remove annotations from diskmarginplot

Hey guys! I want to show a system's stability by giving the system's diskmargin by some skew variations. To give a smooth shape of the stable area of the system in complex plane, i stacked all the diskmargin variation by using this script:

% Plant Model
f = pos_motor;
% Plant Diskmargin
s_DOL = -100:1:100;
figure(1)
hold on
for i = 1:numel(s_DOL)
    DOL = diskmargin(f,s_DOL(i));
    diskmarginplot(DOL.GainMargin,'disk')
end
hold off

And this results in a figure:

The description for each diskmargin on the figure is quite a bother. I searched for the solution in function diskmarginoptions but with no success.

Hope anyone can help! Thanks

Answer 1

[Paul]

Hi Muhammad,

Something like this might work, either inside or after the loop. Some experimentation may be needed.

Disk margin plot with annotations.

L = tf(25,[1 10 10 10]);
DM = diskmargin(L);
DGM = DM.GainMargin;
DPM = DM.PhaseMargin;
diskmarginplot(DGM)

Copy the plot to see how it changes

copyobj(gca,figure);

Find the text objects

h = findobj(get(gca,'Children'),'Type','Text')

h = 
  2×1 Text array:

  Text    (DPM = 26 deg)
  Text    (DGM = [0.63,1.6])

Delete them

delete(h)

[Muhammad]

Thanks for your help! I got this working by editing the script to:

% Plant Model
f = pos_motor;
% Plant Diskmargin
s_DOL = -100:1:100;
figure(1)
hold on
for i = 1:numel(s_DOL)
    DOL = diskmargin(f,s_DOL(i));
    diskmarginplot(DOL.GainMargin,'disk')
end
hold off
line_ann = findobj(get(gca,'Children'),'Type','Line');
text_ann = findobj(get(gca,'Children'),'Type','Text');
delete(line_ann(2:end))
delete(text_ann)

Results in: