Simulink Control Design™ - MathWorks

If the open-loop response is unstable, make sure to further disable the implicit stability

constraint associated with this requirement.

MaxLG.Stabilize = false;

Figure 1 shows this requirement evaluated for an open-loop response with flexible modes.

Figure 1: Gain constraint on L.

Stability Margins

The TuningGoal.Margins requirement enforces minimum amounts of gain and phase

margins at the specified loop opening site(s). For MIMO feedback loops, this requirement

uses the notion of disk margins, which guarantee stability for concurrent gain and phase

variations of the specified amount in all feedback channels (see diskmargin for details).

For example,the following code enforces dB of gain margin and 45 degrees of phase

margin at a location "u".

13 Control System Tuning Examples