-element
sensitivity provides an indication of which elements are most problematic
for robustness. Access the sensitivity estimates in the info output
of robstab and robgain.
'SensitivityPercent' — Percentage variation of uncertainty for computing sensitivity 25 (default) | positive scalar value
Percentage variation of uncertainty level for computing sensitivity,
specified as the comma-separated pair consisting of 'SensitivityPercent' and
a positive scalar value. The sensitivity to a particular uncertain
element is estimated using a finite difference calculation. This calculation
increases the (normalized) amount of uncertainty on this element by
some percentage, computes the resulting robustness, and computes the
ratio of percent variations. This option specifies the percentage
increase in uncertainty level applied to each element. The default
value is 25%.
'MussvOptions' — Options for mussv calculation '' (default) | character vector
Options for the underlying mussv calculation
that robstab and robgain perform,
specified as the comma-separated pair consisting of 'MussvOptions' and
a character vector such as 'sm3' or 'ad'.
Some MussvOptions values that are especially
useful for improving robustness-margin calculations include:
'a' — Force the use of LMI
optimization to compute the μ upper bound,
which yields better results in general but can be expensive when some ureal elements
are repeated multiple times.
'mN' — Use multiple restarts
when computing the μ lower bound, which corresponds
to the upper bound for robustness margins. This option can reduce
the gap between the lower bound and upper bound on the robustness
margins. N is the number of restarts. For example,
setting 'MussvOptions' to 'm3' causes
three restarts.
See mussv for the remaining
available options and corresponding characters. The default, '',
uses the default options for mussv.
opts — Options for robustness commands robOptions object
Options for robustness commands robstab, robgain,
and musynperf, returned as a
robOptions object. Use the options as
an input argument to robstab,
robgain, or
musynperf. For example:
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