Hey Raymond,
From what I gather, it seems you are not able to turn on closed loop phase information on a Nicholas plot where the closed loop unity feedback grid has been turned on. In MATLAB, when using the ‘nichols’ command to generate a Nichols plot, the default behaviour includes the grid for closed-loop gain (magnitude) contours but does not label the phase contours. To add phase contour information, you can use the ‘ngrid’ function. This allows you to customize the Nichols plot grid.
You can follow these steps to create a plot with closed loop phase information,
- To display the closed-loop phase values on a Nichols plot in MATLAB, start by creating the plot with the ‘nichols’ command for your specific system.
- Following that, invoke the ‘ngrid’ function, which will overlay grid lines corresponding to both magnitude and phase on the plot.
- Then, to identify and manipulate the text labels that represent the phase values, employ the ‘findall’ function to locate all text objects present within the Nichols plot.
- Once you have these text objects, you can alter their properties accordingly to ensure that the closed-loop phase values are visible on the plot.
To learn more about nichols plot please go through the following documentation,
To learn how to plot design using the ‘nichols’ function please go through this documentation,
Hope this helps.
