Simulink Control Design™ - MathWorks

Modifications for Numeric Stability

When you use a tuning goal with a frequency-dependent specification, the tuning

algorithm uses a frequency-weighting function to compute the normalized value of the

tuning goal. This weighting function is derived from the gain profile that you specify. For

numeric tractability, weighting functions must be stable and proper. For numeric stability,

their dynamics must be in the same frequency range as the control system dynamics. For

these reasons, the software might adjust the specified gain profile to eliminate

undesirable low-frequency or high-frequency dynamics or asymptotes. The process of

modifying the tuning goal for better numeric conditioning is called regularization.

For example, consider the following tracking goal.

R1 = TuningGoal.Tracking('r','y',tf([1 0 0],[1 2 1]));

viewGoal(R1)

10 Control System Tuning