Simulink Control Design™ - MathWorks

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

[op_point, op_report] = findop(plantMDL,op,options);

x0 = [op_report.States(1).x;op_report.States(2).x];

y0 = op_report.Outputs.y;

u0 = op_report.Inputs.u;

A goal of this example is to obtain plant frequency responses from 0.1 rad/s to 10 rad/s at

two other steady-state operating points, plant output = 0.5 and plant output = -0.5. To

bring the plant to these operating points, design a discrete PID controller at the initial

operating point. Use a controller sample time of 0.01 sec and an open-loop bandwidth is

20 rad/s.

Ts = 0.01;

G0 = c2d(linearize(plantMDL,op_point),Ts);

c = pidtune(G0,'pidf',20);

Online Estimation Using Sinestream Mode

The model scdfreSinestream includes the plant in a PID control loop using the

controller c. It also contains the Frequency Response Estimator block in the control

action + perturbation output configuration. In that configuration, you insert the block

into the control loop between controller and plant.

mdlSS = 'scdfreSinestream';

open_system(mdlSS);

6 Online Frequency Response Estimation