Use the TuningGoal.Poles
object to specify
a tuning requirement for constraining the closedloop dynamics of
a control system or of specific feedback loops within the control
system. You can use this requirement for control system tuning with
tuning commands, such as systune
or looptune
.
A TuningGoal.Poles
requirement can ensure a minimum
decay rate or minimum damping of the poles of the control system or
loop. The requirement can also eliminate fast dynamics in the tuned
system.
creates
a default template for constraining the closedloop pole locations.
The minimum decay rate, minimum damping constant, and maximum natural
frequency define a region of the complex plane in which poles of the
component must lie. Set Req
= TuningGoal.Poles(mindecay
,mindamping
,maxfreq
)mindecay
= 0, mindamping
=
0, or maxfreq
= Inf
to skip
any of the three constraints.
constrains
the poles of the sensitivity function measured at a specified location
in the control system. (See Req
= TuningGoal.Poles(location
,mindecay
,mindamping
,maxfreq
)getSensitivity
for information about sensitivity functions.) Use this syntax to narrow
the scope of the requirement to a particular feedback loop.
If you want to constrain the poles of the system with one or
more feedback loops opened, set the Openings
property.
To limit the enforcement of this requirement to poles having natural
frequency within a specified frequency range, set the Focus
property.
(See Properties.)

Minimum decay rate of poles of tunable component, specified as a nonnegative scalar value in the frequency units of the control system model you are tuning. When you tune the control system using this requirement, the closedloop poles of the control system are constrained to satisfy:
Set 

Desired minimum damping ratio of the closedloop poles, specified as a value between 0 and 1. Poles that depend on the tunable parameters are constrained
to satisfy Set 

Desired maximum natural frequency of closedloop poles, specified as a scalar value in the frequency units of the control system model you are tuning. Poles are constrained to satisfy Set 

Location at which poles are assessed, specified as a string
or cell array of strings. When you use this input, the requirement
constrains the poles of the sensitivity function measured at this
location. (See
If 

Minimum decay rate of closedloop poles of tunable component,
specified as a positive scalar value in the frequency units of the
control system you are tuning. The initial value of this property
is set by the When you tune the control system using this requirement, closedloop
poles are constrained to satisfy You can use dot notation to change the value of this property
after you create the requirement. For example, suppose Req.MinDecay = 0.001; Default: 0 

Desired minimum damping ratio of closedloop poles, specified
as a value between 0 and 1. The initial value of this property is
set by the Poles that depend on the tunable parameters are constrained
to satisfy Default: 0 

Desired maximum natural frequency of closedpoles, specified
as a scalar value in the frequency units of the control system model
you are tuning. The initial value of this property is set by the Poles of the block are constrained to satisfy You can use dot notation to change the value of this property
after you create the requirement. For example, suppose Req.MaxFrequency = 1000; Default: 

Frequency band in which tuning requirement is enforced, specified
as a row vector of the form Set the Req.Focus = [1,100]; Default: 

Location at which poles are assessed, specified as a string or cell array of strings that identify one or more analysispoint locations in the control system to tune. The value of the 

Models to which the tuning requirement applies, specified as a vector of indices. Use the Req.Models = 2:4; When Default: 

Feedback loops to open when evaluating the requirement, specified as a cell array of strings that identify loopopening locations. The tuning requirement is evaluated against the openloop configuration created by opening feedback loops at the locations you identify. If you are using the requirement to tune a Simulink model
of a control system, then If you are using the requirement to tune a generalized statespace
( Default: 

Name of the requirement object, specified as a string. For example, if Req.Name = 'LoopReq'; Default: 
TuningGoal.Poles
restricts the
closedloop dynamics of the tuned control system. To constrain the
dynamics or ensure the stability of a single tunable component, use TuningGoal.ControllerPoles
.
When you use a TuningGoal
object to specify
a tuning requirement, the software converts the requirement into a
normalized scalar value f(x). x is
the vector of free (tunable) parameters in the control system. The
software then adjusts the parameter values to minimize f(x),
or to drive f(x) below 1 if
the tuning requirement is a hard constraint.
For TuningGoal.Poles
, f(x)
reflects the relative satisfaction or violation of the goal. For example,
if you attempt to constrain the closedloop poles of a feedback loop
to a minimum damping of ζ = 0.5, then:
f(x) = 1 means the smallest damping among the constrained poles is ζ = 0.5 exactly.
f(x) = 1.1 means the smallest damping ζ = 0.5/1.1 = 0.45, roughly 10% less than the target.
f(x) = 0.9 means the smallest damping ζ = 0.5/0.9 = 0.55, roughly 10% better than the target.