Simulink Control Design™ - MathWorks

(Tuis.) #1

Nichols Plot


Nichols plot of linear system approximated from nonlinear Simulink model


Library


Simulink Control Design


Description


This block is the same as the Check Nichols Characteristics block except for different
default parameter settings in the Bounds tab.


Compute a linear system from a nonlinear Simulink model and plot the linear system on a
Nichols plot.


During simulation, the software linearizes the portion of the model between specified
linearization inputs and outputs, and plots the open-loop gain and phase of the linear
system.


The Simulink model can be continuous- or discrete-time or multirate and can have time
delays. Because you can specify only one linearization input/output pair in this block, the
linear system is Single-Input Single-Output (SISO).


You can specify multiple open- and closed-loop gain and phase bounds and view them on
the Nichols plot. You can also check that the bounds are satisfied during simulation:



  • If all bounds are satisfied, the block does nothing.

  • If a bound is not satisfied, the block asserts, and a warning message appears at the
    MATLAB prompt. You can also specify that the block:


Nichols Plot
Free download pdf