Simulink Control Design™ - MathWorks

phase margin is calculated from the angle of G(jωc)C(jωc), where G is the estimated plant,

C is the tuned controller, and ωc is the crossover frequency (bandwidth). The estimated

phase margin might differ from the target phase margin specified by the Target phase

margin (degrees) parameter. It is an indicator of the robustness and stability achieved

by the tuned system.

• Typically, the estimated phase margin is near the target phase margin. In general, the
  larger the value, the more robust is the tuned system, and the less overshoot there is.


• A negative phase margin indicates that the closed-loop system might be unstable.

Dependencies

To enable this port, in the Tuning tab, select Output estimated phase margin achieved

by tuned controller.

frd — Estimated frequency response

vector

This port outputs the frequency-response data estimated by the experiment. Initially, the

value at frd is [0, 0, 0, 0]. During the experiment, the block injects signals at frequencies

[1/3, 1, 3, 10]ωc, where ωc is the target bandwidth. At each sample time during the

experiment, the block updates frd with a vector containing the complex frequency

response at each of these frequencies, respectively. You can use the progress of the

response as an alternative to % conv to examine the convergence of the estimation.

When the experiment stops, the block updates frd with the final estimated frequency

response used for computing the PID gains.

Dependencies

To enable this port, in the Experiment tab, select Plant frequency responses near

bandwidth.

dcgain — Estimated DC gain of plant

scalar

If you select Estimate DC gain with step signal in the Experiment tab, the block

estimates the DC gain of the plant by including a step signal in the injected perturbation.

When the experiment stops, the block updates this port with the estimated DC gain value.

Dependencies

To enable this port, in the Experiment tab, select Plant DC Gain.

16 Blocks — Alphabetical List