linmod2
Extract continuoustime linear statespace model around operating point
Syntax
argout
= linmod2('sys
',x
,u
);argout
= linmod2('sys
',x
,u
,para
);
Arguments
 Name of the Simulink^{®} system from which the linear model is extracted. 
 State ( x = Simulink.BlockDiagram.getInitialState('sys'); You
can then change the operating point values within this structure by
editing If the state
contains different data types (for example, 
 A threeelement vector of optional arguments:


linmod and dlinmod both
also return a transfer function and MATLAB^{®} data structure representations
of the linearized system, depending on how you specify the output
(lefthand) side of the equation. Using linmod as
an example:

Description
linmod2
computes a linear statespace model
by perturbing the model inputs and model states, and uses an advanced
algorithm to reduce truncation error.
linmod2
obtains linear models from systems
of ordinary differential equations described as Simulink models.
Inputs and outputs are denoted in Simulink block diagrams using
Inport and Outport blocks.
Notes
By default, the system time is set to zero. For systems that
are dependent on time, you can set the variable para
to
a twoelement vector, where the second element is used to set the
value of t
at which to obtain the linear model.
The ordering of the states from the nonlinear model to the linear model is maintained. For Simulink systems, a character vector variable that contains the block name associated with each state can be obtained using
[sizes,x0,xstring] = sys
where xstring
is a vector of strings whose ith
row is the block name associated with the i
th state.
Inputs and outputs are numbered sequentially on the diagram.
For singleinput multioutput systems, you can convert to transfer
function form using the routine ss2tf
or to zeropole
form using ss2zp
. You can also convert the linearized
models to LTI objects using ss
. This function produces
an LTI object in statespace form that can be further converted to
transfer function or zeropolegain form using tf
or zpk
.
The default algorithms in linmod
and dlinmod
handle
Transport Delay blocks by replacing the linearization of the blocks
with a Pade approximation. For more information, see Linearizing Models.