Simulink Control Design™ - MathWorks

Block Application

• Varying Lowpass Filter


• Discrete Varying Lowpass

Use these blocks to implement a

Butterworth lowpass filter in which the

cutoff frequency varies with scheduling

variables.

• Varying Notch Filter


• Discrete Varying Notch

Use these blocks to implement a notch filter

in which the notch frequency, width, and

depth vary with scheduling variables.

• Varying PID Controller


• Discrete Varying PID


• Varying 2DOF PID


• Discrete Varying 2DOF PID

These blocks are preconfigured versions of

the PID Controller and PID Controller

(2DOF) blocks. Use them to implement PID

controllers in which the PID gains vary with

scheduling variables.

• Varying Transfer Function


• Discrete Varying Transfer Function

Use these blocks to implement a transfer

function of any order in which the

polynomial coefficients of the numerator

and denominator vary with scheduling

variables.

• Varying State Space


• Discrete Varying State Space

Use these blocks to implement a state-

space controller in which the A, B, C, and D

matrices vary with the scheduling

variables.

• Varying Observer Form


• Discrete Varying Observer Form

Use these blocks to implement a gain-

scheduled observer-form state-space

controller, such as an LQG controller. In

such a controller, the A, B, C, D matrices

and the state-feedback and state-observer

gain matrices vary with the scheduling

variables.

Gain-Scheduled Notch Filter

For example, the subsystem in the following illustration uses a Varying Notch Filter block

to implement a filter whose notch frequency varies as a function of two scheduling

variables. The relationship between the notch frequency and the scheduling variables is

implemented in a MATLAB function.

11 Gain-Scheduled Controllers