Bode, Nyquist, Root Locus Plots

Bode Plots

The Digital Compensator Design Tool (DCDT) allows you to select the bode plots that are to be displayed (e.g., plant, compensator, etc) as shown in the figure below.

Bode-Plot-Example.PNG

To zoom in on a specific area of the plot, use the left mouse button. Click into the bode plot and drag the mouse, creating a rectangle on the area of interest. To restore the bode plot view, using the left mouse button, click into the bode plot and drag from right-to-left.

Nyquist Plot

The DCDT will compute the nyquist plot for the closed-loop system using the digital compensator selected. This plot can be used to evaluate the overall stability of the system by determining the number of encirclements of the point at (-1,0). Please review the Nyquist stability criterion for more details.

Nyquist-Plot.PNG

Root Locus Plot

The DCDT will compute the root locus plot of the closed-loop system taking into account the digital compensator selected. This plot can be used to determine how the roots of the system or the close loop poles will change with variations to a free system variable (α). We can further clarify this by defining the compensator gain as K(s)=αK’(s) where the α is the term the DCDT will vary and use to perform the calculations for the plots.

Root-Locus-Plot.PNG
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