Showing information on a plot

12 views (last 30 days)
Lewis
Lewis on 25 Feb 2024
Commented: Star Strider on 25 Feb 2024
Hello,
I am analysing a control system, that has a step input and the given transfer function. I have been able to produce a graph, and obtain the information of the system (Peak, SettlingMax etc.), but I am trying to display this information as shown below on the MATLAB help centre. Unfortunately, I am unable to locate any guidance on displaying the information in this way (see below for my current graph/desired output)
For reference, my transfer function is g = tf(1,[1,8.52,5.3,26]), and as stated prior a step input is used.
This is my blank graph
An example I found in a textbook
And I am looking to display it in this way.
I
Note - I am able to find the values for each of these via the command stepinfo(g), however would like to show them as the nodes on the image above.
Any help to display my results in a similar way would be greatly appreciated!
Thank you,
Lewis

Accepted Answer

Star Strider
Star Strider on 25 Feb 2024
Retrieving and showing all that information is not straightforward, however it is definitely possible. Use stepinfo to get the information, and stepplot to do the plot since it is easier to work with than step.
This should get you started —
g = tf(1,[1,8.52,5.3,26])
g = 1 --------------------------- s^3 + 8.52 s^2 + 5.3 s + 26 Continuous-time transfer function.
si = stepinfo(g)
si = struct with fields:
RiseTime: 0.6338 TransientTime: 28.8675 SettlingTime: 28.8675 SettlingMin: 0.0149 SettlingMax: 0.0682 Overshoot: 77.2255 Undershoot: 0 Peak: 0.0682 PeakTime: 1.9477
figure
hsp = stepplot(g);
Ampl = hsp.Responses.Data.Amplitude;
Time = hsp.Responses.Data.Time;
xl = xlim;
hold on
plot([1 1]*si.PeakTime, [0 si.Peak], '-.k')
plot([0 si.PeakTime], [1 1]*si.SettlingMax, '-.k')
sttmin = interp1(Ampl, Time, si.SettlingMin); % Interpolate To Determine This Specific Time
plot([-1 1]*max(xl)*0.05+sttmin, [1 1]*si.SettlingMin, '-.k')
plot([0 si.PeakTime], [1 1]*si.SettlingMax, '-.k')
hold off
text(si.PeakTime, si.Peak, sprintf('\\leftarrow Peak = %.4f V\n Time = %.4f s', si.Peak, si.PeakTime), 'Vert','middle')
text(max(xl)*0.05+sttmin, si.SettlingMin, sprintf('\\leftarrow Minimum = %.4f V\n Time = %.4f s', si.SettlingMin, sttmin), 'Vert','middle')
% get(hsp)
Tweak appropriately to get the result you want.
.

More Answers (1)

the cyclist
the cyclist on 25 Feb 2024
You should be able to get everything you want, using the following commands:
title, xlabel and ylabel for the title and axes labels.
line to create the line segments.
annotation to add the text and arrows.
  5 Comments
the cyclist
the cyclist on 25 Feb 2024
Yes, the text command is another option. But annotation can do both arrows and textboxes.
Lewis
Lewis on 25 Feb 2024
Thank you, appreciate it!

Sign in to comment.

Categories

Find more on Discrete Data Plots in Help Center and File Exchange

Products


Release

R2023b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!