Simulink Control Design™ - MathWorks

To set up such a model for tuning, create a grid of parameter values. For this example, let

Ks vary from 1 – 5, and let Bs vary from 0.6 – 0.9.

Ks = 1:5;

Bs = [0.6:0.1:0.9];

[Ksgrid,Bsgrid] = ndgrid(Ks,Bs);

These values are the design points at which to sample and tune the system. For example,

create an slTuner interface to the model, assuming one tunable block, a Lookup Table

block named K that models the parameter-dependent gain.

params(1) = struct('Name','Ks','Value',Ksgrid);

params(2) = struct('Name','Bs','Value',Bsgrid);

STO = slTuner('suspension_gs','K',params);

slTuner samples the model at all (Ksgrid,Bsgrid) values specified in params.

Next, use the same design points to create a tunable gain surface for parameterizing K.

design = struct('Ks',Ksgrid,'Bs',Bsgrid);

shapefcn = @(Ks,Bs)[Ks,Bs,Ks*Bs];

K = tunableSurface('K',1,design,shapefcn);

setBlockParam(ST0,'K',K);

After you parameterize all the scheduled gains, you can create your tuning goals and tune

the system with systune.

Eliminate Samples at Unneeded Design Points

Sometimes, your sampling grid includes points that represent irrelevant or unphysical

design points. You can eliminate such design points from the model grid entirely, so that

they do not contribute to any stage of tuning or analysis. To do so, use voidModel, which

replaces specified models in a model array with NaN. voidModel replaces specified

models in a model array with NaN. Using voidModel lets your design over a grid of

design points that is almost regular.

There are other tools for controlling which models contribute to design and analysis. For

instance, you might want to:

• Keep a model in the grid for analysis, but exclude it from tuning.


• Keep a model in the grid for tuning, but exclude it from a particular design goal.

11 Gain-Scheduled Controllers