I understand that you want to use the sgrid function with root locus to plot grid lines and be able to remove tick labels from the s-plane grid lines. MATLAB doesn’t offer us access to the properties of sgrid tick labels to make these changes but you can try a work-around.
‘sgrid’ offers an option where you can pass ‘zeta’ and ‘wn’ as inputs to it. ‘zeta’ is an array of constant damping factors and ‘wn’ is an array of constant frequencies. This will plot only the grid lines that you specify. Although it will omit some grid lines, you can use this to clean up your plot.
zeta = [0 0.3 0.7 1];
wn = [30 60 100 150 200 260];
sgrid(zeta,wn);
Alternatively, you can also change X and Y limits via Axes Properties to achieve a cleaner plot.
For more information, refer to the sgrid documentation: Generate s-plane grid of constant damping factors and natural frequencies - MATLAB sgrid - MathWorks India
