User`s guide

10 U s ing Identified Mo dels in Contr ol Design
Note The syntax sis otoo l(model('m')) is e quivalent to
sisotool(model('measured')).
For more information about controller design using SISO D esign Tool
and Co ntrol System Toolbox commands, se e the Control System Toolbox
documentation.
Converting Models to LTI Objects
Control System Toolbox commands o pe rate on LTI objects. To design a
controller for a plant m odel, you must first convert the System Identification
Toolbox model object to an LTI object.
You can convert linear polynomial, state-space, and g rey -box m odel objects,
including
idarx, idpoly, idproc, idss,oridgrey, t o LTI objects.
The following table summarizes the commands for transforming linear
state-space and polynom ial models to an LTI object.
Commands for Converting Models to LTI Objects
Command
Description
Exampl e
frd
Convert to
frequency-response
representation.
ss_sys = frd(model)
ss
Convert to state-space
representation.
ss_sys = ss(model)
tf
Convert to
transfer-function form.
tf_sys = tf(model)
zpk
Convert to zero -pole form.
zpk_sys = zpk(model)
The follow ing code transforms an idmodel object to an LTI state-space object:
% Extract the measured model
% and ignore the noise model
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