Simulink Control Design™ - MathWorks

Frequency-Domain Specifications

This example gives a tour of available frequency-domain requirements for control system

tuning with systune or looptune.

Background

The systune and looptune commands tune the parameters of fixed-structure control

systems subject to a variety of time- and frequency-domain requirements. The

TuningGoal package is the repository for such design requirements.

Gain Limit

The TuningGoal.Gain requirement enforces gain limits on SISO or MIMO closed-loop

transfer functions. This requirement is useful to enforce adequate disturbance rejection

and roll off, limit sensitivity and control effort, and prevent saturation. For MIMO transfer

functions, "gain" refers to the largest singular value of the frequency response matrix.

The gain limit can be frequency dependent. For example

s = tf('s');

R1 = TuningGoal.Gain('d','y',s/(s+1)^2);

specifies that the gain from d to y should not exceed the magnitude of the transfer

function.

viewGoal(R1)

Frequency-Domain Specifications