Simulink Control Design™ - MathWorks

(Tuis.) #1

Analyze Plant Transfer Function


In the watertank model, the Water-Tank System block represents the plant. To obtain
the plant transfer function, add the input and output signals of the Water-Tank System
block as analysis points of sllin.


addPoint(sllin,{'watertank/PID Controller','watertank/Water-Tank System'})
sllin


slLinearizer linearization interface for "watertank":


2 Analysis points:


Point 1:



  • Block: watertank/PID Controller

  • Port: 1
    Point 2:

  • Block: watertank/Water-Tank System

  • Port: 1


No permanent openings. Use the addOpening command to add new permanent openings.
Properties with dot notation get/set access:
Parameters : [1x1 struct], 1 parameters with sampling grid of size 1x3
"Href", varying between 10 and 20.
OperatingPoints : [1x3 opcond.OperatingPoint]
BlockSubstitutions : []
Options : [1x1 linearize.LinearizeOptions]


The first analysis point, which originates at the outport of the PID Controller block, is the
input to the Water-Tank System block. The second analysis point is the output of the
Water-Tank System block.


Obtain the plant transfer function from the input of the Water-Tank System block to the
block output. To eliminate the effects of the feedback loop, specify the block output as a
temporary loop opening.


G = getIOTransfer(sllin,'PID','Tank','Tank');


In the call to getIOTransfer, 'PID', a portion of the block name 'watertank/PID
Controller', specifies the first analysis point as the transfer function input. Similarly,
'Tank', a portion of the block name 'watertank/Water-Tank System', refers to the
second analysis point. This analysis point is specified as the transfer function output
(third input argument) and a temporary loop opening (fourth input argument).


Vary Operating Points and Obtain Multiple Transfer Functions Using slLinearizer Interface
Free download pdf