Simulink Control Design™ - MathWorks

Linear Analysis in a Loop with Fast Restart

In this example, you will trim and linearize a closed loop engine speed control model with

fastRestartForLinearAnalysis.

Open the engine speed control model and get the analysis points for linearization. This is

done to prevent re-compilation between the first call to findop and linearize.

model = 'scdspeedctrl';

open_system(model);

io = getlinio(model);

fopt = findopOptions('DisplayReport','off');

Configure the PI controller to use the base workspace variables kp and ki.

block = [model,'/PID Controller'];

set_param(block,'P','kp');

set_param(block,'I','ki');

Create a grid of parameters to vary.

vp = 0.0005:0.0005:0.003;

vi = 0.0025:0.0005:0.005;

[KP,KI] = ndgrid(vp,vi);

N = numel(KP);

sz = size(KP);

Initialize the base workspace variables kp and ki.

kp = KP(1);

ki = KI(1);

Turn fastRestartForLinearAnalysis on and use io as 'AnalysisPoints'.

fastRestartForLinearAnalysis(model,'on','AnalysisPoints',io);

Perform the linear analysis in a loop. Make sure the block initialization is called after the

parameters are updated when the model is in a compiled state.

ops = operspec(model); % operating point specifications

for i = N:-1:1

kp = KP(i);

ki = KI(i);

Simulink.Block.eval(block); % evaluate the block

op = findop(model,ops,fopt); % trim the model

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