Simulink Control Design™ - MathWorks

Linearization Using Different Rate Conversion Methods

This example shows how to specify the rate conversion method for the linearization of a

multirate model. The choice of rate conversion methodology can affect the resulting

linearized model. This example illustrates the extraction of a discrete linear time invariant

model using two different rate conversion methods.

Example Problem

In the Simulink model scdmrate.mdl there are three different sample rates specified in

five blocks. These blocks are

• sysC - a continuous linear block,


• Integrator - a continuous integrator,


• sysTs1 - a block that has a sample time of 0.01 seconds,


• sysTs2 - a block that has a sample time of 0.025 seconds, and


• Zero-Order Hold - a block that samples the incoming signal at 0.01 seconds.

Open the Simulink model.

scdmrate

In this example, you linearize the model between the output of the block sysTs1 and the

block Zero-Order Hold. Additionally, you add a loop opening at the block Zero-Order

Hold to extract the plant model for the system.

model = 'scdmrate';

io(1) = linio('scdmrate/sysTs1',1,'input');

io(2) = linio('scdmrate/Zero-Order Hold',1,'openoutput');

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